Additional photography by Lawrence L. C. Jones, René C. Clark, Gary Nafis, and others

Transcription

1 For both the casual observer and the experienced naturalist, this indispensable ield guide and natural history reference covers all the salamanders, frogs, spadefoots, toads, lizards, snakes, tortoises, and turtles in Arizona. Over 200 stunning photographs, accompanied by range maps, show key details of identi ication. Fascinating life history and behavior accounts will leave the reader amazed at the biodiversity of Arizona, where the convergence of the ponderosa forests and subalpine meadows of the Colorado Plateau with the Chihuahuan, Sonoran, and Mojave deserts has resulted in a unique herpetofauna. Days are dominated by an astonishing variety of lizards; at night, by Gila monsters, geckos, and snakes. And when the summer monsoon sets in, the desert night comes alive with millions of toads and spadefoots. Additional photography by Lawrence L. C. Jones, René C. Clark, Gary Nafis, and others

2 Arizona s Amphibians & Reptiles, A Natural History and Field Guide, by Murphy with Jones and Clark, is an up to date and beautifully illustrated book that focuses on the herpetofauna that is the envy of professional and amateur herpetologists throughout the world. By day, lizards dominate the landscape, with occasional coachwhips sliding through in search of prey. The bizarre horned lizards stationed along ant trails, collared lizards poised on rocks as though they are sentinels of something we don t understand, and the many species of whiptail lizards, some of which reproduce parthenogenetically (cloning). At night, an entirely different and equally strange herpetofauna appears, with Gila monsters bumbling along, banded geckos, and a host of snake species from tiny threadsnakes to the numerous rattlesnake species. When summer monsoon rains hit, the nighttime desert comes alive with millions of toads, including the mysterious spadefoots, which form cocoons around their bodies by shedding multiple times after burrowing deep into the desert soil where they can hang out inactive for a year or more. Massive Sonoran Desert toads produce skin secretions causing a psychedelic effect when licked and tiny Mazatlán narrowmouthed toads hang out underneath tarantulas in their burrows when it is dry. Each species has a story to tell, and the more we learn, the more we discover that we are just scratching the surface as we seek to understand how so many species can live in one state, much of which is covered by desert. This book summarizes what is known about each species, with lots of interesting anecdotes that should whet any naturalist s imagination. This is a must-have for anyone interested in Arizona s spectacular fauna, and for those of you who are bird watchers, watch your step! Laurie J. Vitt George Lynn Cross Research Professor University of Oklahoma (Tubac, Arizona resident)

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4 Arizona s Amphibians & Reptiles A Natural History and Field Guide John C. Murphy Additional photography by Lawrence L. C. Jones, René C. Clark, Gary Nafis, and others

5 Arizona s Amphibians & Reptiles Copyright 2018 by John C. Murphy All rights reserved. No part of this book may be reproduced in any form or by any electronic or mechanical means including information storage and retrieval systems, without permission in writing from the publisher. Printed in the United States of America First Printing March 2018 ISBN Paperback ISBN Hardcover Published by: Book Services ii

6 This book is dedicated to the survival of Arizona s Amphibians & Reptiles. iii

7 Arizona s Amphibians & Reptiles Front Cover: Sidewinder (JCM). Back Cover: Sonoran Desert Tortoise (JCM), Eastern Collard Lizard (JCM), Chihuahuan Green Toad (JCM), Organ Pipe Shovel-nosed Snake (LLCJ), and a Gila Monster (JCM). Inside Front Cover: Black-Necked Gartersnake (RCC) Inside Back Cover: Gila Spotted Whiptail (JCM). Inside Dedication page: Western Diamondback Rattlesnake (JCM). iv

8 Acknowledgments Many people contributed to this book in a variety of ways. For assistance in the field, assistance obtaining permits, and for providing access to animals for photography I would like to thank: Tom Anton Jim Atkinson Phil Collura Terry Cox Mark Hammond at Animal Experts Roger Nelson at Green Valley Canine Roger Repp, Larry Rowan, and Peter Holm at Organ Pipe Cactus National Monument. For the photographs, I sincerely thank: Tom G. Anton (TGA) Randy Babb... (RB) René C. Clark... (RCC) Terry J. Hibbits... (TJH) John Iverson... (JI) John C. Murphy... (JCM) Daren Riedle... (DR) Laurie J. Vitt... (LJV) Jim Atkinson...(JA) Tom C. Brennan...(TCB) Terry E. Hibbits...(TEH) Troy Hibbits...(TH) Lawrence L. C. Jones. (LLCJ) Gary Nafis...(GN) Jim Rorabaugh...(JR) Brad Wilson...(BW) Photos are marked with the photographer s initials in the lower corner. For comments on the content, writing, and photography my sincerest thanks go to Jim Rorabaugh, who provided an extensive and highly useful critique, as well as to: Betsy Feinberg Shea Lambert Hanna Strauss Rudolph Thut Maggie Fusari Walter Sobzak Robert Villa Drawing used in the appendices are from a variety of sources and have been re-drawn with Adobe Illustrator. Edward D. Cope s 1900 monograph on Crocodiles, Lizards, and Snakes of North American. Hobart M. Smiths 1957 Handbook of Lizards. Cochran and Goin s 1970 The New Field Book of Reptiles and Amphibians. v

9 Arizona s Amphibians & Reptiles Arizona Counties vi

10 Preface Interest in Arizona s herpetofauna was first stimulated by the US Army s Pacific Railroad Surveys ( ) that explored possible routes for a transcontinental railroad. The expedition s biologists were given instructions on how to collect and handle specimens, and they were outfitted by Spencer Fullerton Baird, Assistant Secretary of the Smithsonian. Baird and Charles Girard followed up on the specimens returned by the expeditions, and they described about 30 of the 188 species and subspecies recognized in this book. Biological knowledge has exploded since the days of Baird and Girard. Species concepts have multiplied and mutated into dozens of slightly differing ideas. Sorting 35 mm slides from trips to Arizona in the 1970s- 90s, I realized not only had the photographic technology undergone radical evolution, but many of the scientific names had also changed. Along with the ability to sequence genes and compare them has come the realization that biodiversity is substantially greater than previously thought. Species are constantly being split, and only occasionally lumped, in the 21 st century. This is in part the result of the polytypic species concept that lumped populations that were quite different into a single species. Molecular techniques, combined with second looks at morphology, are redefining old species and describing new ones. This volume attempts to provide the reader with an overview of the Arizona herpetofauna, provide the information necessary to identify the state s amphibians and reptiles, and to summarize some of what is known about their natural history. This is not as straightforward as one might expect. Variation within a species can be bewildering. Males and females are often distinctly different, and juveniles can have coloration and patterns that make them look unlike their parents. Populations are often selected for the coloration of the background they live on, so two populations may be close geographically but be living on rock and soil of different colors. The known biodiversity of the state will increase as more studies are done. The reader should expect changes to the fauna as new information becomes available. My biggest regret in publishing this book is that it is not triple the size. There is a substantial amount of research that has gone into the Arizona herpetofauna. This volume is but an incomplete snapshot of that information. vii

11 Arizona s Amphibians & Reptiles Contents Acknowledgments...v Arizona Counties.... vi Preface...vii Arizona and its Herpetofauna....1 Geological Events, Barriers, and Speciation...3 Diversity, Extinction, and Conservation...6 This Book and Others...9 A Note on Frog Calls...11 Amphibia...14 Spadefoots...15 Couch s Spadefoot, Scaphiopus couchii Baird, Plains Spadefoot, Spea bombifrons Cope, Great Basin Spadefoot, Spea intermontana Cope, Mexican Spadefoot, Spea multiplicata Cope, Toads...24 Great Plains Toad, Anaxyrus cognatus (Say, 1822)...24 Chihuahuan Green Toad, Anaxyrus debilis (Girard, 1854)...25 Arizona Toad, Anaxyrus microscaphus (Cope, 1867)...28 Red-Spotted Toad, Anaxyrus punctatus (Baird & Girard, 1852)...29 Sonoran Green Toad, Anaxyrus retiformis (Sanders and Smith, 1951)...31 Woodhouse s Toad, Anaxyrus woodhousii (Girard, 1854)...32 Sonoran Desert Toad, Incilius alvarius (Girard, 1859)...33 Treefrogs...36 Blanchard s Cricket Frog, Acris blanchardi (Harper, 1947)...36 Canyon Treefrog, Dryophytes arenicolor (Cope, 1866)...37 Arizona Treefrog, Dryophytes wrightorum (Taylor, 1938)...39 Baja California Treefrog, Hyliola hypochondriaca (Hallowell, 1854)...40 Boreal Chorus Frog, Pseudacris cf. maculata...42 Lowland Burrowing Treefrog, Smilisca fodiens (Boulenger, 1882)...43 True Frogs...45 Rio Grande Leopard Frog, Lithobates berlandieri (Baird, 1859) [Introduced]...46 Plains Leopard Frog, Lithobates blairi (Mecham, Littlejohn, Oldham, Brown & Brown, 1973) 46 American Bullfrog, Lithobates catesbeianus (Shaw, 1802) [Introduced] Chiricahua Leopard Frog, Lithobates chiricahuensis (Platz & Mecham, 1979)...48 Relict Leopard Frog, Lithobates onca (Cope, 1874)...51 Northern Leopard Frog, Lithobates pipiens (Schreber 1782)...52 Tarahumara Frog, Lithobates tarahumarae (Boulenger, 1917)...53 Lowland Leopard Frog, Lithobates yavapaiensis (Platz & Frost, 1984)...55 The Barking Frog...57 Barking Frog, Craugastor augusti (Dugès, 1879)...57 The Narrow-Mouthed Toad...60 Sinaloan Narrow-Mouthed Toad, Gastrophryne mazatlanensis (Taylor, 1943)...60 viii

12 Contents Pipidae...62 African Clawed Frog, Xenopus laevis (Daudin, 1802) [Introduced]...62 Salamanders in Arizona...64 Mole Salamanders...65 Western Tiger Salamander, Ambystoma mavortium (Baird, 1850)...68 Reptilia...71 Turtles and Tortoises The Snapping Turtle...74 Common Snapping Turtle, Chelydra serpentina (Linnaeus, 1758) [Introduced]...74 Emydid Turtles...75 Painted Turtle, Chrysemys picta (Schneider, 1783)...75 Ornate Box Turtle, Terrapene ornata (Agassiz, 1857)...76 Pond Slider, Trachemys scripta (Thunberg, 1792) [Introduced]...79 Mud Turtles...79 Yellow Mud Turtle, Kinosternon flavescens (Agassiz, 1857)...80 Sonoran Mud Turtle, Kinosternon sonoriense (LeConte, 1854)...81 Arizona Mud Turtle, Kinosternon stejnegeri (Hartweg, 1938)...83 Tortoises...84 Mojave Desert Tortoise, Gopherus agassizii (Copper, 1863)...86 Sonoran Desert Tortoise, Gopherus morafkai (Murphy, Berry, Edwards, Leviton, Lathrop & Riedle 2011)...88 The Softshell Turtle...89 Spiny Softshell, Apalone spinifera (LeSueur, 1827) [Introduced]...90 Squamata...91 Iguanas...92 Spiny-tailed Iguanas, Ctenosaura macrolopha (Smith, 1972) and Ctenosaura conspicuosa (Dickerson, 1919) [Introduced] Desert Iguana, Dipsosaurus dorsalis (Baird & Girard, 1852)...93 Common Chuckwalla, Sauromalus ater (Duméril, 1856)...96 Collared and Leopard Lizards...99 Great Basin Collared Lizard, Crotaphytus bicinctores (Smith & Tanner, 1972) Eastern Collared Lizard, Crotaphytus collaris (Say, 1823) Sonoran Collared Lizard, Crotaphytus nebrius (Axtell & Montanucci, 1977) Long-Nosed Leopard Lizard, Gambelia wislizenii (Baird & Girard, 1852) Phrynosomatids Sand Lizards Zebra-Tailed Lizard, Callisaurus draconoides (Blainville, 1835) Greater Earless Lizard, Cophosaurus texanus (Troschel, 1852) Elegant Earless Lizard, Holbrookia elegans (Bocourt, 1874) Common Lesser Earless Lizard, Holbrookia maculata (Girard, 1851) Yuman Desert Fringe-Toed Lizard, Uma rufopunctata (Cope, 1895) Mojave Fringe-Toed Lizard, Uma scoparia (Cope, 1894) Mohawk Dunes Fringe-Toed Lizard, Uma sp Horned Lizards Texas Horned Lizard, Phrynosoma cornutum (Harlan, 1825) Goode s Horned Lizard, Phrynosoma goodei (Stejneger, 1893) Greater Short-Horned Lizard, Phrynosoma hernandesi (Girard, 1858) Flat-Tailed Horned Lizard, Phrynosoma mcallii (Hallowell, 1852) ix

13 Arizona s Amphibians & Reptiles Round-Tailed Horned Lizard, Phrynosoma modestum (Girard, 1852) Desert Horned Lizard, Phrynosoma platyrhinos (Girard, 1852) Regal Horned Lizard, Phrynosoma solare (Gray, 1845) Spiny Lizards & Fence Lizards Twin-Spotted Spiny Lizard, Sceloporus bimaculosus (Phelan & Brattstrom 1955) Clark s Spiny Lizard, Sceloporus clarkii (Baird & Girard, 1852) Southwestern Fence Lizard, Sceloporus cowlesi (Lowe & Norris, 1956) Common Sagebrush Lizard, Sceloporus graciosus (Baird & Girard 1852) Yarrow s Spiny Lizard, Sceloporus jarrovii (Cope, 1875) Desert Spiny Lizard, Sceloporus magister (Hallowell, 1854) Slevin s Bunchgrass Lizard, Sceloporus slevini (Smith, 1937) Plateau Lizard, Sceloporus tristichus (Cope & Yarrow, 1875) Yellow-Backed Spiny Lizard, Sceloporus uniformis (Phelan & Brattstrom, 1955) Striped Plateau Lizard, Sceloporus virgatus (Smith, 1938) Brush & Tree Lizards Long-Tailed Brush Lizard, Urosaurus graciosus (Hallowell, 1854) Ornate Tree Lizard, Urosaurus ornatus (Baird & Girard, 1852) The Side-Blotched Lizards Common Side-Blotched Lizard, Uta stansburiana (Baird & Girard, 1852) Eastern Side-blotched Lizard, Uta stejnegeri (Schmidt 1921) Whiptails Chihuahuan Spotted Whiptail, Aspidoscelis exsanguis (Lowe, 1956) Gila Spotted Whiptail, Aspidoscelis flagellicauda (Lowe & Wright, 1964) Little Striped Whiptail, Aspidoscelis inornata (Baird, 1859) New Mexico Whiptail, Aspidoscelis neomexicana (Lowe and Zweifel, 1952) [Introduced]. 154 Pai Striped Whiptail, Aspidoscelis pai (Wright and Lowe, 1933) Priscilla s Whiptail Lizard, Aspidoscelis priscillae (Cole et al. 2017) Sonoran Spotted Whiptail, Aspidoscelis sonorae (Lowe & Wright, 1964) Giant Spotted Whiptail, Aspidoscelis stictogramma (Burger, 1950) Tiger Whiptail, Aspidoscelis tigris (Baird & Girard, 1853) Desert Grassland Whiptail, Aspidoscelis uniparens (Wright & Lowe, 1965) Plateau Striped Whiptail, Aspidoscelis velox (Springer, 1928) Red-Backed Whiptail, Aspidoscelis xanthonota (Duellman & Lowe, 1953) The Alligator Lizard Madrean Alligator Lizard, Elgaria kingii (Gray, 1838) Skinks Ocellated Skink, Chalcides cf. ocellatus [Introduced] Mountain Skink, Plestiodon callicephalus (Bocourt, 1879) Many-Lined Skink, Plestiodon multivirgatus (Hallowell, 1857) Great Plains Skink, Plestiodon obsoletus (Baird & Girard, 1852) Western Basin Skink, Plestiodon skiltonianus (Baird and Girard, 1852) Gilbert s Skink, Plestiodon gilberti (Van Denburgh, 1896) Geckos Eublepharidae Western Banded Gecko, Coleonyx variegatus (Baird, 1859) Gekkonidae Mediterranean Gecko, Hemidactylus turcicus (Linnaeus, 1758) [Introduced] Night Lizards Arizona Night Lizard, Xantusia arizonae (Klauber, 1931) x

14 Contents Bezy s Night Lizard, Xantusia bezyi (Papenfuss, Macey, & Schulte, 2001) Yucca Night Lizard, Xantusia vigilis (Baird, 1859) The Gila Monster Gila Monster, Heloderma suspectum (Cope, 1869) Ancient Living Snakes New Mexico Threadsnake, Rena dissecta (Cope, 1860) The Western Threadsnake, Rena humilis (Baird & Girard, 1853) Trans-Pecos Threadsnake, Rena segrega (Klauber, 1939) The Blindsnake Brahminy Blindsnake, Indotyphlops braminus (Daudin, 1803) [Introduced] The Rosy Boas Northern Three-Lined Boa, Lichanura orcutti (Stejneger, 1889) Rosy Boa, Lichanura trivirgata (Cope, 1861) Colubrine Snakes The Neotropical Treesnake Clade Thornscrub Vine Snake, Oxybelis cf. aeneus Miniature Snakes that Eat Arthropods Variable Sand Snake, Chilomeniscus stramineus (Cope, 1861) Desert Shovel-Nosed Snake, Chionactis annulata (Baird, 1859) Mojave Shovel-Nose Snake, Chionactis occipitalis (Stickel, 1941) Organ Pipe Shovel-Nosed Snake, Chionactis palarostris (Klauber, 1937) Western Ground Snake, Sonora semiannulata (Girard 1853) Chihuahuan Hook-Nosed Snake, Gyalopion canum (Cope 1861) Thornscrub Hook-Nosed Snake, Gyalopion quadrangulare (Günther, 1893) Smith s Black-Headed Snake, Tantilla hobartsmithi (Taylor, 1937) Plains Black-Headed Snake, Tantilla nigriceps (Kennicott, 1860) Chihuahuan Black-Headed Snake, Tantilla wilcoxi (Stejneger, 1902) Yaqui Black-Headed Snake, Tantilla yaquia (Smith, 1942) Racers & Relatives Sonoran Whipsnake, Coluber bilineatus (Jan, 1863) Western Yellow-Bellied Racer, Coluber constrictor (Linnaeus, 1758) Striped Whipsnake, Coluber taeniatus (Hallowell, 1852) Coachwhip, Masticophis flagellum (Shaw, 1802) Patch-Nosed Snakes and the Lyresnake Big Bend Patch-Nosed Snake, Salvadora deserticola (Schmidt, 1940) Eastern Patch-Nosed Snake, Salvadora grahamiae (Baird & Girard, 1853) Western Patch-Nosed Snake, Salvadora hexalepis (Cope, 1866) Sonoran Lyresnake, Trimorphodon lambda (Cope, 1886) Leaf-Nosed Snakes Saddled Leaf-Nosed Snake, Phyllorhynchus browni (Stejneger, 1890) Spotted Leaf-Nosed Snake, Phyllorhynchus decurtatus (Cope, 1869) Kingsnakes, and their Relatives Green Rat Snake, Senticolis triaspis (Cope, 1866) Long-Nosed Snake, Rhinocheilus lecontei (Baird & Girard, 1853) Glossy Snake, Arizona elegans (Baird, 1859) Gophersnake, Pituophis catenifer (Blainville, 1835) Kingsnakes and Milk Snakes California Kingsnake, Lampropeltis californiae (Blainville, 1835) Western Black Kingsnake, Lampropeltis nigrita (Zweifel & Norris, 1955) xi

15 Arizona s Amphibians & Reptiles The Western Milksnake, Lampropeltis gentilis (Baird & Girard 1853) Desert Kingsnake, Lampropeltis splendida Baird & Girard, Knobloch s Mountain Kingsnake, Lampropeltis knoblochi (Taylor 1940) Arizona Mountain Kingsnake, Lampropeltis pyromelana (Cope, 1867) Dipsadid Snakes Ring-Necked Snake, Diadophis punctatus (Linnaeus, 1766) Mexican Hog-Nosed Snake, Heterodon kennerlyi (Kennicott, 1860) Desert Nightsnake, Hypsiglena chlorophaea (Cope, 1860) Chihuahuan Nightsnake, Hypsiglena jani (Stejneger, 1893) Gartersnakes & Water Snakes Banded Watersnake, Nerodia fasciata (Linnaeus, 1766) [Introduced] Black-Necked Gartersnake, Thamnophis cyrtopsis (Kennicott 1860) Terrestrial Gartersnake, Thamnophis elegans (Baird & Girard, 1853) Mexican Gartersnake, Thamnophis eques (Reuss, 1834) Checkered Gartersnake, Thamnophis marcianus (Baird & Girard, 1853) Narrow-Headed Gartersnake, Thamnophis rufipunctatus (Cope, 1875) Coral Snakes Sonoran Coral Snake, Micruroides euryxanthus (Kennicott, 1861) Rattlesnakes Grand Canyon Rattlesnake, Crotalus abyssus (Klauber, 1930) Arizona Black Rattlesnake, Crotalus cerberus, (Coues, 1875) Midget Faded Rattlesnake, Crotalus concolor (Woodbury, 1929) Great Basin Rattlesnake, Crotalus lutosus (Klauber, 1930) Prairie Rattlesnake, Crotalus viridis (Rafinesque, 1818) Western Diamondback Rattlesnake, Crotalus atrox, (Baird and Girard, 1853) Sidewinder, Crotalus cerastes (Hallowell, 1854) Rock Rattlesnake, Crotalus lepidus (Kennicott, 1861) Western Black-Tailed Rattlesnake, Crotalus molossus (Baird & Girard, 1953) Twin-spotted Rattlesnake, Crotalus pricei (Van Denburgh, 1895) Southwestern Speckled Rattlesnake, Crotalus pyrrhus (Cope, 1861) Mojave Rattlesnake, Crotalus scutulatus (Kennicott, 1861) Tiger Rattlesnake, Crotalus tigris (Kennicott, 1859) Arizona Ridge-Nosed Rattlesnake, Crotalus willardi (Meek, 1906) New Mexico Ridge-Nosed Rattlesnake, Crotalus obscurus (Harris & Simmons, 1974) Western Massasauga, Sistrurus tergeminus (Say, 1823) Appendix References Index Author & Photographer Information xii

16 Arizona and its Herpetofauna Arizona is 295,000 square kilometers of biological diversity, the result of the confluence of the Colorado Plateau with the Mojave, Sonoran, and Chihuahuan deserts. The differences in topography produce many localized climates and microhabitats. Lower elevations tend to be desert, with mild winters and hot summers. Upper elevations tend to be cooler and wetter, with cold winters and mild summers. Diurnal temperature variations in the deserts and mountains can differ dramatically. Urban areas have become heat islands, being warmer than the natural environments found around them. Arizona s average annual rainfall is 32 cm, which falls during two rainy seasons. Pacific cold fronts produce winter (actually, late fall through early spring) rains, with prevailing winds coming from the west. Winter rains are cool, and rainfall is usually widespread, steady, and light. During late spring and summer, the wind pattern shifts, coming from the south, initiating the North American monsoon. Rains come from moisture-laden air from the Gulf of California and the Gulf of Mexico. Summer storms are spotty, but may be intense, bringing lightning, thunder, wind, and torrential downpours that move over much of the eastern two-thirds of the state. The western part of the state is much drier and receives fewer monsoonal storms. Historically, the monsoon starts about 4 July and ends sometime in September. However, it may start as early as mid-june and extend into fall. On occasion, tropical cyclones in the eastern Pacific (e.g., Baja California) may pump large quantities of moisture into the Arizona atmosphere during the fall, thereby extending the functional monsoon into October or even early November. The additional precipitation is sometimes separated from the monsoons and termed the chubasco. In the past, the North American monsoon was defined by subsequent days of high dewpoint, but in recent years, the National Weather Service has defined the start as 15 June and the end as 30 September. While these specific dates are useful for annual recordkeeping, the reptiles and amphibians respond to the actual dewpoint. Amphibians tend to stay small, providing a high surface-to-volume ratio useful for absorbing water and exchanging gases across their skin. The largest Arizona amphibian is the Sonoran Desert Toad, Incilius alvarius, which reaches 191 mm in body length. The smallest Arizona frogs are the Sinaloan Narrow-mouthed Toad and the Boreal Chorus Frog, which barely reach 40 mm in body length. Adult amphibians are carnivores, with most species feeding on invertebrates. However, the larval stages often graze on algae, or filter water and mud for organic material. A few however, are cannibals. 1

17 Arizona s Amphibians & Reptiles Perhaps what makes amphibians so interesting are the varieties of adaptation they display within their life histories. They have managed to adapt to a vast range of ecological niches with their diverse anatomies, physiologies, and reproductive strategies. Amphibian reproduction is usually dependent on a source of free water. As one might expect, amphibians are relatively few in dry landscapes, although a surprising number of species have adapted to life in Arizona s arid lands. Most of the desert and thornscrub species are explosive breeders, timing their reproduction with the monsoon. At times, there can be a cacophony of calls from several species using storm water ponds, especially after the first heavy rains of summer. Reptiles inhabit all continents and seas except Antarctica. Most diversity occurs on either side of the equator and decreases at higher latitudes. Reptiles differ from amphibians in many ways. Most significantly, they have reduced their dependency on water for reproduction with the evolution of the land egg, a self-contained environmental chamber for the reptilian embryo. The Gila Monster and the Common Chuckwalla are the largest lizards native to the state, while the Gophersnake, Coachwhip, and Western Diamondback Rattlesnake are the largest snake species within Arizona. On the other end of the size spectrum, there are the tiny night lizards and worm-like threadsnakes. The Squamata (lizards and snakes) is species-rich, with more than 10,000 species worldwide. Along with other states that border Mexico, Arizona has the highest diversity of squamates in the United States. Testudines the turtles, terrapins, and tortoises comprise about 350 species, but are poorly represented in Arizona. Like the amphibians, most reptiles are ectothermic; that is, they usually don t use energy from food to heat their bodies as do mammals and birds, which are endothermic. Instead, reptiles absorb thermal energy for body heat, sometimes directly from sunshine. Reptiles often shuttle from cool to warm environments and collect heat until their muscles are warm enough to search for food and mates. Many amphibians and some reptiles are thermal conformers and have a body temperature that is not much different from the ambient temperature. Scales and scutes covering reptile skin reduce water loss and provide protection from environmental hazards. Reptiles lack the aquatic larval stage found in amphibians. While most reptiles are oviparous (egg-laying), about 20% have live birth. Many of the viviparous species inhabit high altitudes, feed their embryos through placenta-like structures similar to mammals, and maintain the embryonic temperature by moving in and out of sunlight. Some species even provide parental care after hatching or birth. Lizards and snakes have skin covered in epidermal scales that usually overlap. Turtles and crocodile scales are of dermal origin, rather than epidermal origin, and are termed scutes. Turtle shells are composed of fused scutes, and their rib cage and vertebral column are usually fused to the shell s carapace. 2

18 Arizona and its Herpetofauna Reptiles are mostly carnivorous and have relatively short digestive tracts, protein and fats being simple to digest. There are exceptions. The iguanas and the tortoises are mostly herbivorous and have a complex digestive system that includes a hindgut fermentation chamber that allows the animal to extract more calories from its food. Geological Events, Barriers, and Speciation The combination of fossils and the molecular clock (Kumar, 2005) have allowed dates of divergence to be calibrated for many amphibians and reptile taxa. These divergence dates often align with geological events. In Arizona, numerous geological events have acted to produce the current landscape and the species that inhabit those landscapes. The events influencing the Arizona landscape were not always within the current state boundaries, but in surrounding areas. These events have influenced the distribution of the current herpetofauna. Gámez et al. (2016) discussed some events between 23 and 0.11 MYA (millions of years ago) that influenced the current flora and fauna of the southwestern United States and northern Mexico. I have used an abbreviated list from this source. Formation of the Colorado River between the Great Basin and the Colorado Plateau develops and drains to the southeast into the Madrean Archipelago (about 10 MYA). The Mojave and Sonoran Desert Spiny Lizards diverged from each other about MYA (Wood et al. 2012). Extensional tectonism of the Colorado Plateau (6-5 MYA) was a major factor in the excavation of the Grand Canyon and in the establishment of the present drainage pattern of the Colorado River to the Gulf of California. At various times the river has been a barrier and at other times it has not. The California Gulf opens (5-3 MYA); parts of Arizona, Sonora, and Sinaloa are inundated with saltwater, and the Baja California Peninsula moves to the northwest. The Mojave and Sonoran Sidewinder populations diverged from each other about 3.28 MYA ( MYA). The Mojave and Sonoran Yucca Night Lizard populations diverged about MYA. Mojave and Sonoran Rosy Boas diverged from each other about MYA (Wood et al. 2012). The western and eastern Western Diamondback Rattlesnake populations were also likely separated by this event (Myers et al, 2016). A minimum of eleven glacial advances of the polar ice sheet lowered the temperature 5-6 C throughout North America. The result was flora and fauna migrations as the temperatures cycled. The Red-spotted Toad populations in the Mojave and Sonoran Deserts diverged from each other about MYA (Wood et al. 2012). There are a variety of barriers that prevent individuals of a species from getting together to reproduce or prevent a species from expanding its distribution. These barriers isolate populations and contribute to producing new genetic lineages and 3

19 4 Arizona s Amphibians & Reptiles new species. The barriers may be invisible, such as temperature or moisture gradients. Or they may be visible structures or communities, such as rivers, mountains, forests, deserts, or grasslands. Below is a short discussion of some of the barriers in Arizona that have been examined by various researchers over the years. The Cochise Filter Barrier. The climatic shifts in the Pleistocene-Holocene have periodically separated and reconnected the Sonoran and Chihuahuan deserts. The beginning of the Pleistocene (~1.8 MYA) resulted in a sharp transition from tropical conditions to a cool, more continental climate. During glacial periods, cooler, wetter conditions allowed woodlands to expand into areas formerly occupied by desert, restricting arid regions to lowland basins below 300 m ASL (Above Sea Level). The continuing climatic changes resulted in a shift from Late Wisconsin pinyon-juniperoak woodland to early Holocene oak-juniper woodland to middle Holocene desert grassland, and finally, late Holocene Chihuahuan desertscrub. Warmer interglacial periods, such as the present one marking the beginning of the Holocene, 11,000 YBP (Years Before Present), produced expanding deserts. The Sonoran and Chihuahuan deserts established their current distributions about 9,000 YBP during the maximum warmth following the Last Glacial Maximum. The Madrean Line. University of Arizona herpetologist, Charles H. Lowe (1992), proposed a barrier in the distribution of the herpetofauna of southern Arizona and New Mexico between the Madrean Archipelago and the Rocky Mountains along a line that roughly parallels present-day Interstate 10. Swann et al. (2005) categorized species by elevation and geographic region and used spatial analysis to investigate the existence and location of the Madrean Line. They found a difference in species north and south of Interstate 10 and located a clear boundary where Lowe s predicted Madrean line occurs. Nine of twelve species they examined were not found north of the line and have Madrean distributions, and seven of the nine species do not occur north of I-10. They found only one montane species, the Arizona Black Rattlesnake, with a northern distribution and note that two species (the Sonoran Mountain Kingsnake and the Short-horned Lizard) occur in all of the sky Islands and range well to the north and south. Since the publication of their paper, the Sonoran Mountain Kingsnake has been divided into northern (Arizona Mountain Kingsnake) and southern (Knobloch s Mountain Kingsnake) species. The Short-horned Lizard as currently understood has a range extending from southern Canada to Mexico and is in need of further study. The Striped Whipsnake and Mexican Gartersnake were added to the northern group and the Twin-spotted Rattlesnake was noted as the only species in the Pinaleño Mountains that is otherwise exclusively from southern ranges (Bezy and Cole, 2014). They consider this a biogeographic anomaly that remains to be solved and suggest that the herpetofauna of the Madrean Archipelago can be considered a segment in the transition between the Neotropics and the North Temperate Zone. Species ranging north from thornscrub, tropical deciduous forest, and the Pacific

20 Arizona and its Herpetofauna slopes of the Sierra Madre Occidental become increasingly restricted to the mountain ranges of the archipelago, as Sonoran and Chihuahuan desertscrub come to dominate the valleys and bajadas (alluvial fans at the base of mountains). To the north, the increased precipitation and cooler summer temperatures at higher elevations become hostile environments to amphibians and reptiles due to freezing winter temperatures. Today s northern limit of the summer-monsoon-adapted Madrean evergreen woodland is just below the Mogollon Rim. And the winter-precipitationadapted interior chaparral extends southward to the Sierrita Mountains. Bezy and Cole suggest that the two biotic communities overlap by about 263 km in Arizona, where the montane herpetofauna transitions from the Sierra Madre Occidental to the Colorado Plateau. The Mogollon Rim. The Rim is an escarpment defining the southwestern edge of the Colorado Plateau. The escarpment was created by erosion and faulting, cutting dramatic canyons into it, including Fossil Creek Canyon and Pine Canyon. Much of the topography south of the Mogollon Rim is 1,200-1,500 m above sea level, while the escarpment rises to about 2,400 m. The Rim s slopes and the plateau have extensive ponderosa pine forests. The Mogollon Rim is a major barrier, with Rocky Mountain flora and fauna on the top of the plateau, and species native to the Mexican Sierra Madre Occidental on the slopes below and in the Madrean sky islands to the south. The Mogollon Rim separates low desert from upland forest and forms a barrier for numerous organisms, ranging from cottonwood trees to mammals, and including Mountain Kingsnakes and Barking Frogs. Burbrink et al. (2011) found little or no gene flow between lineages of Mountain Kingsnake above and below the Mogollon Rim and suggest that isolation at high elevation resulted in the two species of Mountain Kingsnakes. And the Rim appears to be the northern barrier for the Barking Frog (Goldberg et al. 2004). The Colorado River. Species inhabiting the Mojave and Sonoran Deserts also show differentiation. Wood et al. (2012) found that species shared between these two deserts can be categorized into three groups: (1) those with lineage breaks across the Colorado River; (2) those with breaks along the Mojave and Sonoran Desert ecotone; and (3) those with breaks at both. All three categories showed that lineage breaks were relatively ancient, occurring in the late Pliocene or older. However, they did find three species that diverged in the Pleistocene. In some cases, Wood et al. (2014) found lineages that extended slightly on both sides of the Colorado River (Rosy Boa and the Flat-Tailed Horned Lizard), usually along the southern portion of the river. This pattern was also observed in the desert tortoise and fringe-toed lizards. In these cases, the species were able to disperse across the river but did not disperse far from the river. 5

21 Arizona s Amphibians & Reptiles Diversity, Extinction, and Conservation Concern about widespread amphibian declines came to the attention of the herpetological community in Follow-up studies revealed the severity of the declines. At a study site in Costa Rica, 40% of the amphibian fauna disappeared over a short period in the late 1980s. The sudden disappearance of several species of neotropical frogs from pristine habitats suggested amphibians were in trouble. Skeptics considered these normal fluctuations in amphibian populations. Further investigations revealed this was not the case, as the declines were far more widespread and severe than would occur under normal conditions. Most herpetologists became convinced that amphibian declines were not random. Stuart et al. (2004) noted 427 species (7.4%) were Critically Endangered, the highest threat category of the IUCN (International Union for Conservation of Nature), as compared with 1.8% of birds and 3.8% of mammals. They suggested the level of threat to amphibians is undoubtedly much greater than previously thought because 1,300 species (22.5%) were too poorly known to assess, i.e., Data Deficient, as compared to only 0.8% of birds and 5.3% of mammals. Some of the declines were traced to the fungal disease known as chytridiomycosis caused by Batrachochytrium dendrobatidis (or Bd). Arizona amphibians have not escaped Bd, although the infection rate at some locations is relatively low (Sigafus et al. 2014). The first global assessment of extinction risk in reptiles was presented by Böhm et al. (2013). They used a representative global sample of 1,500 reptiles. 59% of the species in the assessment ranked as being of Least Concern; 5% were considered Near Threatened; 15% were ranked as Threatened (Vulnerable, Endangered, or Critically Endangered); and the last 21% as Data Deficient. The authors estimated the true percentage of threatened reptiles in the world to be 19% (range: 15-36%). Another 7% of species were estimated as Near Threatened (range: 5-26%). Of the 223 species categorized as threatened, about half (47%) were assigned to the Vulnerable category, another 41% Endangered, and 12% regarded as Critically Endangered. By habitat, threat estimates found 19% of terrestrial species threatened, while 30% of marine and freshwater species were estimated as threatened. The percentage of threatened species varied greatly among higher-level taxa. Three of four crocodilian species and 52% of freshwater turtles were estimated as threatened. As a whole, turtles were equally spread among Red List categories, with 51% of species estimated as threatened and another 22% assessed as near threatened. In contrast, only 21% of lizards and 12% of snakes were in the threatened categories. Sinervo et al. (2010) used modeling and data from numerous studies in Mexico to assess extinction and extirpation (local extinction) likelihood for lizards. Many of these species are also found in Arizona. They estimated that about 40% of lizards would be extirpated and 20% of the lizards, worldwide, would be extinct by

22 Arizona and its Herpetofauna The number of endangered and threatened species listed by the federal government by county in the USA. Arizona has its share of threatened species because of its complex topography and landscape history. Many of the currently listed threatened species inhabit the rugged sky island mountain ranges. Each range, like the iconic Santa Rita Mountains, stands alone surrounded by desert flatlands, an island in the sky. The mountains are so high they span climatic zones from hot, dry desert to moist forests at higher altitudes. The sky islands are refuges where human impacts have been relatively small. Streams form at the high elevations and support fish, frogs, snakes, and nesting habitat for birds, and mammals. Many of these species have restricted distributions and narrow habitat requirements. Once they are gone, they are gone forever. While Arizona supports much intact habitat, fragmented and degraded habitats are increasing. Much of this is due to industrial-scale mining. Old abandoned mines perforate the sky islands. However, new grandiose plans from current want-to-get rich schemers see the sky islands as a source of cash instead of its natural wealth of biodiversity. Trading endemic biodiversity for short term gains that benefit a few is not what most of us want for future generations. Mining impacts local ecosystems in numerous negative ways. The damage goes far beyond the hole that is created in the ground. The toxic tailings blanket the land surface around the hole. The noise from the mining operation drives away wildlife and makes the area unfit for human habitation. And then there is the damage to the water supply. Mining operations pump vast amounts of water out of the aquifer, lowering the water table in an already waterstressed environment. Streams and tanks dry up and valuable wildlife habitat is lost. In Arizona, 20 of 35 surviving native fish species are endangered and one is already extinct. Contamination of the water with heavy metals also becomes a cost society has to bear from mining. Currently, mining operations are planned for the Santa Rita and Patagonia mountains. The fight to maintain the wealth of biodiversity needs to be generational. People who understand and appreciate biodiversity will not destroy it. Advancing knowledge of amphibians and reptiles is the purpose of this book. It is a small part of developing the appreciation and values needed to stop the get-rich-quick folks. Of course there are other threats to Arizona s biodiversity, not the least of which is the changing climate. The red areas on the map will become more intense as species become threatened and disappear. 7

23 Arizona s Amphibians & Reptiles The map above, from the Nature Conservancy, shows the ecoregions of the American West. There are 825 unique ecoregions in the world, Arizona has five of them. These are analogous to ecological neighborhoods that share similar habitat. Perhaps a better definition is a large area of land or water with a geographically distinct assemblage of species, natural communities, and environmental conditions. Ecoregion boundaries are not fixed; instead they encompass transition areas where ecological and evolutionary processes interact. Tropical forests and coral reefs harbor the most biodiversity and are often the traditional targets of conservation organizations. However, unique nature occurs everywhere. Sub-tropical, temperate and boreal regions have deserts and mountain chains along with unique species found nowhere else on Earth. The biosphere, the layer of the Earth that supports life and all of nature, is at risk of being damaged, so that it will not support the diversity of life as we know it. 8

24 Arizona and its Herpetofauna Worldwide, about 30% of amphibians and 20% of reptiles are estimated to be at risk of disappearing, making these two groups the most endangered vertebrates. Human-produced toxins, climate change, invasive species, habitat destruction, and disease are the major factors contributing to the decline of amphibians and reptiles. Unfortunately, amphibians and reptiles are not nearly as well-studied as birds and mammals, and the number of undescribed species is substantial. Arizona had about 8 million people in By 2030, it is estimated to increase to just over 10 million inhabitants. Human population growth will certainly result in less habitat for the fauna and more damage to ecosystems. Minimizing the damage to biodiversity is important. On behalf of the Southwest Partners in Amphibian and Reptile Conservation, Jones et al. (2016) provided habitat management guidelines to help land managers and private and public entities reduce the impact of human influence on the habitats and populations of native species. They also provided a list of species or groups having the greatest conservation need. Similarly, the Arizona Game and Fish Department maintains a list of Species of Greatest Conservation Need. This Book and Others This book is intended to provide an overview of the natural history of Arizona s herpetofauna and, secondarily, to act as a field guide. Several field guides are available. Brennan and Holycross 2006 A Field Guide to Amphibians and Reptiles in Arizona is an excellent book for identification. For people just wanting to know about rattlesnakes, there is the two-volume Rattlesnakes of Arizona (Schuett et al., editors). For lizard enthusiasts there is Lizards of the American Southwest (Jones and Lovich, editors). Tom Brennan s online Field Guide to the Amphibians and Reptiles of Arizona is a source of information with excellent illustrations. Another good web source for some Arizona species is Gary Nafis California Herps: A Guide to the Amphibians and Reptiles of California. The Tucson Herpetological Society s website, includes a list of species found within a 100-mile radius of the city. Their accounts are packed with useful, up-to-date information. With a smartphone, these websites can be accessed from anywhere there is cell service, making them a valuable tool in the field. In this volume, I have hopefully added natural history information not immediately available from these web sources and provided some clues to the identification of the species you may have at hand. All linear measurements are in millimeters and give total lengths for amphibians and snakes, body lengths for salamanders and lizards, and shell lengths for turtles. They provide the maximum known size, the size at metamorphosis for amphibians, and the size at hatching or birth for reptiles. I have tried to avoid the rigid field guide formats by not following a specific outline for each account and by adding historical, scientific, and personal observations to accounts. 9

25 Arizona s Amphibians & Reptiles The map above plots the average annual precipitation contours from NOAA. Precipitation is important to all organisms because it influences the amount of photosynthesis (the amount of food that is produced) at a given locality. Areas with high food production tend to have greater biodiversity. While wet areas may have a greater diversity of organisms than deserts; desert biodiversity is unique, adapted for life in dry, lowproduction areas and certainly worthy of conservation. The next time you hear someone say it s a wasteland of sand and rocks, remind them of the unique life forms that have evolved in that waste land and survive there and nowhere else. Some of the traits used to identify species are shown in the six appendices at the back of the book. Abbreviations used include the following: ASL = above sea level, MYA = millions of years ago, SVL = snout-vent length or body length; mm = millimeters, cm = centimeters, ha = hectare. Map localities come from two online databases, Vertnet ( and GBIF ( In both cases, the localities are documented by preserved specimens. Some of the maps include published localities from research papers, localities from other field guides, and in a few cases, localities from personal observations. I have not attempted to obtain every locality ever published, or represent every museum specimen in every collection. In some instances, the species 10

26 Arizona and its Herpetofauna may be more widespread than is indicated by the map. In other cases, the maps may suggest that a species is found at numerous localities when in fact it has been extirpated from many of those sites. The maps were constructed with ESRI s ArcView GIS software. Species that have had recent name changes or multiple common names have those names noted at the start of each account. These are not exhaustive lists, but names likely to be encountered in other field guides, such as Stebbins (2003). Common and scientific names usually follow Crother et al. (2017) with some exceptions. Two major exceptions are the hylid frogs and the rattlesnakes, where we follow the arrangements of Duellman et al. (2016) and Schuett et al. (2016) respectively. Discussion of subspecies occurs within the species accounts. Some subspecies may be destined to become full species, others will fade into history. They can be confusing and are human constructs, not necessarily natural units, but they are important because they are frequently used as units for conservation. A Note on Frog Calls Anurans (frogs and toads) are conspicuous because of their vocalizations. The calls we usually hear are advertisement calls for reproduction, but anurans also call to express aggression, defense, and more subtle social situations. The idea that frogs and toads make multiple kinds of calls is only a few decades old. This is a summary of some of them and follows Toledo et al. (2015). Anurans usually have external fertilization and the term mating is not appropriate. Instead, herpetologists use the term amplexus for the embrace that allows females to release their eggs and the males to fertilize them. The advertisement call, may be a simple one note call or a more complex composed of a series of identical notes or a combination of one or more notes or note groups with different acoustic structures. They are usually transmitted through the air, but some species call while submerged. Males usually make advertisement calls, but in some species only females call. In Arizona anuran males make these calls to attract females for reproduction. The amplectant call is made by males during the amplexus and it may stimulate the female to release eggs. It is accompanied with muscular movements. The release call is emitted by males and females when a pair is in amplexus or almost in amplexus and is touched by another male. The call is often accompanied with small vibrations, and it signals that the individual is not a female or is an unreceptive female. 11

27 Arizona s Amphibians & Reptiles The post-oviposition male release call is often similar to the advertisement call, but softer. It is emitted by an amplectant male just after egg laying and before the male releases the female. It has not been well studied. The rain call is emitted during precipitation events. It may indicate male excitement that may or not be related to the reproductive season. This is one of the less-studied anuran calls. The territorial call is the most common aggressive call. It is made by males defending a specific resource inside a territory. The resource may be a specific site used for calling, egg laying, retreat, or feeding. This call results in males spacing themselves while calling. It is made in the presence or absence of a nearby male, but the more males in a given area, the more frequent the call. The encounter call is emitted by males that are in close proximity, when the intruder has already entered the resident s territory. This call generally precedes physical combats (fights). The fighting call is emitted during the physical combat between two males. It is short in duration and has a lower frequency and lower volume than other aggressive calls. The distress call is emitted when a frog or toad is seized by a predator or when running from the predator, and it is often made with an open mouth. It may frighten potential predators and attract other animals that may distract the predator. 12 A pair of Couch s Spadefoots in amplexus.

28 Arizona and its Herpetofauna A Great Plains Toad calling from a flooded ditch in Cochise County. 13

29 Arizona s Amphibians & Reptiles Amphibia Amphibians are tetrapods that lay eggs lacking the embryonic membranes found in reptiles, birds, and mammals. They are ectotherms and often thermal conformers. Eggs and larval stages are usually aquatic, and the larvae undergo metamorphosis to develop into miniatures of the adults. The name amphibian is derived from a Greek word meaning double life, a direct reference to the fact that most species spend part of their life in water and part on land. Most amphibians have external fertilization; the eggs develop in the water outside of the female s body; and the larvae are free-swimming when they hatch. Despite this, many amphibians have evolved some type of parental care. Anurans are commonly called frogs and toads. Members of the group share the following characteristics: A short vertebral column, making their bodies short, and often stout. Adults lack a tail. The rear legs are longer than the forelimbs, which facilitates jumping and hopping. Many have an aquatic larval stage (a tadpole) before they are sexually mature. Most have permeable skin that can be used to exchange gases between their bloodstream and the atmosphere. Adult frogs are carnivorous and most prey on invertebrates. Many species vocalize to attract a mate, defend a territory, or send an alarm to other frogs nearby. Salamanders and newts form the order Caudata. Arizona is home to one recognized species. Salamanders are distinguished from other amphibians (frogs and caecilians) by the following: The presence of a tail in all larvae, juveniles, and adults. Limbs about equal in size and set at right angles to the body in most groups. Internal fertilization of their eggs. Most salamanders have a life cycle with an aquatic larva with external gills and a terrestrial adult that exchanges gases with the atmosphere via lungs and moist skin. Salamanders are carnivorous in all stages of their life cycle. 14

30 Amphibia - Spadefoots Spadefoots The Spadefoots (family Scaphiopodidae) are toad-like anurans. Two genera contain eight Western Hemisphere species. They mostly occur in deserts and dry grasslands from southern Canada southward to southern Mexico, but two species occur in the moister environments of the southeastern United States. Spadefoots live underground for ten months a year. The low frequency sound from thunder or rain pounding the ground stimulates them to emerge from their burrows during heavy rains. A small, black mass of keratin on their heel the spade is the basis for their name. The spade is used for digging, removing soil from directly below the toad. Spadefoots dig burrows backward using their hind legs and feet. They excavate the soil from under themselves and sink into the hole, leaving no trace that they lie beneath. The presence of the spade, combined with a horizontal pupil will separate Arizona members of this family from other families of anurans. The two North American genera, Scaphiopus and Spea, separated 29 to 20 million years ago (MYA) between the Oligocene and the Miocene, based on the fossil record. The species within Spea diverged within the last six million years. The relatively recent diversification of Spea compared to that of Scaphiopus may explain why it is more difficult to distinguish the species of Spea than those of Scaphiopus. Spadefoots are found over most of the state and are considered species of least concern when it comes to conservation. However, human activity subjects them to a variety of environmental stressors. Habitat fragmentation and pesticides are of particular concern. The use of irrigation technology has destroyed some of the areas where spadefoots once lived. Additional threats come from pesticides. Dinehart et al. (2010) found the pesticide Roundup Weathermax to be moderately toxic to spadefoot tadpoles. Spadefoots will also emerge prematurely from their underground retreat because of low frequency sounds from motors, a phenomenon that can be fatal to all of the spadefoots that emerge when humidity and precipitation are almost non-existent. The two genera can be separated from each other based on the condition of the skin covering the skull. Scaphiopus has the skin fused to the skull, while Spea does not. Scaphiopus has a sickle-shaped spade, while the spadefoots in the genus Spea have a wedge-shaped spade. Four of the known spadefoot species occur in Arizona: Couch s Spadefoot, Scaphiopus couchii; the Chihuahuan Desert Spadefoot, Spea multiplicata stagnalis; the Plains Spadefoot, Spea bombifrons, and the Great Basin Spadefoot, Spea intermontana. Arizona spadefoots usually lack a parotid gland, a trait that distinguishes them from the true toads (Family Bufonidae). In Arizona, sexual size dimorphism is apparently absent. 15

31 Arizona s Amphibians & Reptiles Couch s Spadefoot, Scaphiopus couchii Baird, 1854 Adult males are 48 to 70 mm SVL; adult females are 50 to 87 mm SVL. Body size at metamorphosis is 9.5 to 12.9 mm. Females are mottled with dark reticulations, while males are more uniform in color. The dorsum has dark brown to black mottling on a yellow to green background; the belly is bright white to a dirty cream. Rear limbs are short. A black, sickle-shaped spade on the bottom of each rear foot, the lack of a raised area between the eyes, widely spaced eyes, and an elongated profile will distinguish this species from the other spadefoots. Tadpoles are small, black-brown with bronze flecking; they reach 25 mm in total length. The call sounds like the anxious bleating of a lamb, lasting 0.25 to 1.75 seconds. The species occurs from Texas and southwestern Oklahoma to New Mexico and Arizona, into extreme southeastern California, and southward to Nayarit, Zacatecas, and Queretaro, Mexico, as well as in much of Baja California, Mexico. A molecular study compared the Arizona and Baja populations of this spadefoot and found them to be genetically distinct. A range-wide genetic study of this toad is likely to turn up multiple cryptic species. Disjunct populations in southeastern Colorado, as well as east and north-central Arizona and southeast California suggest it was once more widespread. Within Arizona, Couch s Spadefoot occurs in most of the southern third of the state, with the disjunct populations previously mentioned. They range in elevation from sea level to 1,800 m. Most breeding is confined to July and August, but it may start earlier and last longer in some years. After the first monsoon storms fill temporary pools and the initial reproductive event occurs, secondary breeding events follow with subsequent rainfalls. Spadefoots may be sexually mature at two or three years of age, and most individuals sampled at breeding sites are five-to-ten years old. Males call from shallow water and arch their head and body upward, exposing a bright white gular region. Females are attracted to the sound and possibly to the ambient 16

32 Amphibia - Spadefoots Breeding in Couch s Spadefoots is triggered when summer rainfall fills temporary pools; it is synchronous and follows heavy rains. After the first breeding event, second and third events may occur with subsequent rainfall. The secondary events usually involve a smaller number spadefoots. Breeding occurs in temporary pools that form in playas, tanks in rocky streambeds, isolated pools in arroyos, stock tanks, and road side ditches. These ephemeral pools cause the tadpoles to be in continual risk of drying out. 17

33 Arizona s Amphibians & Reptiles light reflecting off the male s vocal sac. Spadefoots have a pelvic amplexus position, with the male clasping the female around the waist. As she releases her eggs, the male releases sperm and the eggs are deposited on vegetation, or simply left in the water if the pools lack plants. A female may lay more than 3,000 eggs per clutch. The embryos develop rapidly, and tadpoles may emerge in less than 24 hours and began to feed on detritus. Adults excavate their burrows and spend eight-to-ten months 20 to 90 cm below the surface. The burrows are relatively close to breeding sites. The time spent below the surface may be greatly extended during droughts that span years. They survive extended dry periods by reducing water loss with several layers of shed skins and accumulating concentrations of urea in their body fluids to create an osmotic gradient and pull water from the soil into their body. Couch s Spadefoots have been observed sitting in the opening of their burrow, waiting to ambush prey. They feed during rainy and humid nights. During metamorphosis, the toadlets have difficulty capturing prey until their tail is absorbed. Once the tail is gone, they become effective predators, feeding day and night until they are forced to burrow by lower humidity and the absence of surface water. Adults can ingest up to 55% of their body weight in food (mostly termites) and enough calories to support themselves for a year at a single feeding (Dimmitt and Ruibal, 1980). Tadpoles have numerous predators, including larval beetles, larval tiger salamanders, carnivorous Mexican Spadefoot larvae, mud turtles, grackles, and skunks. Juvenile and adult frogs are prey for a variety of larger amphibians, snakes, birds, and mammals. When confronted by a predator, adults pull in their limbs, close their eyes, flex their head downward, and secrete noxious chemicals to deter the predator. These molecules may cause sneezing and skin irritation in some humans. Plains Spadefoot, Spea bombifrons Cope, 1863 Adult males reach 64 mm SVL; adult females reach 62 mm SVL. Body size is sexually dimorphic in some populations but not others, usually with larger females. Tadpoles 18

34 Amphibia - Spadefoots are tan, brown, or gray and have a transparent quality. The eyes are dorsal. Tadpoles can reach 65 mm in total length, but often metamorphose at 41 to 52 mm at 13 to 14 days of age. The call is a snore-like rasping lasting 0.5 to 0.75 seconds. The Plains Spadefoot differs from other spadefoots by having a bony boss (raised area) between the eyes and dorsolateral stripes. It has a gray-brown or green-brown dorsum, with irregular dark markings; the belly is white. Its skin has some tubercles. Its eyes have a golden iris and elliptical pupils; the eyelid width is greater than the space between them. The bottom of each rear foot has a wedge-shaped spade. Breeding males have keratinized nuptial pads on their first three digits. Superficially it is most similar to the Chihuahuan Desert Spadefoot, with which it hybridizes in the four corners area and southeastern Arizona. These hybrids may have a slight bony boss between the eyes. The species occurs from Alberta, Manitoba, and Saskatchewan in Canada, as far east as Missouri and eastern Oklahoma, and southward to northwest Texas and Chihuahua, Mexico. Isolated populations occur in South Texas and Mexico. It enters Arizona in the northeast and southeast corners of the state. It is associated with loose, well-drained soils. The associated vegetation ranges from mixed-grass prairie, shrubland, and floodplains, to desert grasslands. They range in elevation from 500 to 2,440 m. Breeding events are correlated with peaks in precipitation. Droughts may cause populations of spadefoots to skip reproduction for one or more seasons. However, individuals may breed more than once in a single year when conditions are favorable. Choruses can be heard at considerable distances, and this stimulates both sexes to move to the breeding ponds. Larger choruses attract more individuals of both sexes. The combination of preferences for temporary pools and sandy soils limits the number of potential breeding sites. The Plains Spadefoot depends upon less permeable soils within sandy habitats where longer-lasting, yet, temporary, wetlands form. Breeding ponds include flooded fields, roadside ditches, temporary upland ponds, semi-permanent pools, oxbow lakes, sloughs, marshy depressions, wet pastures, river backwaters, pools of water around construction sites, and ditches. Single clutches contain 10 to 250 eggs, but females lay multiple clutches that may total 2,000 eggs per season. The egg mass is spherical and attached to submerged vegetation. Soil particles often stick to the egg mass and camouflage the eggs from potential predators. Like other spadefoots, egg development is temperature-dependent, and eggs hatch in about two days. Temperatures below 10 C and above 34 C tend to be lethal for eggs and larvae. Plains Spadefoot females that live with Chihuahuan Desert Spadefoots alter their mate choice when they are using the same deepwater breeding sites. Plains Spadefoot females seem to prefer to mate with male Chihuahuan Desert Spadefoots, and apparently the hybrid offspring has an advantage over the purebred offspring in that more of the hybrid tadpoles become carnivorous (Pfennig 2007). Predators of tadpoles include water scavenger beetle larva, Triops shrimp, gartersnakes, and cannibalistic tadpoles. Predators of adults include rattlesnakes, hawks, and rodents. 19

35 Arizona s Amphibians & Reptiles Great Basin Spadefoot, Spea intermontana Cope, 1863 Adults can reach 63 mm SVL, but are usually 40 to 59 mm SVL, with a mean of 48 mm SVL. Tadpoles transform at 85 mm. As with many other anurans, tadpoles may exceed the size of the adult body length. Skin is mostly smooth with some tubercles, and there is a raised area between the eyes. Eyes have an elliptical pupil and a yellow-to-gold iris with black reticulations. The dorsum is tan to brown with longitudinal stripes. The bottom of each rear foot has a wedge-shaped spade. It is a plain-looking anuran with a distribution that does not overlap with other species of spadefoots. The call is a low-pitched, hoarse snore, wa-wa-wa, that lasts seconds and is repeated. The species occurs from south-central British Columbia, southward to eastern Washington, Oregon, and California and westward to Nevada, Utah, Idaho, Colorado, and southwestern Wyoming. It enters the northwest corner of Arizona. Like the other spadefoots, the Great Basin Spadefoot uses sagebrush and bunchgrass prairie, alkali flats, semi-desert shrublands, pinyon-juniper woodland to open ponderosa pine communities, and spruce-fir forests up. They range in elevation from 1,200 to 2,800 m. They will also use agricultural and riparian areas for reproduction. While the other Arizona spadefoot species breed with the first monsoonal rains, the events that stimulate the Great Basin Spadefoot migrations are not as clear. Surface activity occurs during the first warm evenings of spring, and while it is most commonly encountered during an evening rain, diurnal activity is known. Reproduction occurs from April to July and is variable from year to year and not synchronized. Eggs require two-to-four days to hatch, and metamorphosis takes another 36 to 60 days, depending upon temperature. Clutch size is between 300 to 1,000 eggs. The tadpoles are omnivorous, feeding on detritus and carrion, including the carcasses of Great Plains Spadefoots, and they prey upon the embryos of Woodhouse s Toad. The tadpoles may also be cannibals. When tadpoles of the Plains Spadefoot and the 20

36 Amphibia - Spadefoots Great Basin Spadefoot occur together, they produce different morphs (Pfennig and Murphy, 2002). The Plains Spadefoot increases the number of carnivorous tadpoles that feed mostly on shrimp, while the Great Basin Spadefoot produces few carnivorous tadpoles and increases the number of omnivorous tadpoles that feed mostly on detritus. Males mature at a slightly smaller size than females, probably in the first or second year after metamorphosis. Females are probably not sexually mature until the second or third breeding season after metamorphosis. Predators on Great Basin Spadefoots are numerous and include trout, gartersnakes, and rattlesnakes. They have an odor that has been likened to popcorn or roasted peanuts. If the skin secretion makes contact with a mucous membrane, the sticky skin secretions can cause a burning sensation. Mexican Spadefoot, Spea multiplicata Cope, 1863 Adults may reach 65 mm SVL; usually they are mm SVL and average 47 mm SVL. Males sexually mature at two-to-three years, while females probably take more time to reach maturity. On average, males are slightly smaller than females. Tadpoles are olive to gray and tend to be transparent. The eyes are dorsal and positioned close together. Larvae reach 74 mm. The dorsum is a uniform brown to dark gray with small dark spots or blotches and scattered red-tipped tubercles; dorsolateral stripes are absent. The iris is a slightly variegated copper color. A short wedge-shaped spade is present on each hind foot. Male vocal sacs appear as a dark, heavily pigmented area on the throat. Superficially, it is similar to the Plains Spadefoot, but has red tubercles behind the ear and lacks the bony boss. The red tubercles may confuse it with the Red-Spotted Toad, but the spade and lack of parotoid glands distinguish it from that species. The call is a metallic snore that is a long trill that lasts 0.75 to 1.5 seconds. One author described the call as a loud purr of a cat with the metallic sound of grinding gears. 21

37 Arizona s Amphibians & Reptiles The species occurs from western Oklahoma to Arizona and southward to Guerrero and Oaxaca, Mexico. The Chihuahuan Desert Spadefoot, Spea multiplicata stagnalis occurs in the eastern half of Arizona and uses a wide range of arid and semi-arid habitats, as long as breeding pools are available. They are associated with sandy or gravel soils in semi-desert grasslands, sagebrush flats, semi-arid shrublands, river valleys, and agricultural land. They range in elevation from 300 to 3,800 m. In Arizona, adults are subterranean most of the year, coming to the surface in July with the monsoon rains, and then returning to their burrows in September. Eggs are deposited in clusters on plant stems or rocks and incubate for 14 hours to six days depending on temperature. However, most hatch in less than 48 hours. Clutches average about 1,000 eggs. Chihuahuan Desert Spadefoots have two tadpole A male Couch s Spadefoot calling from ditch. The spadefoot is hidden from view by vegetation, but the sound and possibly the bright white vocal sac may attract predators. 22

38 Amphibia - Spadefoots morphs: a carnivorous morph and an omnivorous morph. The carnivorous morph feeds mostly on fairy shrimp (Anostraca sp.), while the omnivorous morph feeds on detritus, algae, and the occasional fairy shrimp. Carnivorous morphs have a broad head, large jaw muscles, a short gut, and rapid development. They occur in rapidlyshrinking pools with abundant fairy shrimp and low levels of organic debris. As might be expected, carnivorous larvae develop more rapidly than the omnivores and transform at a smaller size and with less body fat than the omnivorous morph. A large body at metamorphosis is a survival advantage. Thus, there is a trade-off between the carnivorous morph s small-body-size advantage in rapidly drying pools and the omnivorous morph s post-metamorphic advantage in pools that do not dry up. Interestingly, being a carnivorous or an omnivorous morph is plastic, and the tadpoles can change their feeding strategies based on the available food supply. The factors inducing a tadpole to become carnivorous were experimentally studied by Levis et al. (2015). They reared tadpoles on different diets (detritus, shrimp, Chihuahuan Desert Spadefoot tadpoles, and Couch s Spadefoot tadpoles) and found that diets containing Couch s Spadefoot tadpoles produced more carnivorous Mexican Spadefoots than diets without them. Couch s Spadefoot tadpoles apparently make excellent food for the carnivorous Chihuahuan Desert Spadefoot tadpoles. Chihuahuan Desert Spadefoots give off noxious secretions, which become airborne and have a smell that has been described as somewhat like pungent peanuts. These fumes can be a strong irritant to humans. When one of us (LLCJ) first moved to southeastern Arizona, he went road riding with three friends one rainy summer night. A single S. multiplicata was temporarily collected for photo opportunities, and within minutes the driver and all the passengers had symptoms, including sneezing, coughing, burning and watering eyes, itching, and runny noses. Needless to say, the spadefoot was released shortly thereafter. Everyone washed up, and the car was left to air out for a while. It was an impressive defense for such a small anuran and interesting how the different passengers had different reactions. 23

39 Arizona s Amphibians & Reptiles Salamanders in Arizona There is one salamander species known from the state, the Western Tiger Salamander, Ambystoma mavortium. However, there is circumstantial evidence that one or possibly two other species may occur in Arizona. Lungless Salamanders (family Plethodontidae) are widespread in the eastern US but less common in western North America. However, salamanders of the Isthmura bellii complex are widespread in central México. They are the largest, terrestrial, lungless salamanders with distinctive coloration usually composed of a black background color with bold red-orange marks on the dorsum. Most of these salamanders live above 700 m in pine-oak forests. The genus is of biological interest because, like many high-altitude vertebrates, it is thought to have direct development, with the females giving birth to young instead of laying eggs, although this needs confirmation. Most of the members of Isthmura are listed as vulnerable or critically endangered by the IUCN. Bell s False Brook Salamander was first described by Gray (1850), as Spelerpes bellii. In a review of the lungless salamander family Plethodontidae, Dunn (1926) wrote: United States: Arizona: Ft. Whipple 3 (United States National Museum, uncataloged, now lost). Dunn suggested that there were three specimens of this salamander in the Smithsonian from Ft. Whipple, Arizona but the specimens had been lost. After Gray s description, the salamander was moved to the genus Geotriton, then to Oedipus, then to Bolitoglossus, then Pseudoeurcyea, and most recently, Rovito et al. (2015) moved these salamanders to Isthmura. In 1964 a population of what was then called Pseudoeurycea belli was discovered near Yecora, Sonora. This Sierra Madre Occidental locality is about 880 km (550 mi) northwest of the nearest known localities for the species in Nayarit and 770 km (480 mi) southeast of Dunn s lost USNM specimens from Fort Whipple, Arizona. In 1968, Lowe et al. named the new subspecies P. b. sierraoccidentalis for the Sonora-Chihuahua population, based upon the reduced dorsal blotches of the new subspecies. In 1987, Tom Van Devender and Peter Holm observed four adults of P. b. sierraoccidentalis in the Ocampo area of Chihuahua, which became the second locality for the subspecies (Bezy et al. 2004). This left P. bellii in isolated populations in central Mexico s Sierra Madre Oriental in the states of Tamaulipas, Nayarit, Zacatecas, and Guerrero. These were divided up into several of the extant seven species by Parra-Olea et al. (2005). The specimens Dunn noted likely represented an undescribed species. It may still live in the high-altitude pine-oak forests around Ft. Whipple and simply has been undetected by herpetologists or the population could have be extirpated due 64

40 Amphibia - Salamanders in Arizona to development or natural causes. The question of an Arizona species of Isthmura remains unresolved. There is another possible plethodontid salamander in Arizona. An alien population of the Large-Blotched Ensatina (Ensatina eschscholtzii klauberi) may have been established in a montane region of Arizona. One of us (GN) was told by an Arizona Game and Fish biologist that the salamanders were put there illegally in 1980 by someone who wanted to save the subspecies. Mole Salamanders Mole Salamanders are some of the largest terrestrial salamanders of North America. The family ranges from southern Canada to the Mexican Plateau and contains 37 species in two genera. Fossils are known from the Oligocene, about 37.3 MYA, but the molecular clock suggests the family split from its Eurasian sister family, the Salamandridae, 167 MYA. Most mole salamanders have courtship and breeding in the late winter or spring, but a few species reproduce in autumn. Some species are polyploids, having evolved by increasing the number of sets of chromosomes. Larvae may overwinter in ponds, and some species retain larval characters, such as external gills and tail fins into adulthood. These adults are larva-like and are known as paedomorphs or neotenes, and they can reproduce while retaining these larval traits. Tiger salamanders were first reported in Arizona when Hallowell described A. nebulosum in 1852 (1853). He initially gave the type locality as New Mexico, later revising it to the San Francisco Mountains of Arizona. Mole salamanders were rediscovered in Arizona s Parker Canyon in the Huachuca Mountains at an elevation of about 1,500 m ASL by Reed (1951), and their presence was later confirmed by Lowe (1954). The Sonoran Tiger Salamander, A. m. stebbinsi, is now considered a distinct subspecies based on molecular evidence. However, hybridization with the introduced Barred Tiger Salamander is causing some populations to lose their genetic identity. Note that the Western Tiger Salamander, Ambystoma mavortium, was long confused with the Eastern Tiger Salamander, A. tigrinum. As their common family name suggests, ambystomid salamanders spend much of their adult life underground in burrows. They may excavate these themselves or use burrows made by other animals. The Barred Tiger Salamander can exceed a total length 35 cm, and they are likely the longest terrestrial North American salamander. An individual can have up to six distinct morphs during its lifetime. The morphs are gilled adults, cannibalistic gilled adults, normal transformed adults, cannibalistic transformed adults, large transformed adults, and small transformed adults. The cannibal morph is known to occur in four of the subspecies and is characterized by a broad head, large skull, and an extra row of pre-vomerine teeth. Additionally, the cannibal morphs tend to reach a larger adult size than the other morphs. The presence 65

41 Arizona s Amphibians & Reptiles An adult Western Tiger Salamander. Larvae of this species are commonly used as bait in Arizona for non-native fishes, particularly largemouth bass. One estimate of the number of larvae sold along the Lower Colorado River from Lake Mead to the Mexican border, in 1968 was an astounding 2.5 million. The larvae were imported from other western states as well as Mexico. The bait industry has been practicing this since the mid-20 th century and has altered the native Ambystoma gene pool. 66

42 Amphibia - Salamanders in Arizona Paedomorphosis is a major evolutionary process that bypasses normal metamorphosis and allows larvae to become sexually mature and reproduce. In salamanders, paedomorphosis can be facultative with the paedomorphs retaining gills and remaining in the water and metamorphs dispersing overland. Marthiron et al. (2017) suggest the evolution of these developmental processes is driven by the costs and benefits of inhabiting aquatic versus terrestrial habitats. They tested the hypothesis that climatic drivers affect which transition the individual chooses and the difference across sexes because sex-ratio is biased in natural populations. In a laboratory experiment, they demonstrated salamanders metamorphosed at a higher frequency when water availability decreased and metamorphosed earlier when temperature increased in these conditions. All their responses were sex-biased with males being more prone to change phenotype than females. 67

43 Arizona s Amphibians & Reptiles of large and small morphs depends upon whether the breeding site is a seasonally ephemeral pool or a larger, more permanent body of water. The small morphs occur in the ephemeral pools, transform at a smaller size, and reach a smaller adult size. Reproduction occurs after rains trigger a migration from hibernation sites to breeding ponds. Depending on the subspecies, eggs may be deposited singly or in clusters. They may or may not be attached to structures, or on the substrate. Eggs hatch in 19 to 50 days, depending upon conditions at the breeding site. Age at sexual maturity depends upon temperature, food supply, water conditions, crowding, and subspecies. Time to maturation can be as short as five months in seasonally ephemeral pools or as long as three years in subalpine lakes. Different subspecies have different breeding seasons. Western Tiger Salamander, Ambystoma mavortium (Baird, 1850) Other names for this salamander include the Barred Tiger Salamander and Ambystoma tigrinum. Adult terrestrial morphs may reach 165 mm SVL. However, paedomorphs may reach 381 mm in total length. The dorsum is black with yellow bars or a black reticulated pattern with yellow in between. Some specimens may be a uniform brown. The ventral surface is black with some yellow. Color and pattern vary considerably with location. The head is broad and the snout rounded; the eyes bulge slightly from the head. The tail is laterally compressed. The species occurs from central and western Canada southward in the United States to Texas, California, Arizona, and New Mexico. However, it is mostly absent from the Great Basin deserts of Utah, Nevada, Oregon, and California. Isolated populations occur in central and eastern Washington. The systematics and taxonomy of this salamander are confused, so here we follow the traditional classification. Three subspecies of Barred Tiger Salamanders occur in Arizona, but only two are native. The Sonoran Tiger Salamander, Ambystoma mavortium stebbinsi (Lowe, 1954) occurs only in the San Raphael Valley between the Huachuca and Patagonia Mountains of southeast Arizona. 68

44 Amphibia - Salamanders in Arizona The Arizona Tiger Salamander, Ambystoma mavortium nebulosum Hallowell, 1852 is distributed on the Mogollon Plateau and the Colorado Plateau and adjacent New Mexico. In Arizona, the majority of populations are in the basins of the Little Colorado and Gila Rivers, both of which are tributaries of the Colorado River. The known populations are positioned, with rare exception, between these two rivers, and are probably more abundant in the Little Colorado drainage system than in that of the Gila. No populations of this race are known from south of the Gila River proper. The upper surface of its body has fewer than 25 (usually 10 to 20) yellow spots between front and hind limb insertions; the tail has 10 to 35 spots, and the belly is boldly patterned with yellow. It is likely that the Arizona Tiger Salamander is a hybrid between the Barred Tiger Salamander and the Sonoran Tiger Salamander. The Sonoran Tiger Salamander, Ambystoma mavortium stebbinsi, inhabits the San Rafael Valley of Santa Cruz County, Arizona and Sonora, Mexico, and Cochise County, Arizona. Molecular evidence suggests that the Sonoran Tiger Salamander evolved from a hybridization event between the Barred Tiger Salamander and the Arizona Tiger Salamander. The Sonoran Tiger Salamander displays changes in its dorsal pattern from the time it metamorphoses until it reaches old age. The ventral pattern is a uniform black with yellow slightly intruding from the sides. The populations in the San Rafael Valley and surrounding mountain ranges are at 1,418 to 1,897 m ASL. Habitat in the San Rafael Valley is primarily grasslands. The Sonoran Tiger Salamander uses cattle tanks to reproduce, although historically it used cienegas, which have mostly disappeared from its range. Discussing the Sonoran Tiger Salamander s future survival, Hossack et al (2017) wrote: Like many imperiled aquatic species in the southwestern USA, the loss of natural habitats free of invasive predators means that preventing further declines of the Sonoran Tiger Salamander may require sustained management. The ability to rank particular habitats according to their potential contribution to metapopulation recovery and growth would help inform management 69

45 Arizona s Amphibians & Reptiles options. For example, typical for studies of occupancy across a network of water bodies we implicitly assumed the ecological and management value of all subpopulations was equal, but we know this assumption is false. We suspect that long-hydroperiod ponds that support paedomorphs (i.e., salamanders that breed in the aquatic form) are the most stable subpopulations, but these habitats are also the most likely to support invasive predators. In contrast, ponds that dry frequently might have a small number of larvae when surveyed and thus are considered occupied, yet they might contribute little to the metapopulation. Incorporating information on abundance of imperiled species and their threats would provide much richer information on which to base population viability assessments and other risk projections that can be used to rank management options and design habitats for future climate resilience. The future survival of the Sonoran Tiger Salamander is dependent on livestock tanks. Standing water from January through June is the most important habitat characteristic. It ranges in elevation from 1,418 to 1,897 m. Adults emerge from their underground refuge and migrate to water for breeding. Adults that retain their gills remain aquatic and breed in the larval body form. Reproduction occurs from January to May and rarely after summer rains. Females lay 200 to 2,000 jellycoated eggs in water; they require 2 to 4 weeks to hatch. The larvae feed on a variety of aquatic fauna, and the adults feed on most any animals they can overpower, including worms, mollusks, arthropods, fish, other amphibians, and occasionally small mammals. At least three of the 18 colonies described in 1988 were extirpated. However, from 1994 to 1999, half of the 53 populations now known were discovered. Possible threats include disease, predation by introduced non-native fish and bullfrogs, illegal collection for bait by anglers, habitat destruction, reduced fitness due to inbreeding, and increased probability of random extirpation characteristic of small populations. The State of Arizona made the collection of tiger salamanders in south central Arizona illegal because of the difficulty in identification of the three subspecies known from the state and for the potential genetic damage to the native Sonoran Tiger Salamander. 70

46 Reptilia Reptilia Reptiles are tetrapods, animals with four limbs, or animals that are descended from animals with four limbs. Turtles, crocodilians, snakes, amphisbaenians, lizards, and the tuataras compose the living reptiles. Each of these has been considered an order of living reptiles. The amphisbaenians are now known to be lizards. Additionally, birds have now been added to the Reptilia because they are descended from reptiles. Adding them makes the Reptilia a clade (a group of organisms that share a common ancestor and that ancestor). Reptiles are oviparous (egg-laying) or they give live birth (viviparous). Unlike amphibians, reptiles do not have an aquatic larval stage. Reptiles (or their ancestor) evolved the land egg, which includes membranes for protection and nourishment of the embryo. Many viviparous reptiles feed their embryos through placenta-like structures similar to the placenta in mammals. Some reptiles also provide parental care for their hatchlings or neonates. Living reptiles range in size from a tiny gecko that is only 17 mm long to the saltwater crocodile, which may exceed 6,000 mm in length and weigh over 1,000 kg. Arizona reptiles include the Chelonia and the Squamata. Chelonia: Turtles and Tortoises The name turtle is commonly applied to marine species, but also as a common name for all members of the Chelonia. Terrapin is used for semi-aquatic chelonians, and tortoise is used for land-dwelling chelonians. Turtles have rigid, toothless beaks and use their jaws to cut food. The upper shell of the turtle is called the carapace; the lower shell is the plastron. They are joined by bony bridges. The vertebrae are fused to the shell. Turtles ventilate their lungs by pumping air in and out and by moving their limbs in and out of the shell; they exhale by contracting abdominal muscles to force gases out of the lungs. Most turtles are omnivores, but some tend to be more herbivores while others are carnivores. Turtles are among the most endangered reptiles. 71

47 Arizona s Amphibians & Reptiles Squamata: Lizards and Snakes Squamates are Arizona s most diverse group of reptiles. They have the ability to shed their skin in one piece or in large pieces as they grow. They may have four, two, or no limbs. Many Squamates have evolved venom for killing prey. They have a uniquely divided double penis (hemipenes). They are covered with scales. Squamates have a mobile quadrate bone. Most squamates have teeth. 72

48 Reptilia A pair of Yarrows Spiny Lizards bask in the mid-morning sun along a forested trail. 73

49 Reptilia - Whiptails Whiptails Teiids (family Teiidae) are medium to large lizards distributed in the Western Hemisphere. There are 16 genera with 151 species. The family reaches its greatest diversity in South America. Only one genus occurs in Arizona, Aspidoscelis. About 11 species of whiptail lizards occur in the state, and one appears to be introduced. The whiptails have the upper surface of their body covered with tiny granular scales, while the belly is covered with large plate-like scales in eight longitudinal rows. They are fast-moving when escaping a potential predator, but walk with a jerky gait, as they occasionally pause, raise one foot off the ground, and shake it. Their head is in constant motion, moving from side to side, and they stick their head under leaves or other debris piles looking for food. All feed on arthropods. Some Arizona species are all-female populations that reproduce by parthenogenesis. These parthenogens evolve from sexual species (males and females present in the population) hybridizing. Many whiptails can be tricky to identify. Most Arizona species have a striped pattern that may or may not have spots. The number of stripes and the position of the spots are often key in identification. Whiptails are active diurnal foragers. Female whiptails lay small clutches of eggs, six or less. There is evidence that some high-elevation populations may have live birth or very short incubation times for their eggs. The North American whiptails were formerly placed in the genus Cnemidophorus, but have all been moved to the genus Aspidoscelis. Chihuahuan Spotted Whiptail, Aspidoscelis exsanguis (Lowe, 1956) Adults reach 100 mm SVL, the tail more than twice the body length. This is a large, all-female species with stripes and spots. Hatchlings tend to be black or dark brown with six pale stripes and sometimes a seventh, vertebral stripe on the anterior body. They lack spots between the stripes. If present, the seventh stripe is indistinct and incomplete. With age, pale spots form in multiple rows between the stripes, and they may fuse with the stripes to form a net-like pattern. The tail is gray-green. The ventral surfaces are white. 149

50 Arizona s Amphibians & Reptiles The Chihuahuan Spotted Whiptail is similar to the Gila Spotted Whiptail and the Sonoran Spotted Whiptail, but it has more light spots overall than either of these species. The spots are on the stripes, as well as between the stripes, and on the hind legs. The paravertebral stripes are wide and faded. This is a Chihuahuan desert species that inhabits canyons and riparian corridors in desertscrub to lower montane coniferous forest to at least 2,100 m. It reaches the western extent of its range in Arizona and occurs only in Cochise and Greenlee counties. The Chihuahuan Spotted Whiptail is an active forager, digging and searching under leaves and other debris in search of insects. Termites, grasshoppers, and beetles make up the bulk of its diet. Larger numbers of arachnids and lepidopterans are also taken. It has been observed ambushing, subduing, and consuming a tarantula (Aphonopelma sp). Activity starts when the soil temperature is between 26 and 30 C; The lizards seek shelter when the temperature exceeds 50 C. The preferred body temperature is about 39 C. This species likely evolved from three parental species in a two-stage hybridization event. In the first, the hybridization of the Texas Spotted Whiptail and an intermediate parent species mated and produced offspring. These offspring mated with another hybrid, formed between the Canyon Spotted Whiptail and the Little Striped Whiptail. Sexual maturity is reached at 63 mm. Females have ritualized courtship and copulation. Clutches of 1 to 6 eggs are laid. Like some other all-female species, males are occasionally found and are thought to be the product of a back cross with one of the parental lineages. 150

51 Reptilia - Whiptails Gila Spotted Whiptail, Aspidoscelis flagellicauda (Lowe & Wright, 1964) Adults grow to 99 mm, and the tail is more than twice the body length. It is a six-stripe, spotted whiptail. The juveniles lack spots and are dark coffeebrown or black. Spots develop with age in a single row between the stripes. The upper surface of the hindlegs is indistinctly mottled. Hatchlings and juveniles have an orange tint to the hind legs and tail, while adults have an olive-green tint with a blue tail, if unbroken. The belly is a uniform white. In the field, this species is difficult to distinguish from the Chihuahuan Spotted Whiptail and the Sonoran Spotted Whiptail. A wider, bolder neck stripe separates it from the Chihuahuan Spotted Whiptail, but not from the Sonoran Spotted Whiptail. Easily confused with the Sonoran Whiptail and the Chihuahuan Spotted Whiptail, it differs from both species in having two enlarged preanal scales and a vermiculated pattern on the dorsal surface of the thigh. It has fewer spots that the Chihuahuan Spotted Whiptail and well-defined stripes. Habitat used is Semi-Desert Grassland to Petran Coniferous forests from about 1,200 to 2,000 m along the Mogollon Rim. Isolated populations occur in the Santa Catalina and Chiricahua Mountains. The Gila Spotted Whiptail is active from April to October. Its average body temperature is about 39 to 40 C. Like the Chihuahuan Spotted Whiptail, it is the product of multiple hybridizations, which produced this allotriploid species. Females lay a small clutch of 2 to 6 eggs, which hatch into clones. Hatchlings are present in August and September. 151

52 Arizona s Amphibians & Reptiles The Sonoran Spotted Whiptail, Aspidoscelis sonorae shedding its skin. Whiptail lizards were formerly placed in the genus Cnemidophorus. Based on a combined analysis of mitochondrial DNA, morphology, and allozymes, one study determined that in the traditional sense whiptail lizards were paraphyletic and thus in need of nomenclature revision. Rather than place all cnemidophorine species in a single large genus (Ameiva), they proposed a split that placed the North American whiptails in the monophyletic genus Aspidoscelis. Under this arrangement, South American taxa remain in the genus Cnemidophorus. 152

53 Reptilia - Whiptails Little Striped Whiptail, Aspidoscelis inornata (Baird, 1859) Adult males reach 85 mm SVL. Females are slightly smaller. Both sexes have a tail more than twice the body length. This is a six- or seven-striped whiptail with no spots and a seven-striped whiptail with the middorsal stripe reduced in width and length. The dorsal pattern of seven yellow stripes is on a dark blue-gray to gray ground color without spots in between the stripes. The head, feet, belly, and tail are pale blue, and the color is more intense in males. It is most easily confused with the Pai Striped Whiptail, which has six stripes. The subspecies in Arizona is the Arizona Striped Whiptail, A. i. arizonae (Van Denburgh, 1986). Some authors recognize the Pai Striped Whiptail, A. i. pai, as a subspecies of A. inornata. Here, I retain it as a full species. The Arizona Striped Whiptail is known only from a few localities in Cochise and Graham counties in southeastern Arizona that have semi-desert grassland. Locations used by this species are higher in grass cover and lower in both mesquite and invader shrubs than sites occupied by the Desert Grassland Whiptail (Sullivan et al. 2005). The diet consists of termites, coleopterans, orthopterans, and larvae of these and other groups of insects. The smallest gravid female was 59 mm SVL. Mating occurs in the spring, and females lay one or two clutches of one to three eggs each season. The hatchlings have a total length of about 100 mm and are present in late summer and fall. 153

54 154 Arizona s Amphibians & Reptiles New Mexico Whiptail, Aspidoscelis neomexicana (Lowe and Zweifel, 1952) [Introduced] Adults grow to 82 mm, with a tail that is about 1.4x the length of the body. It is a whiptail with seven pale dorsal stripes with numerous spots between the stripes. The vertebral stripe has a wavy edge, a trait not found in any other Arizona whiptail. Distribution is in western Texas and New Mexico and probably present in adjacent Mexico. The isolate population found at the Petrified Forest National Park, Apache County, Arizona likely represents an introduced population. It uses disturbed habitats within the Rio Grande drainage including floodplains, grasslands with scattered shrubs, mesquite-creosote bush communities, river basins, washes, arroyos, and vacant lots. It is also present in ecotones, areas with debris left by humans. Only rarely does it occur in open areas within pinyonjuniper woodland. This lizard was not found in Arizona until Pai Striped Whiptail, Aspidoscelis pai (Wright and Lowe, 1933) Adults reach 85 mm SVL and have a tail about twice the body length. This sixstriped whiptail may have an incomplete seventh stripe. Dorsal spots are absent from the dark fields between the stripes. It is most easily confused with the Arizona Striped Whiptail (see above). The Pai Whiptail is an Arizona endemic, known only from the Grand Canyon and the Coconino Plateau eastward to the Navajo Reservation, with a disjunct population in the Mazatzal Mountains of Gila County. It is known from relatively few localities. This is a grassland-woodland species that avoids deserts.

55 Arizona s Amphibians & Reptiles Skinks The Skink family, Scincidae, is diverse, with more than 1,613 species. Like the anguids, they have osteoderms, a layer of bony armor lying just under their skin. They range in size from minute, with some species only 23 mm long, to the largest, which reach almost a half meter. They are present on all land masses, but usually avoid high latitudes and elevations. They may be terrestrial, arboreal, fossorial, or semi-aquatic. Skinks have adapted to niches in arid deserts, forests, and montane environments. They may be robust lizards with well-developed limbs or fragile, snake-like lizards with reduced or absent limbs. In the Australian deserts, skinks dominate the lizard fauna. However, in North American deserts they are almost absent. Arizona has only five species of skinks, and all are in the genus Plestiodon, a clade with a Eurasian, North American, and Middle American distribution. They are sometimes called blue-tailed skinks. Juveniles often have blue tails, but some species have adults that retain the juvenile coloration. Blue tails probably act as a predator-distraction mechanism. Females usually stay with the eggs after they have been laid. Ocellated Skink, Chalcides cf. ocellatus [Introduced] Thirty-one species of sand skinks of the genus Chalcides range across much of Eurasia and North Africa as far east as Pakistan. One or more of these skinks have been introduced at many different Arizona localities, most likely via the pet trade or relocation of ornamental plants. The Ocellated Skink, Chalcides cf. ocellatus, is now inhabiting about 30 ha of urbanized habitat in Mesa, Arizona. Its presence was noticed in 2001, but not confirmed until 2007 (Gunn et al. 2012). Chalcides have a generalized omnivorous diet. Adults may reach a maximum body length of 149 mm, with a tail that is slightly longer than the body. The dorsum is tan or light brown with black and white spots arranged in transverse bands arranged across the dorsum. The venter is a uniform white. Juveniles have a greenish tail. Females lay clutches of 2-20 eggs that hatch soon after deposition. 166

56 Reptilia - Skinks Mountain Skink, Plestiodon callicephalus (Bocourt, 1879) Other names for this skink include Eumeces callicephalus. Adults grow to 76 mm SVL, with the tail about twice the body length. Hatchlings are 20 to 25 mm SVL. A pair of yellow stripes joined at the snout extends to the back of the head, making this species readily recognizable. The dorsum ranges from a copper or bronze flecked with black to an olive-gray. A distinct dark brown lateral stripe extends from the snout to the insertion of the rear legs. Adult males have bright red lips. Like most North American skinks, juveniles have bright blue tails; this coloration is retained in the adult Mountain Skink. This is a Sky Island species that uses the upper elevation semi-desert grasslands and Madrean evergreen forest in the southernmost ranges of Pima and Cochise counties of Arizona and in southwestern New Mexico. It ranges southward in the Sierra Madre to Nayarit and Jalisco, Mexico. In elevation, it ranges from sea level to 2,000 m. The diet has not been well studied, but they will take a variety of small arthropods. Females have been reported to tend their clutches of three to six eggs, and if disturbed, will move the eggs by picking them up in their mouths. The tails are easily ejected by the lizard as a predator-escape mechanism. A long tail or a bright blue tail can act as a predator-distraction device, so that a predator s attention is drawn to the tail by color or movement. When the lizard loses its tail, it lives to grow another one. The tail-loss device and the bony armor of these lizards combine to make them better able to deal with predators. The female Mountain Skink seems adapted to its high elevation environment by retaining its eggs in its body until the embryos are well-developed. Zweifel (1962) reported a clutch of three eggs that hatched after nine days of incubation, and previous reports of incubation times had a minimum of 19 and 23 days. The nine- 167

57 168 Arizona s Amphibians & Reptiles day incubation period may have been possible because the eggs were maintained at 87 F. Egg retention allows the female to manipulate the temperature of the developing embryos to maximize their growth. There is additional evidence of extended post-hatching parental care. Cruz-Saén et al. (2011) observed the Mountain Skink in Jalisco, Mexico. Twice in the month of July they found female skinks under rocks with their eggs. In the first instance, the female had seven eggs and in the the second instance had three eggs. As the rocks were turned, the females began to transport the eggs away from the nest. Perhaps they were seeking a more secure and stable thermal environment. The skinks were at 1,230 m ASL in an oak forest. Many-Lined Skink, Plestiodon multivirgatus (Hallowell, 1857) Other names for this skink include Eumeces multivirgatus. Adult males can reach 68 mm in body length, while females are larger and reach at least 70 mm. The tail is 1.5 to two times the body length. The dorsum is covered with large, cycloid, scales that are shiny. There are two morphs, one with numerous dorsal and lateral stripes and one without the stripes. The striped morph has thin pale stripes separated by brown or olive-gray stripes. Ventral surfaces are a uniform cream or gray-tan. Hatchlings and juveniles are more vividly colored than adults and have a bright blue tail. Reproductive males have the labial scales turn orange or red. Stripes, if present, distinguish this lizard from all other Arizona skinks. If a patternless morph is in hand, it will also lack a divided mental scale. Both morphs may occur in the same population, and it has been suggested that the uniform morph is found more often in xeric habitats.

58 Reptilia - Skinks This lizard ranges from southern Colorado, southeastern Utah, Arizona, New Mexico, and western Texas at elevations of 910 to 2,620 m. In Arizona, it is on the Colorado Plateau in moist, rocky areas, and it has been reported to enter water. Note that the species Plestiodon multivirgatus is widely distributed from South Dakota to the Rocky Mountains southward to Mexico, with an elevation range of 900 to 2,500 m. But the northern population, Plestiodon m. multivirgatus is disjunct from the southern population, the subspecies that occurs in Arizona the Variable Skink, Plestiodon multivirgatus epipleurotus (Cope, 1880). The diet of this lizard has not been studied, but like other skinks, it will likely take a variety of small arthropods. Van Devender and Van Devender (1975) found this lizard in Chihuahua, Mexico, in a mesic habitat surrounded by arid grasslands. They observed females brooding small clutches (3 to 5 eggs) in early June and suggest it may produce two clutches per season. Great Plains Skink, Plestiodon obsoletus (Baird & Girard, 1852) Other names for this skink include Eumeces obsoletus. Adults grow to 142 mm SVL, with the tail 1.5 to two times the body length. Hatchlings are 36 to 41 mm SVL. A robust body, small legs, and a thick tail distinguish this skink from most other Arizona skink species. The dorsum is covered with smooth cycloid scales. It is tan to cream in color with the edge of each scale bordered with black, producing a net-like pattern on the body and limbs. It may have a pink or violet wash. Occasionally, the black is reduced and the dorsum appears to be flecked or spotted. Appendages may have a yellow or yellow-orange wash and the ventrolateral areas may have orange or salmon markings. Hatchlings are jet-black with a blue tail, with white or yellow spots on the lips, and a uniform gray venter. This species is unique among the Arizona skinks in having obliquely arranged scales on the dorsum. 169

59 Arizona s Amphibians & Reptiles The distribution includes northeastern Colorado, southern Nebraska, and southwestern Iowa through Arizona, New Mexico, Kansas, eastern Missouri, Oklahoma, Texas, and adjacent northern Mexico to northern Tamaulipas and Durango. Elevational range extends from near sea level to 2,650 m. A wide variety of mesic habitats are used. It prefers open habitats, but is known to use forested habitats as well. It uses ground cover and rodent burrows for refugia. While it likely evolved to inhabit prairies, it has been able to maintain populations in semi-desert environments where water is present. Eastern populations have been studied for diet composition. One study reported grasshoppers and caterpillars making up 99% of their prey. A second study found grasshoppers, spiders, and beetles composed much of the diet. While other Arizona skinks are diurnal, this species is reported to be partially nocturnal. Great Plains Skinks are active from late May to mid-september. Females produce a larger clutch of eggs than other Arizona skinks, and this is likely related to its larger size. Hatchlings, present in July and August, are black and grow rapidly in their first year, with growth slowing as they reach adult size (Bateman and Chung-MacCoubrey, 2011). Sexual maturity may not be reached until three years of age. Western Basin Skink, Plestiodon skiltonianus (Baird and Girard, 1852) Other names for this skink include the Western Skink, Eumeces skiltonianus. Adult reach 75 mm SVL, while hatchlings are about 25 mm in body length. Some populations of this skink are larger in body size than others. In Arizona the subspecies present is the Great Basin Skink, P. s. utahensis (Tanner, 1957). This is a small, slender skink with a small head and small legs. Its dorsum is covered with smooth cycloid scales. On the vertebral line is a wide, dark-brown stripe edged with black that extends from the snout to the tail. Two more lateral dark-brown stripes bordered by two pale stripes extend through the eyes to the tail, where they 170

60 Reptilia - Skinks continue onto the tail. The tail is gray to bright blue on young adults, and the blue fades with age. Juveniles are more vivid and have a higher contrast than do adults. In P. s. utahensis, the dorsolateral stripe occupies more than half of the second scale row and is almost one half the diameter of the dark dorsal interspace; the dark stripe below the lateral light stripe is rarely present. The width of the dorsolateral stripe is usually greater than the length of the first nuchal. While most individuals have a blue tail, there is one Arizona population with a red tail. Juveniles may have a red or blue tail. In Arizona, this lizard is known from two isolated populations, one in Mohave County and one in Coconino County, and it is found on the Kaibab Plateau and some of the higher peaks north of the Colorado River. Habitats range from montane meadows to pine-oak forests at 2,400 m ASL. These are fossorial lizards who dig burrows that may be several times their body length; they spend most of their time underground. Their diet includes a variety of arthropods, including lepidopterans, beetles, crickets, grasshoppers, and leafhoppers. Females become sexually mature in two years. They lay a clutch of 2 to 5 eggs in May or June, and the eggs hatch in July or August. Nest-guarding behavior has been reported in this species. Hatchlings are 24 to 26 mm SVL. Tails are readily autotomized when they encounter a predator. Wogan and Richmond (2015) showed that the thermal niches resulted in size divergence, and that these populations are reproductively isolated. They suggest that precipitation may have been as important as temperature in causing increased shifts in body size in this species in xeric habitats. Gilbert s Skink, Plestiodon gilberti (Van Denburgh, 1896) Other names for this skink include Eumeces gilberti. Adults grow to 114 mm SVL, with the tail about twice the body length. Hatchlings are 30 to 35 mm SVL. It is a large, robust skink covered with smooth cycloid scales. 171

61 Arizona s Amphibians & Reptiles The subspecies present in Arizona is the Western Red-tailed Skink, P. g. rubricaudatus (Taylor, 1935). The dorsum of adults is a uniform olive, tan, or brown with a dark edge on most scales; light and dark dorsolateral stripes may appear faded, and old adults may have considerable amounts of orange. Hatchlings have a blue tail that becomes red with age. Older juveniles have bright red limbs and tails, with a dark-brown mid-dorsal stripe bordered by pale cream or yellow stripes and a dark brown lateral stripe on the body. With age, the red fades as does most of the rest of the pattern. The Western Basin Skink has seven upper labials, whereas Gilbert s Skink has eight upper labials. The distribution extends from southern California along the western periphery of the San Joaquin Valley up to about the same latitude as the San Francisco Bay, and it is present in central Arizona. In Arizona, this skink uses a variety of habitats, ranging from deserts and grasslands to coniferous forests. It seems to associate with rocky streams and is not often found in the open, but undercover. The Western Redtailed Skink occurs in warmer and more arid environments relative to the smallbodied Great Basin Skink. In elevation, they range from sea level to 2,200 m. Females lay clutches of 3 to 9 eggs between June and August in a nest excavated by them, usually in loose, moist soil. Females probably attend the nest. Hatchlings have been found between May and August. Longevity is thought to be as long as six years. Its preferred body temperature is 31.5 C, but the optimal temperature for sprinting was higher, 34.1 C (Youssef et al., 2008). It has a complex systematic history and has been long confused with the Great Basin Skink. 172

62 Arizona s Amphibians & Reptiles The Gila Monster The family Helodermatidae contains the Gila Monster, Heloderma suspectum, a prominent, iconic, and ancient lizard. The four other species in the family are Mexican and Central American beaded lizards. Helodermatids have a robust body with well-developed limbs and a relatively short, thick tail. A suite of adaptations protects them against predators. These include a venomous bite, as well as osteoderms that form a layer of armor under the skin and are fused to the skull s surface. Helodermatids have long been considered the only venomous lizards and related to the monitor lizards of the family Varanidae. Therefore, it was not surprising when the monitor lizards were recently shown to also have venom and venom glands. The Gila Monster and beaded lizards shared an ancestor about 30 MYA, while two of the beaded lizards, H. exasperatum and H. horridum, last shared an ancestor about 4 MYA. Despite the ancient divergence of the Gila Monster from the beaded lizards, a recent study reported heloderm venom is quite conservative from one species to the next. Koludarov et al. (2014) found the venoms have a significant overall level of similarity in regard to protein/peptide types present but with variable expression within these conserved classes. The authors suggest that this variation pattern is likely a consequence of the fact that all helodermatid lizards intrinsically occupy the same ecological niche and feed on similar prey. The single best reference to Heloderma natural history and biology is Beck (2005). Gila Monster, Heloderma suspectum (Cope, 1869) Adults reach 360 mm SVL, with a weight of 700 g and may live for 20 years or more. This is perhaps the most easily recognizable lizard in the state, with its pink-and-black beaded scales, black snout, and short, but thick tail. It really cannot be confused with any other lizard. Two subspecies of the Gila Monster are sometimes recognized, and both occur in 182

63 Reptilia - The Gila Monster 183

64 184 Arizona s Amphibians & Reptiles Arizona. The Reticulate Gila Monster, Heloderma suspectum suspectum (Cope 1869), inhabits most of south-central and southeast Arizona, and the Banded Gila Monster, H. s. cinctum (Bogert and Martín del Campo, 1956), is in the southwest portion of the state. However, one molecular study found no support for differentiating two subspecies. Geographically, the Gila Monster is distributed in the Sonoran Desert of Arizona and Mexico, with populations extending into the eastern Mojave Desert and the western Chihuahuan Desert. The pattern differences between the two described subspecies appear to be ontogenetic. Young individuals are banded and their pattern becomes reticulated with age. Gila Monsters spend much of the year below ground. Activity above ground changes with the age of the lizard. Hatchlings are active from May through August. Sub-adults are active during a slightly broader time period that peaks in July, and adults are active in April and May. Activity can occur any time of the day or night. This lizard is carnivorous and a specialized nest predator that feeds on nestling birds and mammals, eggs of birds and reptiles, and carrion. Fat is stored in its tail. They may eat only four or five meals per year. It uses cloacal evaporative cooling to reduce its body temperature when it goes above 30 C, and it has the ability to use its urinary bladder as a water reservoir. Sexual maturity is reached in two or three years. Males engage in ritualized combat that look like wrestling matches for access to females. Mating takes place in spring and summer, and clutches of 2 to 12 eggs are laid in the summer. Hatchlings emerge from the nest the following spring. Females probably reproduce every other year. Bites and envenomation from this lizard were first reported in 1878 when an intoxicated Johnny Bostick placed his finger in the mouth of a Heloderma in Arizona s Tip-Top Mining Camp. The lizard s jaws had to be pried off the finger after the lizard was decapitated. Mr. Bostick immediately treated the envenomation and bite with more alcohol. Paralysis on one side of the body followed, and Bostick died three months later. It is unclear if his death was due to the venom or alcohol. Human deaths have since been linked to Gila Monster venom. A more recent account of a Heloderma bite was reported by Strimple et al. (1997). An adult male was bitten on the left hand by a 50 cm captive male Gila monster. Pain at the bite site that radiated into the arm and armpit, as well as swelling of the hand and forearm, began immediately. Systemic complaints of nausea, diaphoresis, and dizziness lasted approximately an hour. The patient suffered from persistent sensitivity to his skin, which eventually abated, and he made a full recovery. In 1999, an article published in the journal Diabetes by Harvard University s Gang Xu and colleagues reported that a molecule from the venom of the Gila Monster called exendin-4 stimulates the regeneration of the pancreas and the expansion of

65 Reptilia - The Gila Monster the b-cells in rats that had diabetes. This discovery suggested that the Gila Monster could hold the secret to a treatment for one of the most prevalent human diseases of the 21 st century. The extendin-4 molecule was approved January 27, 2012 under the trademark Bydureon, and it is now manufactured and sold by Amylin Pharmaceuticals and AstraZeneca for treating diabetes. Injury to Gila Monsters from the seeds of a non-native plant have been reported; a seed from the grass, Red Brome (Bromus madritensis), was found stuck in the eye of this lizard and resulted in inflammation. 185

66 Arizona s Amphibians & Reptiles Ancient Living Snakes About 155 MYA a snake lineage separated from all other snakes and became the ancestor of the modern Threadsnakes. Threadsnakes have degenerated eyes, thin cylindrical bodies, an upper jaw that lacks teeth, an absence of enlarged ventral scales, and a tail tip that terminates in a sharp spine (see below). These are so different from other snakes that it has been suggested that they are not actually true snakes. However, their DNA suggests otherwise. They live in burrows and crevices and are able to enter ant and termite nests without being injured from the attacks of the soldier castes. Once in the nest, they rapidly rake up the eggs and larvae of the insects, using an unusual motion of their jaws. However, they are not completely dependent on ants and termites and will feed on other soft-bodied arthropods. Punzo, (1974) commented on the diet of Arizona threadsnakes Stomach content analyses of 28 Leptotyphlops humilis humilis and 17 L. dulcis dulcis indicate that these snakes feed extensively on ants and termites, which comprise per cent of the total diet. L. d. dulcis appears to be more fossorial in its feeding activity than L. h. humilis, which preys on a greater percentage of surface-dwelling arthropods. Presumably, this serves to reduce competition for the available food supply in geographical areas of sympatry. Both species show a definite preference for soft-bodied prey-types. They are all egg layers, and some species are known to use communal nests, with females of some species attending the eggs. The eggs are very elongated and are usually fewer than eight per clutch. Today, two species of threadsnakes inhabit Arizona. The only other snake that could be mistaken for a threadsnake is the Brahminy Blindsnake, Indotyphlops braminus. This small snake has been introduced in the Phoenix area; it has 20 scale rows around the body (versus 14 rows in threadsnakes) and is darker in color than the threadsnakes. New Mexico Threadsnake, Rena dissecta (Cope, 1860) Adults grow to 300 mm total length. The tail is exceptionally short, so the total length is given instead of the SVL. The dorsum is pink to red-brown. The head is no wider than the body. The tail is blunt and has a downward-curved spine. Scales are in 14 rows, uniform in size around the body, and are glossy and hard. It has three scales between the supraoculars. This distinguishes it from the following species, which has only one scale at that position. The eyes are covered by a scale, and a small dark spot is visible under the ocular scale. 186

67 Reptilia - Ancient Living Snakes The New Mexico Threadsnake is a Chihuahuan Desert species using desertscrub to Madrean forest habitats from 900 to 2,100 m ASL. They require soil that they can burrow into and, in fact, may burrow quite deeply. One specimen was found 15 m below the surface. These snakes are well-known for eating ants and termites, but they will also take a variety of other soft-bodied insects. They have been reported to feed on fire ants. Little is known about their life history. One sexually mature female was found to be 193 mm in length. Most females are gravid in early summer and carry 2 to 7 eggs. The eggs are deposited underground. Remarkably, a paleontologist digging for fossils found females coiled around eggs 56 cm below the surface. The females were within 92 cm of each other. Old egg shells that had hatched in previous years were present. The Western Threadsnake, Rena humilis (Baird & Girard, 1853) Adults can reach 339 mm in total length. Hatchlings are about 90 mm in total length. The dorsal coloration is pink to red-brown to purple. The head is the same width as the body. The eyes are covered by an ocular scale and appear only as a small dark spot under the scale. The tail is blunt and has a downwardcurved spine. Scales are in 14 rows and are uniform in size around the body; they are glossy and hard. There is one scale between the supraoculars, which distinguishes it from the previous species, which has three scales in that position. The Western Threadsnake is widespread and known to use desertscrub to interior chaparral biomes. Four subspecies occur in Arizona. The Desert Threadsnake, Rena humilis cahuilae, occurs in southwestern Arizona, and it has 187

68 Arizona s Amphibians & Reptiles 12 scales around the base of the tail, 280 to 305 dorsals, and 16 to 21 subcaudals. The Southwestern Threadsnake, Rena humilis humilis, is found in northwestern and south-central Arizona and has 12 scales around the base of the tail, 257 to 283 dorsals, and 15 to 21 subcaudals. The Trans-Pecos Threadsnake, Rena humilis segregus, occurs in southeastern Arizona and has 10 rows of scales around the tail, 261 to 275 dorsals, and 12 to 16 subcaudals. The Utah Threadsnake, Rena humilis utahensis, occurs on the Arizona-Utah border in northwestern Arizona and has 12 rows of scales around the tail, 289 to 308 dorsals, and 17 to 20 subcaudals. Eastern screech owls collect Western Threadsnakes and bring them to their nest to feed on the soft-bodied insects that parasitize the nestling birds. But, on occasion the snakes are eaten. Gehlbach and Baldridge (1987) found nestling owls that lived with threadsnakes grew faster and had a lower mortality rate than broods that were not living with threadsnakes. In some habitats and under some conditions, these snakes are exceptionally abundant. Ant and termite presence, moist soil, and moonlight all seem to be involved in surface activity. Threadsnakes will follow the chemical trails laid down by ants or termites in order to locate their nests. Exactly how they avoid the bites of soldier ants and termites is not clear. Some have suggested that they raise the scale edges; others suggest that they produce a chemical that mimics the odor of the insects. 188

69 Reptilia - Colubrine Snakes Colubrine Snakes The superfamily Colubroidea is species-rich and contains the majority of the known species of snakes. It has more than 1,800 species, a worldwide distribution, and is the most successful group of advanced snakes. Arizona has about 27 species of colubroids in at least three of the families or subfamilies. Each of these clades colonized North America separately and at different times in deep history. While these snakes are often considered non-venomous, many have fangs on the back of the maxillary bone and venom glands. These snakes are often referred to as rear-fanged snakes. The fangs may be solid or have an open groove on the front surface of the tooth. In order to inject venom into their prey, they often make a chewing motion while holding the prey in their mouth. In the United States, most rear-fanged colubrid snakes are considered harmless to humans, but some bites may result in a mild reaction. The following species are members of the family Colubridae or subfamily Colubrinae, depending on whose taxonomy is used. The Neotropical Treesnake Clade One species of Arizona snake had its ancestor in a clade of South American treesnakes. The Brown Vine Snake seems out of place in North America; however, it reaches the most northern edge of its range here. It is related to the brightly colored, arboreal, parrot snakes of the genus Leptophis. Thornscrub Vine Snake, Oxybelis cf. aeneus This snake has also been called the Arizona Vine Snake, Oxybelis aeneus auratus; and the Brown Vine Snake. Adults reach 1,524 mm total length, and the tail is about 40 % of the total length. The elongated head and slender body make this the most distinctive colubrid snake in Arizona. It is brown to olive-brown or gray above and cream below with some yellow below the head and forebody. It has 17 scale rows, and Arizona specimens have 190 to 205 ventrals and 168 to 183 subcaudals. The Thornscrub Vine Snake has an exceptionally attenuated body, an elongated head, and eyes with an elliptical 195

70 pupil that has multiple openings. These traits will separate this snake from all other Arizona snakes. In Arizona, it is at the northernmost extent of its range, which extends southward through Central America and South America to Argentina. However, the Brown Vine Snake is a complex of cryptic species. The exact distribution of the species in Arizona needs to be determined. As currently understood, O. aeneus goes to Argentina. Arizona s Amphibians & Reptiles In extreme southern central Arizona, the Thornscrub Vine Snake inhabits temperate oak woodland, canyon riparian woodland, desertgrassland, and pine-oak woodland communities between 1,160 and 1,650 m elevation. It lives in areas with mild winter temperatures and relatively high annual precipitation that falls mainly as summer monsoon rain. It is diurnal and feeds on lizards (Holbrookia maculata, Sceloporus clarkii, and Typical defense behavior of the Thornscrub Vine Snake. Urosaurus ornatus). The exceptionally attenuated body allows it to bridge gaps between twigs to reach prey. 196

71 Reptilia - Colubrine Snakes Miniature Snakes that Eat Arthropods The snakes discussed here represent several different clades. They share a small size, a diet composed mostly of arthropods, and a fossorial or cryptozoic lifestyle. Eleven species fitting this description occur in Arizona. They have been placed in the Sonorini Clade by Holm (2008). However, he found the evidence for them to be related was ambiguous. Variable Sand Snake, Chilomeniscus stramineus (Cope, 1861) Also called the Banded Sand Snake, Chilomeniscus cinctus. Adults grow to 285 mm total length, and hatchlings are 100 to 110 mm; the tail is 9 to 15% of total length. The head is about the same width as the body, with the lower jaw countersunk, valvular nares, and internasals separated by a rostral. The dorsal pattern is composed of transverse black bands in between yellow, orange, or red rings; or it can be a uniform dorsum with each dorsal scale having a brown spot (Baja). The venter is cream to yellow with black bands encircling the body. A fossorial snake, it has small eyes, lacks a loreal scale, has a short tail, and a sharplypointed rostral. As its name suggests, the pattern can be quite variable and consists of transverse bands and spots. The small size, banded pattern, light-colored snout, and 13 scale rows at mid-body distinguish this snake from other Arizona snakes. It is distributed from south-central Arizona southward into Sonora and Baja. It inhabits deserts and semi-deserts with loose soil from sea level to about 900 m. It is considered a sand swimmer, spending most of its life below the surface. The Variable Sand Snake is nocturnal. It feeds on burrowing roaches and vermiform beetle larvae. 197

72 Arizona s Amphibians & Reptiles Feeding can occur under the soil. While this species has been thought to be several cryptic species in the past, currently only one species and no subspecies are recognized. Males become sexually mature at about 150 mm; females sexually mature at about 173 mm. Females lay two or three eggs. It is likely females do not reproduce every year. Kingsnakes prey on this species, and the sand snake will raise its body in defense, slamming it down in an attempt to deter the predator. Other predators include longnosed snakes, rattlesnakes, patch-nosed snakes, owls, and carnivorous mammals. The rostrum of the Variable Sand Snake is flattened, allowing the snake to push its way through loose soil. Desert Shovel-Nosed Snake, Chionactis annulata (Baird, 1859) This snake has also been called the Colorado Desert Shovel-nosed Snake, Chionactis occipitalis annulata. Adults grow to 430 mm total length, with a tail that is 17 to 20% of the total length. The 198

73 Reptilia - Colubrine Snakes The Tucson Shovel-Nosed Snake was a candidate for the endangered species list. But, in 2014 the U.S. Fish and Wildlife Service announced that threatened or endangered status was not warranted, and they removed the snake from their list of candidates. The current range of the Tucson Shovel-Nosed Snake includes Pinal, Maricopa, Yavapai, Yuma, Pima, and La Paz Counties in central and western Arizona. Apparently the last Tucson Shovelnosed Snake seen in Pima County was in the Avra Valley in 1979 (Rosen 2003). However, the subspecies can still be found in other locations. Although the specific habitat is poorly known, it occurs within the Sonoran Desertscrub biotic community. It is usually associated with soils that are soft, sandy loams, with sparse gravel and arthropod prey. Recent work on the genetics of this species suggests the distribution is larger than originally thought. Urban development was considered to be a threat to the subspecies. head is the same width as the body. It has a snout flattened and spade-like, a countersunk lower jaw, and valvular nostrils. It has a wide black hood or band on the crown with a concave anterior edge. The dorsum has smooth, shiny scales. It has a cream or yellow body with fewer than 21 narrow, transverse black bands that usually don t completely encircle the body and are separated by red cross bands that are often incomplete and indistinct. Another four or five black bands are on the tail. Fifteen dorsal scale rows at mid-body will separate it from the Variable Sand Snake. 199

74 Arizona s Amphibians & Reptiles Distribution extends from extreme southeastern California southward into Baja California and northern Sonora, Mexico, and east into southwestern Arizona. It has two subspecies. The Colorado Desert Shovel-Nosed Snake, C. a. annulata (blue markers), is found in extreme southeastern California, east of the desert slope of the peninsular range to the Colorado River. It ranges southward into Baja California and northern Sonora, Mexico, and eastward into southwestern Arizona. The second subspecies is the Tucson Shovel-Nosed Snake, C. a. klauberi (dark blue markers) that Wood et al. (2014) found in central and western Arizona including La Paz, Maricopa, Pima, Pinal, Yavapai, and Yuma counties. Elevational range is m. Intergrade populations are shown with red markers. Nocturnal, it is a sand-swimming species that spends most of its time below the surface. It may on occasion be found by day in shaded areas, but most often it is found crossing desert roads at night. Deserts with little vegetation, loose soils, and rocky areas seem to be preferred habitats. Active foraging is commonly used to locate food. The diet is composed mostly of arthropods, and it may prefer scorpions. Also consumed are centipedes, spiders, lepidopteran pupae, beetles and their larvae, and lizard eggs. Prey may be captured and swallowed while the snake is underground. Males mature at about 194 mm SVL, and most are mature at 250 to 260 mm TL. Copulation has been observed in the field in late May. Clutches of usually 2 to 6 eggs are laid from March to July. Incubation has been reported to be 94 to 99 days. Hatching probably occurs from June into September. Hatchlings are 112 to 124 mm TL. Male combat in captive males involved snakes intertwined and writhing under the sand for less than a minute. Biting, entwining, and tail vibration were also observed. Mojave Shovel-Nose Snake, Chionactis occipitalis (Stickel, 1941) Adults grow to 430 mm total length; the tail is 15 to 20 % of total length. The head is the same width as the body. It has a snout flattened and spade-like, a countersunk lower jaw, and valvular nostrils. The dorsum has smooth, shiny scales in 15 rows. It has a cream or yellow body with 21 or more, narrow, transverse brown bands that usually do not encircle the body and have no red saddles between them. The absence of saddle-like blotches between the black bands will distinguish this species from the other shovelnosed snakes. 200

75 It occurs in Mojave County, Arizona, but its distribution also includes southern Nevada and southeastern California. Its elevational range is below 600 m. Reptilia - Colubrine Snakes The burrowing activity of this snake was studied by Norris and Kavanau (1966) in a specially-built environmental chamber they called a fossorial activity chamber. They observed that Chionactis occipitalis often emerges at night in a more or less synchronous fashion over extensive areas of desert. Their experimental studies of this phenomenon suggested that the coordinated emergence is regulated by a circadian rhythm acting with near-surface sand temperatures. They also observed that the downward pressure of shallow, loose sand upon a buried snake is about the same as that of a fluid of equal density, but the lateral pressure is lower. Pressure exerted on the snake s dorsal surface was passed to the ventral surface. The maximum period of submergence beneath dry sand seems to be temperature-dependent, being shorter at high temperatures, while the basal metabolic rate seems to be somewhat depressed by the sand s weight. Submerged Shovel-Nosed Snakes moved air by rapid gular fluttering movements. During active burrowing, the downward-bent head and the overhanging rostral scale produce a sand-free cavity an air pocket used for inhaling and exhaling. Norris and Kavanau (1966) also observed that C. occipitals seized scorpions near the base of the stinger. In two instances, the snake backed into the sand, dragging the scorpion behind to orient the prey for swallowing. Even when it did not submerge with the prey, the snake initiated swallowing by moving the jaw opposite the side that held the stinger. The scorpion was inched down the throat of the snake and bent into a U-shape. The stinger was held firmly as the body of the scorpion disappeared into the snake s mouth. Finally, when all that remained to be swallowed were the stinger and the claws, both were swallowed simultaneously. They also observed that the Shovel-Nosed Snake sheds its skin while submerged, but comes to the surface to defecate. Males produce sperm in spring and early summer. Female reproductive activity takes place during this period. Females lay two or three eggs. 201

76 Arizona s Amphibians & Reptiles Gartersnakes & Water Snakes Natracines, often called water snakes, have a Holarctic distribution with about 29 genera and 210 species found across Asia, Europe, North Africa, sub-saharan West Africa, as well as North and Central America. Many of these snakes are associated with aquatic habitats and feed on fish and frogs, some have adapted to xeric conditions and may feed on invertebrates or mammals. Molecular studies suggest the natricines evolved from a colubroid ancestor in the Eocene or Oligocene. Gartersnakes of the genus Thamnophis are North American members of the Natracidae. Natrids occur in Eurasia, North America, Central America, and Africa. As a group, they seem more tolerant of low temperatures than other snakes. The Western Hemisphere clade Thamnophiini contains about 60 species from Canada to Costa Rica. They tend to feed on soft-bodied prey, but a few have adapted to feeding on crayfish. All of the North American members share an ancestor that originated in Asia and colonized North America, probably across the Bering Land Bridge sometime in the Miocene, MYA. Gartersnakes are viviparous and females give birth to live young which they have nourished with a combination of yolk and nutrients supplied from the female s blood stream through a placenta. Arizona has five species of gartersnakes. Four of Arizona s gartersnakes have three longitudinal yellow stripes and are easy to confuse, and some may occur together. By determining what lateral scale row has the yellow stripe on the anterior of the body it is possible to distinguish them. The Black-Necked Gartersnake has the yellow stripe on rows two and three; the Mexican Gartersnake has the lateral stripe on scale rows three and four, and the Checkered Gartersnake has the stripe restricted to row three. Gartersnakes and most other thamnophiines have females that are larger than males. The only non-gartersnake natricine present in Arizona is the recently introduced Banded Watersnake. Banded Watersnake, Nerodia fasciata (Linnaeus, 1766) [Introduced] Adults grow to 1067 mm. It is a heavy-bodied, semi-aquatic snake with a broad head and keeled scales. There is a dark postocular strip to the rictus. Dorsum is variable and can be light brown, red-brown, or almost black with darker transverse bands. The bands are longer on the vertebral line than laterally. The bands tend to fade with age. The venter is patterned with square blotches. Its native 246

77 Reptilia - Garter Snakes & Water Snakes distribution is the coastal plain between North Carolina and Alabama. They use freshwater habitats and feed on fish and amphibians. Females may have 20 offspring in a litter that are usually born in late summer. Its presence in California has been known for a number of years, but it was found in Yuma in October of It has been found northeast of Yuma, along the Colorado River at the border of California and Arizona at Laguna Dam, Senator s Wash, and at Mittry Lake in Arizona. Black-Necked Gartersnake, Thamnophis cyrtopsis (Kennicott 1860) Adults grow to 1,070 mm in total length, with the tail 22 to 27% of the total length. Neonates are 150 to 280 mm in total length. The head is wider than the forebody. The dorsum is a dark olive-gray with an orange-yellow vertebral stripe and a lateral cream or white stripe on scalerows 2 to 3. There are 19 rows of keeled scales at mid-body. Two lateral black blotches are present immediately behind the head, giving this snake its common name. Ventral surfaces are a uniform gray or cream. Black pigment is present on the upper labial seams. The stripe on rows 2-3, and the pair of black blotches distinguish this snake from other Arizona gartersnakes. The Mexican Gartersnake and the Checkered Gartersnake have 19 scale-rows, but the yellow stripe is on rows 3-4 and scale-row three respectively. The Terrestrial Gartersnake and the Narrow-Headed Gartersnake have 21 midbody scale-rows. The distribution ranges from Utah and Colorado southward to Guatemala. Three subspecies are recognized, but only the Western Black-Necked Gartersnake, T. c. cryptus, occurs in Arizona. While they tend to follow streams and stay close to water, these snakes will wander overland a kilometer or more from a water source in deserts or coniferous forests. Like other gartersnakes, they have venom glands and venom, but they are not considered dangerous to humans. The venom is used to help them subdue prey, 247

78 Arizona s Amphibians & Reptiles I (RCC) was hiking around Sabino Canyon and needing to escape the heat, I went to Sabino Dam to rest and see if there was any water left that might have critters in it. Movement caught my eye, and I noticed a small Black Necked Gartersnake swimming around in what amounted to a large, algae-filled, muddy muck hole. With camera at the ready, I photographed the snake for the better part of two hours. It would swim around, notice me, and hide. Sometimes it would peek its head out of the murk and survey to see if I was still there. Of all the images I took, I kept only one. It shows the innocent, shy nature of snakes, while being authentic, comical, sweet, and wild. If any image of a snake could change the mind of a snake-hater, I think this would be it. mostly frogs (particularly the Red-Spotted Toad and Chiricahua Leopard Frog), although neonates and juveniles will feed on worms and small fish. This snake can often be seen coiled in a stream behind rocks, waiting to ambush prey. In Arizona, it is active from March to October and has an average body temperature of 26 to 27 C. Its activity is primarily diurnal. Sexual maturity is reached in males at about 34 cm, and in females at about 41 cm. Courtship and mating occur in the spring, as well as in the fall. The young are born from June to August, and the average litter size is about 10, with a range of 3 to 24 young per litter. Terrestrial Gartersnake, Thamnophis elegans (Baird & Girard, 1853) Adults grow to 1,090 mm in total length, with the tail 18 to 28% of the total length. Neonates are 170 to 280 mm. The head is wider than the forebody, and keeled dorsal scales are in 21 rows at mid-body. The color and pattern in this snake are variable and may be related to the background the snake lives on. The dorsum is gray, brown, or green, often with pale dorsal and lateral stripes. The dorsal stripe is often yellow, brown, or orange, bordered with black that fades on the tail. Checkered markings are found 248

79 Reptilia - Garter Snakes & Water Snakes laterally between stripes. The ventral surface is pale with scattered black pigment towards the mid-ventral line, or the venter may also be black with a pale gular area and tail. These traits distinguish the Terrestrial Gartersnake from other Arizona gartersnakes. In Arizona, the subspecies is the Wandering Garter Snake, T. e. vagrans. The Wandering Gartersnake ranges from western Canada southward to New Mexico and Arizona and ranges in areas where it occurs with the Black-Necked Gartersnake and the Narrow-Headed Gartersnake. This species is often associated with vegetation close to the water s edge, while the other two species use more open, rocky habitats. The Wandering Gartersnake is more terrestrial and has a broader diet than the Black-Necked Gartersnake. It will eat worms, fish, and amphibians, as well as mammals. Additionally, its venom has been implicated in bites to humans with some severe symptoms. Although they have about the same mean body temperature as the Black- Necked Garter Snake, the body temperature of this species can vary dramatically in the course of a day (4 to 33 C), in part because it lives at elevations up to 3,200 m. Reports suggest that it may actually wander above this elevation: it has been found at 3,658 m on Humphrey s Peak in the San Francisco Peaks in Alpine Tundra, 150 m above the tree line. Stevenson et al. (1985) examined how body temperature affects physiological and behavioral processes in this species and found the maximum speed of crawling occurred at 34.5 C and swimming at 28.5 C. The digestion rate increased sharply above 20 C, to a maximum range of 25 to 35 C; all snakes regurgitated their meal at 10 C. The smallest reproductive female was 42 cm. It may take females two years to accumulate enough fat to reproduce. Litter size in Arizona populations ranges from 4 to 12, with the young being born between late July and mid-october. 249

80 Arizona s Amphibians & Reptiles Mexican Gartersnake, Thamnophis eques (Reuss, 1834) Adults grow to 1,120 mm in total length, with the tail 22 to 27% of the total length. Neonates are 225 to 258 mm total length. The head is wider than the forebody, and keeled dorsal scales are found in 19 rows at mid-body. Dorsal coloration is red-brown to olive-brown with a vertebral cream-colored stripe. There is a lateral stripe on scale-rows 3 to 4. Between the dorsal and lateral stripes are small dark dashes in two rows. The venter is pale yellow or cream. Black pigment outlines the seams of the labial scales. These traits distinguish the Mexican Gartersnake from other Arizona gartersnakes. In Arizona, the subspecies is the Brown Gartersnake, T. e. megalops (Kennicott, 1860). The Brown Gartersnake is distributed from southern Arizona and New Mexico southward across the Mexican Plateau and Highlands. In the past, it was found at low- to mid-elevations (530 to 1875 m) throughout the Gila River Basin and the headwaters of the Rio Yaqui in the San Bernardino National Wildlife Refuge. It was once common in the Tucson Basin. It has been extirpated from the area due to the alteration and destruction of its aquatic habitats and the introduction of bullfrogs. Surveys conducted during the 1980s and 2000 suggest that this trend is continuing. On 8 July, 2014, the Brown Gartersnake was listed as a threatened species under the U.S. Endangered Species Act. A population in Santa Cruz County, previously believed extirpated, was recently found to be surviving at low population densities. As many as 24 of the 29 known Brown Gartersnake localities in the United States (83%) are thought to be non-viable; if the snake is present it may exist only at low population 250

81 Reptilia - Garter Snakes & Water Snakes densities that could be threatened with extirpation or may already be extirpated. Bullfrogs, crayfish, and introduced game fish seem to be the culprits responsible for its decline. The introduced fish have eaten and out-competed their way through the native fish which was this species prey base. Plus, bullfrogs and crayfish are additional predators on this species. Only five populations in the United States are considered viable. In 2008, the total number of stream miles in the United States that historically supported the Brown Gartersnake were evaluated. Most of these miles are now permanently dry, except in the case of temporary flows from heavy precipitation. The conclusion was that the subspecies has been extirpated from, or occurs at low densities, in as much as 90 percent of its historical range in the United States. The Brown Garter Snake is highly aquatic and rarely moves far from permanent water with dense aquatic vegetation at elevations between 530 and 1,875 m. The diet includes invertebrates, fish, amphibians, reptiles, and mammals. It is also prey for large-mouth bass. These game fish are invasive in Arizona and are a serious threat to this vulnerable species. Females mature at about 530 mm total length and three years of age. Males probably mature at two years of age. Females likely reproduce every other year. Clutch sizes range from 4 to 38, with an average of about 14. The Brown Garter Snake is the sister to the Checkered Garter snake, Thamnophis marcianus. This species is listed as Threatened by the U.S. Fish and Wildlife Service, and it cannot be collected without special permits. Checkered Gartersnake, Thamnophis marcianus (Baird & Girard, 1853) Adults grow to 1,080 mm total length, with the tail 19 to 26% of the total length. Neonates are 123 to 279 mm total length. The head is wider than the forebody. The 251

82 Arizona s Amphibians & Reptiles A juvenile Marcy s Checkered Garter Snake. Snakes have become known for their ability to reproduce by facultative parthenogenesis (FP). This is the ability of a female to produce offspring asexually, as well as sexually. Reynolds et al. (2012) has shown that a female Marcy s Checkered Garter Snake, raised from a neonate in captivity produced five successive parthenogenetic litters produced over a seven year period that resulted in several viable male progeny. Two of the males achieved adulthood and showed the anatomical potential to reproduce. dorsum has 19 rows of keeled scales with apical pits. The dorsum has a yellow vertebral stripe, and lateral stripes on scale-row 3 are usually present (Some specimens may lack the lateral stripe.), tan, brown or yellow-brown. Rows of alternating black blotches are arranged in a checkered pattern laterally. A dark blotch is located immediately behind the head, with a light area between the dark blotch and the rictus. The ventral surface is a uniform pale cream or gray that may have some faded dark pigment. These traits distinguish the Checkered Gartersnake from other Arizona gartersnakes. The subspecies present in Arizona is Marcy s Checkered Gartersnake, T. m. marcianus. Its distribution ranges from Kansas southward to Veracruz, Mexico and westward to southern California and Baja. In Arizona, it is present in the southern third of the state. This is a lowland species that may reach altitudes of 1,700 m ASL. It is often associated with watercourses, roadside ditches, ponds, and irrigated agricultural land. It will travel overland to find water. It is associated with Sonoran and Chihuahuan desertscrub, semi-desert grassland, and plains grassland. Its diet is diverse: it preys upon worms, mollusks, crustaceans, fish, amphibians, and reptiles. 252

83 Reptilia - Garter Snakes & Water Snakes The ecology of Marcy s Checkered Gartersnake was studied at Roper Lake State Park in Graham County, Arizona (Seigel et al., 2000). The park is in a desert grassland and the researchers examined the population, using a man-made pond. The snakes were active from March to October and could be active at any time of day. Snakes were always near the water, and only four specimens were found at distances greater than 10 m away from the water. Mating occurred in late March, and females gave birth between late May and early June. Litter size averaged 15 young. Like other gartersnakes, males scrambled to mate with females and form mating balls. The smallest gravid or newly-spent female was 515 mm SVL, and the smallest male found in the mating ball was 478 mm. This gartersnake seems to be doing relatively well, compared to the Brown Gartersnake, probably because it is more terrestrial and therefore avoids bullfrogs. Narrow-Headed Gartersnake, Thamnophis rufipunctatus (Cope, 1875) Adults grow to 1,115 mm total length, with the tail 21 to 25% of the total length. Neonates are 196 to 252 mm total length. The head is barely wider than the forebody and very elongated. The eyes are dorsally positioned high on the head, and the pupils are round. The dorsum is gray, green, tan, or brown, with paired dark spots that decrease in size posteriorly. Anteriorly, the spots may fuse into transverse cross bands. On the sides are rows of smaller spots. The venter is pale cream to gray, and it may be uniform or marked with rows of spots. The dorsal scales lack apical pits, are keeled, and are in 21 rows at midbody. This is a medium-sized garter snake without well-formed longitudinal stripes, a trait that will immediately separate it from other Arizona Thamnophis. These traits distinguish the Narrow-Headed Gartersnake from other Arizona gartersnakes. 253

84 Arizona s Amphibians & Reptiles The Narrowheaded Gartersnake inhabits the mountains of central and eastern Arizona and west-central New Mexico in the Mogollon Rim area, and there are disjunct populations in Mexico s Sierra Madre Occidental as far south as central Durango. In Arizona, it occurs in permanent streams flowing through pinyon-juniper, pine-oak woodland, and ponderosa pine forest, with a rocky substrate and reduced aquatic vegetation. It is often associated with Arizona alder, velvet ash, willows, and canyon grape at elevations between 744 and 2,400 m (Rosen and Schwalbe 1988). It rarely leaves the water; however, recent reports suggest that it will use intermittent streams. The diet includes aquatic invertebrates, fish, frogs, toads, tadpoles, and larval salamanders. Females produce litters of 8 to 18 young born July and August. Evidence suggests that the Narrow-headed Garter Snake has declined over much of its range in Arizona. Surveys in the mid-1980s suggested that the population at one locality was 1000 snakes, but follow-up surveys in 1999 to 2000 estimated the snake population at the same site to be 129. In 2006, a survey found fewer than 10 snakes. The declines were attributable to human recreation in the area, loss of habitat, and direct killing of snakes by humans. Also, large predatory invasive fish likely depleted its food supply (small native fishes) with the help of introduced crayfish, and the invasive fish and crustaceans are predators on the gartersnakes. This species is listed as Threatened by the U.S. Fish and Wildlife Service, and it cannot be collected without special permits. 254

85 Reptilia - The Coral Snake Coral Snakes The molecular clock suggests the American coral snake lineage split from the Asian coral snakes about 25.2 MYA, with the ancestor dispersing from Asia to the Western Hemisphere. Today there are about 86 species in three genera of coral snakes in Asia and the Americas. Asian coral snakes (five species of Sinomicrurus) are the closest relatives of the two genera of Western Hemisphere coral snakes (Micruroides and Micrurus). There are fossils from the European Miocene that have been labeled as being coral snakes (Micrurus). If these are indeed coral snakes, there are three possible scenarios outlined by Kelly et al. (2009): (1) the American coral snakes once had an extensive distribution in Eurasia and the Americas, and isolation of snakes in these two areas was substantially more recent than hypothesized; (2) the same as the previous hypothesis, but with early isolation followed by prolonged stasis, preventing morphological divergence of European and American lineages; (3) European fossil Micrurus may represent an independent dispersal from the New World, either overland via Asia or across the Atlantic from the American east coast. A fourth possibility is that the fossils are not Micrurus and represent Asian coral snakes or unrelated elapid snakes that are morphologically convergent with Micrurus. The Sonoran Coral Snake, Micruroides euryxanthus is the only coral snake species in Arizona. It is important in the history of coral snakes because it is the sister to all the other New World coral snakes. Thus, it is the closest living lineage to the ancestral coral snake, the ancestor that colonized the Western Hemisphere. Three subspecies of the Sonoran Coral Snake are recognized, but only one, the Arizona Coral Snake, M. e. euryxanthus, enters Arizona. The others are restricted to Mexico s west coast. Sonoran Coral Snake, Micruroides euryxanthus (Kennicott, 1861) Adults grow to 660 mm total length, with the tail about 8% of the total length. Hatchlings are 190 to 203 mm in total length. The head is black and about the same width as the forebody. The dorsum has 11 to 13 transverse bands of red, white, and black. The red and white (yellow) bands are in contact; the bands encircle the body; and the bands on the tail are black and white. There are many harmless snakes that have brightly colored, banded patterns that mimic coral snakes to a greater or lesser degree. In the United States, most of the harmless mimics do not have the red and yellow bands in contact. ( Red and yellow kill a fellow. ) The exceptions to this are the shovel-nosed snakes of the genus Chionactus, which have a color sequence identical to the coral snake pattern. However, the shovel-nosed snakes have red bands on the tail. Despite the description of the color pattern given by Kennicott, the red bands 255

86 Arizona s Amphibians & Reptiles A recent study of coral snake venom and the ability of Coralmyn, the coral snake antivenom, to neutralize the effects exhibited by the venom of the eastern Harlequin Coral Snake, Micrurus fulvius, and several other species, including the Sonoran Coral Snake had mixed results. The antivenom was ineffective against the venoms of the Texas Coral Snake and the Sonoran Coral Snake, but useful for the treatment of the Harlequin Coral Snake. Luckily, the Sonoran Coral Snake is rarely responsible for envenoming humans. 256

87 Reptilia - The Coral Snake often have scales with some black pigment, and Arizona specimens have been found with the red completely replaced by black, giving them a two-toned coloration. Sonoran Coral Snakes are distributed from central Arizona and southwest New Mexico southward to Mazatlán and Sinaloa, Mexico. They occur from 320 to 1,770 m ASL in a variety of habitats, including grassland, agricultural lands, desert, brushland, thornscrub, thorn forest, tropical deciduous forest, and lower pine-oak woodland, as well as in some urban situations. In Arizona, the Sonoran Coral Snake often occurs in rocky bajadas and canyons with upland desertscrub and desert grassland. This species is perhaps most common in arroyos and river bottoms. Its fossorial habits and nocturnal activity result in infrequent encounters with humans. However, it may be locally common and is most often encountered during the monsoon season when humidity is high. Sonoran Coral Snakes, like other coral snakes, tend to feed on elongated prey, primarily other snakes. Threadsnakes (Rena) are often found in their digestive systems. Females lay clutches of up to six eggs in mid-summer, with the hatchlings appearing in September. Defensive behaviors include hiding its head under a coil and waving its tail in the air, as well as cloacal popping. The venom is neurotoxic and human envenomations have been reported, but its small size, short fangs, and non-aggressive nature make bites uncommon. Coral snakes are a minimal threat to humans and their pets. Despite their neurotoxic venom, Sonoran Coral Snakes have their share of predators, not the least of which are the kingsnakes (Lampropeltis), the whipsnakes (Coluber), and a wide range of carnivorous birds and mammals. One unusual predator on this snake is the Black Widow, Lactrodectus hesperus. Of course, humans are also predators. 257

88 Arizona s Amphibians & Reptiles Rattlesnakes Rattlesnakes attract attention around the world because of their unique tail ornament and venom. Harvard University herpetologist, Thomas Barbour (1922), proposed rattlesnake rattles as a way to repel the hordes of grazing ruminants In other words, Barbour viewed rattles as a way to avoid being trampled by large mammals. Before and since his paper, other hypotheses have suggested explanations for this novel structure. Co-evolutionary scenarios involving extinct fauna are at best highly speculative, but are useful for stimulating experiments and research. They are also of interest just for the fun factor. Walk into any restaurant in Arizona, and you are likely to hear somebody discussing rattlesnakes. A phylogenetic analysis of the pit vipers based on four mitochondrial genes found that rattlesnakes have a single ancestor and Sistrurus (the Massasauga and Pygmy Rattlesnakes) to be the sister to Crotalus (all other rattlesnakes). This implies that rattlesnakes may have not evolved in Mexico, but farther north. A phylogeny and historic biogeography of vipers based upon four mitochondrial genes provided dates for various divergence events. Using molecular dating in conjunction with dispersal (vicariance analysis), pit vipers were estimated to have colonized the Western Hemisphere about 22.1 MYA (26.9 to 17.9 MYA) during the late Oligocene or early Miocene. At this time, northeastern Asia and Alaska (Beringia) were connected and covered with mixed hardwood and deciduous forest. These forest habitats are used by some Asian and American pit vipers even today. Wüster et al. also retrieved a date of 9 MYA or earlier for the most recent common ancestor of Sistrurus and Crotalus, based upon a fossil vertebrate from Sistrurus; the ancestral rattlesnake was present about 12 MYA. Therefore, pit vipers may have had a window of about three million years to evolve rattles (between 12 and 9 MYA). The idea that rattlesnakes used the rattle as a lure was first described in writing by Nathaniel Shaler (1872), but was probably established in folklore well before this date. Shaler hypothesized that the rattle s sound mimicked cicadas and functioned as a lure to attract birds to the rattle. Of course, not all rattlesnakes eat birds, and there is really no evidence for rattles serving this function in adult snakes today. The caudal-luring hypothesis proposed by Schuett et al. suggested that the rattle originally evolved to increase the visual attractiveness of the lure. Using this scenario, the rattle, or perhaps just the button, was first used to bring prey within striking distance. Caudal luring has most likely evolved multiple times in various clades of squamates. Ali Rabatsky surveyed snakes that caudal lure and found that caudal luring has been reported in 21 species of vipers, and that 67 species of vipers have contrasting tail colors. 258

89 Reptilia - Rattlesnakes North American grasslands and open woodlands supported numerous medium and large browsers and grazers between 12 and 9 MYA. During this time, the ancestral rattlesnake was evolving, and after 9 MYA there may have been considerable selection for larger, louder rattles. Carnivore and ungulate diversity in western North America abruptly increased 17.5 to 17.0 MYA, then decreased about 11 MYA, which was then followed by a period of stability in ungulate diversity. One hypothesis suggested this resulted from climate change induced by tectonic movements in the Basin and Range, Mojave, Columbia Plateau, and Rio Grande Rift. Thus, rattles on rattlesnakes may have evolved to prevent the snake from being stepped on by large mammals or eaten by carnivorous mammals, or perhaps both. Here I follow the taxonomy in Schuett et al. (2016) for Arizona rattlesnakes. Arizona has at least 15 species of the 43 species of known rattlesnakes. These are among the most studied of North American snakes. Thus, the accounts here are longer than those for many other species discussed in this book. Hybridization is relatively common in rattlesnakes and presents challenges to identification. Feldner et al. (2016) note the presence of unusual-looking rattlesnakes in northwestern Arizona just south of the Grand Canyon. These animals have been dubbed hualapaiensis, and they are similar to Crotalus lutosus and C. abyssus, although they don t appear to be hybrids. They are an unresolved problem that keeps the Arizona herpetofauna interesting. Grand Canyon Rattlesnake, Crotalus abyssus (Klauber, 1930) Adults grow to 1,067 mm total length, with tails about 5.9 to 7.3% of the total length. Neonates are about 250 mm. This is also sometimes called the Pink Rattlesnake because its body can be a light 259

90 Arizona s Amphibians & Reptiles brown, to vermillion, to a salmon pink in coloration. The coloration changes with age. Young individuals have a highly contrasting pattern. This species has 38 to 48 dorsal blotches outlined in black. It usually has 25 scale-rows at mid-body; 23 or 27 are rare but may result from counting slightly more posteriorly or anteriorly than mid-body. The distribution of this snake has been restricted to the Grand Canyon by some authors, but it is more widespread, following the Colorado River into Utah (Douglas et al. 2002). Klauber originally described this snake as a subspecies of Crotalus confluentus, and it has also been considered a subspecies of C. viridis, and C. oreganus. On the bottom of the Grand Canyon, it lives alongside the Great Basin Rattlesnake, C. lutosus. The ecology and movements of C. abyssus were studied by Reed and Douglas (2002) at Walter Powell Canyon, including a four-kilometer stretch of Little Colorado River Canyon floor. The bottom of the Grand Canyon is warmer and drier than the rims. Daily temperatures can exceed 40 0 C in mid-summer and rarely drop below freezing in winter. Reed and Douglas followed nine snakes using radio-telemetry. Two-hundred and twenty snake-movements were recorded over 330 snake-days for an overall 0.67 movements per day. On average, snakes moved 45 m per movement and 26 m per day. Males moved longer distances than females, but movement frequency was not significantly different between sexes. Unlike some other populations of rattlesnakes, Grand Canyon rattlesnakes exhibited low directionality of movements. Activity range-size varied from more than 4 ha to less than 30 ha among individuals tracked. The corridor-like canyon bottom resulted in elongate activity ranges. Rodents present in the study site included white-footed mice, pack rats, and pocket mice. Remains of all these rodents were found in fecal samples and in museum specimens of C. abyssus, along with remains of spiny lizards and whiptails. Researchers observed a telemetered female being courted by a non-telemetered male in late July for three successive nights. The male accompanied the female for more than 92 hours and spent less than 12 hours in vigorous courtship prior to an 8-hour copulation, an exceptionally long courtship for a snake. Arizona Black Rattlesnake, Crotalus cerberus, (Coues, 1875) Adults grow to at least 1,219 mm, with one reported at 1,650 mm. Most specimens are in the mm range. Tails are 5.4 to 6.9 % of the total length. Neonates are about 255 mm. The dorsum is dark gray, olive, brown or black, with coloration darker during the day. Dorsal blotches number 25 to 46. Young individuals may be a light tan with light brown blotches. Most have 25 scale-rows at mid-body. This species has two scales separating the nasal scale from the upper labials. 260

91 Reptilia - Rattlesnakes In his original description of the Arizona Black Rattlesnake, Coues (1875) wrote, The great size to which it attains, the caliber of the body, and black color combine to render it peculiarly repulsive. An unusual degree of virulence is attributed by backwoodsmen to the Black Rattlesnake, but probably without foundation. Despite Coues uncomplimentary description, Arizona Black Rattlesnakes are of scientific interest and quite handsome snakes. Snakes are normally regarded as asocial but some rattlesnakes form aggregations and recognize and preferentially associate with kin. Rattlesnakes are long-lived, take a considerable time to maturity and are viviparous. These are traits predicted to occur in social species. While aggregations of rattlesnakes have been assumed to form around resources, usually hibernacula, there is evidence that they aggregate with their genetic relatives. Amarello and Smith (2012) found an aggregation of Arizona Black Rattlesnakes including some pregnant females, their offspring, and an occasional male, together during the summer active season and have found nonrandom patterns. They are choosy about whom they associate with. Females also attend to their young, staying with them after birth and potentially guarding them from predators. Arizona Black Rattlesnakes are widely distributed in montane regions of the state north of the Madrean Line. They occur in the Sky Islands north of this line and extend eastward into New Mexico. They are associated with upper elevation woodlands from 900 to 2,734 m. The diet includes a variety of vertebrates, and it may take prey that are greater in mass than is the snake. Known prey includes the Cactus Mouse, Harris Antelope Squirrel, the White-throated Woodrat, and the Ash-throated Flycatcher, quail, American Robin, and several lizards. Hunting is diurnal. This species is predicted to be hit hard by climate change, with most of the habitat below the Mogollon rim lost by Additionally, there is evidence that more than one lineage is currently hiding under the name Arizona Black Rattlesnake, adding some urgency to investigating this snake in greater detail (Davis et al. 2016). 261

92 Arizona s Amphibians & Reptiles Two Arizona Black Rattlesnakes sitting outside their den. 262

93 Reptilia - Rattlesnakes Midget Faded Rattlesnake, Crotalus concolor (Woodbury, 1929) Adults may reach 750 mm total length, with most individuals usually 500 to 600 mm. Neonates are 140 to 222 mm. This is a small, pale rattlesnake. Like most rattlesnakes, studies to date show that they are sexually dimorphic in size, with larger males. There are 32 to 47 mid-dorsal blotches on the body. Dorsal scale-rows at mid-body number 25. The Midget Faded Rattlesnake is associated with canyons in the Green and Colorado River basins of Utah, Wyoming, and Colorado. In Arizona, it seems to be restricted to the canyons of the Colorado River in Coconino County. Relatively few specimens of this snake have been found in Arizona. The species has been considered a subspecies of Crotalus viridis and C. oreganus at various times. The ecology and behavior of the Midget Faded Rattlesnake was studied in Wyoming by Parker and Anderson (2007). They telemetered 50 individuals between 2000 and The primary diet was composed of lizards (associated with rock outcrops), though they will also consume small mammals and birds. Hibernacula contain small aggregations of 21 snakes or fewer. After emergence from hibernation, they spent several weeks shedding, often in aggregations, before migration to hunting sites in early summer. Movements and activity ranges are some of the largest reported for rattlesnakes. Minimum area was ha for males, 63.9 ha for non-gravid females, and 4.8 ha for gravid females. Males traveled a mean distance per year of 2,122 m. Non-gravid females traveled a mean distance per year of 1,956 m, and gravid and postpartum females traveled a mean distance per year of 296 m. Movements were often a straight line to and from discrete summer activity ranges. Once the snakes had arrived, short, multidirectional movements were detected, but some made multi-directional movements throughout the active season. Mating occurs between 21 July and 12 August. Gravid 263

94 Arizona s Amphibians & Reptiles females gave birth during the third week of August. Mean clutch size was 4.17 (with a range of 2 to 7). The neonate sex ratio was skewed, favoring females 1:1.24, and the neonates were sexually dimorphic in size (males SVL=44.1 cm; females SVL=40.8 cm). Activity patterns for the Midget Faded Rattlesnake are unusual for rattlesnakes, in that they are often found moving in the very early morning (1:00 a.m. to 3:00 a.m.) at relatively cool temperatures. The toxicity and individual variability in Midget Faded Rattlesnake venom was studied by Glenn and Straight (1977). Using mice, they found Midget Faded Rattlesnake potency comparable to the venoms of the Tropical Rattlesnake and the Mojave Rattlesnake. Individuals show a wide variability both in lethality and protein pattern. The venom appears to be one of the most lethal crotalid venoms in the New World. However, Young et al. (1980) found the venom profiles between the Prairie Rattlesnake, the Grand Canyon Rattlesnake, the Great Basin Rattlesnake, and this species showed only small differences. Using mtdna, Pook et al. (2002) found it to be more closely related to the Pacific coast rattlesnakes than those of the Great Basin. Foote and MacMahon (1977) noted greater similarity in the venom profiles of the Midget Faded Rattlesnake and the Southern Pacific Rattlesnake (Crotalus oreganus helleri). Great Basin Rattlesnake, Crotalus lutosus (Klauber, 1930) Adults reach 1,210 mm total length, with tails that are 5.6 to 7.2% of the total length. Neonates average 256 mm. This heavy-bodied rattlesnake has a thin forebody and a large, triangular head. The ground color usually matches the environment: pale gray, tan, light yellow, buffcolored. The dorsum has 32 to 49 dark blotches with light centers, bar-shaped or oval, and about equal to the spaces between them. The venter is pale, sometimes weakly mottled. Two pale stripes, sometimes indistinct, extend diagonally across the sides of the head. Keeled scales are in 25 rows at mid-body. The dorsal blotches 264

95 Reptilia - Rattlesnakes that are narrower or only slightly larger than the spaces between them are the best diagnostic traits for this snake. The Grand Canyon Rattlesnake has faded blotches in adults and the Midget-Faded Rattlesnake has blotches that are faint or absent. This Great Basin Rattlesnake occurs from the Sierra Nevada in California, across the Great Basin to the Rocky Mountains in central Utah, and southward to the Grand Canyon. In Arizona, it occurs in Mojave and Coconino counties between 550 and 2,400 m ASL. Douglas et al. (2002) reported it from both rims and the bottom of the Grand Canyon, where it lives with the Grand Canyon Rattlesnake. They suggest that it occupies a variety of habitats, has a broad elevational range, and is efficient at dispersal and colonization, following riparian corridors and canyon bottoms. Most studies on this species have been outside of Arizona, but in Arizona this snake is at the southern limit of its range. The northern latitude and elevation where the Great Basin Rattlesnake lives limits its annual activity to about 120 or 150 days per year. Hibernacula are usually associated with deep crevices in bedrock that face south. It sometimes shares its den site with the Desert Striped Whipsnake. Prey is captured from ambush, with the snakes often hunting by facing out of a burrow where they wait for a squirrel or other rodent to pass by. However, they will also feed on lizards and birds. Female Great Basin Rattlesnakes have been found to take two years to produce eggs. They start storing fat in late spring/early summer and ovulate in the summer of the following year once they have stored enough calories and nutrients. This is different from most rattlesnakes, who begin egg production in summer/fall and ovulate in the following late spring. Male Great Basin Rattlesnakes have a similar reproductive cycle to other rattlesnake species with sperm production occurring in summer, with a summer mating season (Glaudus et al. 2009). This reproductive cycle can be viewed as an adaptation to the cold environment of the Great Basin Desert. The systematics of this snake have long been confused, and it was previously considered to be a subspecies of the Prairie Rattlesnake. Prairie Rattlesnake, Crotalus viridis (Rafinesque, 1818) Adults reach 1,620 mm in total length; most are 800 mm or less; tails are about 5.3 to 7.1% of the total length. Neonates are about 240 mm. The forebody is slender, and the head is broad and triangular. The dorsal coloration often matches the background the snake is living on; it can be olive-green, straw-yellow, gray-brown, pink, or orange-brown. A series of large, dark blotches, often with thin white edges, runs the length of the back. Two more lateral rows of small blotches are present on each side. A dark ocular stripe extends from the eye to the corner of the mouth and is bordered by pale pigment (the best diagnostic trait to separate it from the 265

96 266 Arizona s Amphibians & Reptiles Midget Faded, Grand Canyon, and Great Basin Rattlesnakes). A dark transverse bar is often between the eyes. The dorsal scales are keeled and in 23 to 27 rows at mid-body. The tail has indistinct tan and black rings. The original description of the Prairie Rattlesnake by Rafinesque in 1818 was remarkable in several ways. Rafinesque wrote a letter to the American Monthly Magazine and Critical Review. In that letter he wrote: N. Sp. Crotalinus viridis. (Green Rattlesnake.) Body slender, green with several rows of brown oblong spots above, belly white. A curious species, found also by Mr. Bradbury, in the Upper Missouri, it was 2 feet long, and had three rattles. That was it, with minimal detail, no type locality and no illustrations, he described a new species of rattlesnake in 39 words. The Prairie Rattlesnake is distributed through the Great Plains from Alberta and Saskatchewan southward to Sonora, Chihuahua, and Coahuila, Mexico. In Arizona, it occurs in the northeastern portion of the state in Apache, Navajo, and Coconino counties between 1,000 and 2,700 m ASL. Prairie Rattlesnakes are active March through November, and their daily activity cycle is temperature-dependent: during the hottest time of the year they are nocturnal but become crepuscular at cooler times of the year. Individuals may hibernate alone, or they may hibernate in a group. Graves and Duval (1985) experimentally showed that in communal dens, the body temperatures of the snakes dropped more slowly than the body temperature of a lone individual. Slower cooling rates may benefit the snakes by allowing them to maintain a higher temperature overnight or on cloudy days while they are digesting food or gestating

97 Reptilia - Rattlesnakes embryos. It can also allow them to respond more rapidly to predators. During hibernation, they may share the den with other snakes, including gophersnakes, milk snakes, whipsnakes, and the Terrestrial Garter Snake. Gravid females may form rookeries a short distance from the hibernacula while they incubate their eggs. Litter size is correlated with body size, and females have 5 to 14 offspring per clutch (Degenhardt et al. 1996). Females may produce young each year, but more likely they reproduce once every two or three years. Living at high elevations with short activity seasons requires a longer time to accumulate fat and nutrients to produce young. Rattlesnakes have been found to have a set of behaviors called strike-induced chemosensory searching (SICS) that allow the snake to locate prey after it has bitten and released the prey. This is an adaptation to prey that can retaliate and injure the snake. Vision, thermoreception, and nasal olfaction all work to help the snake locate the prey once the venom has taken effect, but the vomeronasal chemoreception system is the most important sensory system to the snake locating its prey. Much of the experimental work done on SICS was done using Prairie Rattlesnakes. O Connell et al. (1983) found the SICS occurs at night and during the day. Mice are released after the strike and the rattlesnake follows the chemical trail left by the envenomated mouse. Western Diamondback Rattlesnake, Crotalus atrox, (Baird and Girard, 1853) Adults grow to 2,260 mm total length; tails are 5.8 to 7.9% of the total length. Neonates are 210 to 360 mm. This is a long, heavy-bodied pit viper with a slender forebody and a large, triangular head. Dorsal scales are keeled and in 25 rows at mid-body. Usually, 3 to 7 small scales occur on top of the head between the supraocular scales. A light stripe extends from behind the eye diagonally to the corner of the mouth. The background color and pattern are variable and usually conform to the substrate the snake is living on: gray, brown, olive, tan, or yellowish. The dorsum has diamond-shaped blotches that 267

98 Arizona s Amphibians & Reptiles The Western Diamondback is the most commonly encountered rattlesnake in Arizona. They are capable of living right alongside humans in residential areas. Nowak et al (2002) conducted radiotelemetry research to evaluate the effects of translocating nuisance rattlesnakes. They found that most snakes moved greater distances and more frequently after translocation, resulting in an increased activity range. More than 50% of the rattlesnakes returned to locations from which they were displaced. However, the survival rate of translocated rattlesnakes was low. 268

99 Reptilia - Rattlesnakes are brown or black, with light edges. The tail is encircled with black and white rings about equal in width; these are just anterior to the rattle. The combination of small scales between the supraoculars, the post-ocular stripe that goes to the corner of the mouth, the white and black bands of about equal size on the tail, and dorsal scales that are flecked with dark pigment, combine to distinguish this rattlesnake from all others. However, hybrids with other species do occur, and identification of these is problematic. The Western Diamondback Rattlesnake is legendary throughout its distribution, where it often is the dominant species in the snake community. It ranges from Arkansas westward to southern California and southward into Mexico. In Mexico, it occurs from Baja, Chihuahua, and Sonora southward to Veracruz. Disjunct populations are present in southern Mexico. In Arizona, it occurs over most of the southern two-thirds of the state. In Arizona, urbanized semi-desert grasslands often have golf courses. In these areas, this is the most commonly encountered snake. It can be seen basking on sidewalks, crossing streets and lying along curbs at night waiting to ambush a rodent. During and after the monsoon, Western Diamondbacks are frequently encountered. Thus, it adapts well to some human activity. Humans have intentionally increased the supply of surface water and unintentionally increased the food supply for rodents. The availability of prey can increase the number of snakes. Within its distribution, it is the most medically important snake, responsible for more serious envenomations to humans and human commensals than any other species; but it is also of great ecological importance for its impact on rodent populations. Western Diamondbacks consume a variety of vertebrate prey, including the Regal Horned Lizard and pack rats. Juveniles consume small lizards and convert to eating larger prey as they grow. Scavenging carcasses for food is also relatively common. Male Western Diamondbacks engage in ritualistic combat for priority access to females during the mating seasons, and larger males tend to win the contests and maintain dominance. This combat behavior can be mistaken for mating by people unfamiliar with snakes. The two males engage in a dance-like behavior in which one male tries to top the other by raising its head higher off the ground than the other male. Male Western Diamondbacks search for mates and court females using stereotypic behavior. Courtship can require days to weeks before mating, and copulation can last 24 hours or more. Males usually do not mate multiple times with the same female in a single breeding season. Females have a biennial reproductive pattern, but annual reproduction is not uncommon. Clark et al. (2014) examined the mating system of the Western Diamondback and detected high levels of multiple paternity within litters, but found little concordance between paternity and observations of courtship and mating behavior. Larger males did not father significantly more offspring, but they found evidence for size-specific male-mating strategies, with larger males guarding females for longer periods in the mating seasons. 269

100 270 Arizona s Amphibians & Reptiles The Western Diamondback has a fossil record that extends back to the Middle Pliocene (about 3.7 to 3.2 MYA), based on fossils from Scurry County, Texas. Fossil remains of Western Diamondbacks are unknown west of the continental divide until the Late Pleistocene, when they appear in the fossil record of Arizona, California, and Nevada. All of the fossil sites west of the continental divide from which Western Diamondback fossils are known have been radiocarbon dated, and none are estimated to be older than 13,000 years (Holman, 2000). The fossil data suggest that the Western Diamondback has inhabited at least the eastern portions of the southwestern United States and adjacent areas of Mexico since the middle Pliocene. Castoe et al. (2007) obtained historical information from genetic sampling of Western Diamondbacks. Tectonic uplift of the continental divide in the late Pliocene acted to separate the Chihuahuan and Sonoran deserts, with the only connecting corridor being the Cochise Filter. The genetic data suggests the east-west split in the Western Diamondback occurred about 1.36 MYA. The division between eastern and western populations of Western Diamondbacks is thought to be the result of the expansion of non-desert habitat in the region of the Cochise Filter. This prevented gene flow between the eastern and western populations. Sidewinder, Crotalus cerastes (Hallowell, 1854) Adults grow to 840 mm, but most are smaller, 470 mm, with tails about 5.7 to 8.5% of the total length. Neonates are 160 to 200 mm total length. This is a short, stout, heavy-bodied pit viper with a thin forebody, a large triangular head, and a thick tail with a rattle. Coloration often matches the substrate on which the snake lives. It can be cream, tan, brown, pink, or gray-black. The body has 28 to 47 dark, transverse blotches and a dark stripe from the eye to the rictus or slightly beyond it. The supraocular scale over each eye is enlarged and raised up over the eye, giving the appearance of a horn over each eye. These scales can fold down over the eyes to protect them when the snake is buried or crawling in underground burrows. Dorsal scales are keeled and in 19 to 25 rows at mid-body. No other rattlesnakes have an upturned supraocular scale or horn. The Mojave Desert Sidewinder, C. c. cerastes (red markers), has 21 scale-rows at mid-body and a brown basal segment on the rattle. The Sonoran Sidewinder,

101 C. c. rcobombus (blue markers), has 21 scale-rows and a black basal segment on the rattle. The Colorado Desert Sidewinder, C. c. lateropenes (dark blue markers), has 23 scale-rows at mid-body and a black basal segment on the rattle. Reptilia - Rattlesnakes Overall, the distribution occurs from southern Nevada southward through California, Arizona, northern Baja, and Sonora. In Arizona, it occurs along the western border of the state and extends eastward in the Sonoran Desert about as far as the western city limits of Tucson. Sidewinders feed on mammals, but will also take lizards, other snakes, and birds. Clark et al. (2016) wrote the following about foraging Sidewinders: The general foraging behavior of free-ranging sidewinder rattlesnakes (C. cerastes) in our study was very similar to that of other rattlesnakes including other populations of C. cerastes... Sidewinders exhibit a general pattern of mobile ambushing that characterizes many pit vipers, with long periods of coiled sitting and waiting in ambush punctuated by relatively short searching movements between ambush sites. Sidewinders rely on a rapid envenomating strike to kill and immobilize prey that come within strike range, and often release struggling prey, which is then relocated via chemosensory searching. As with other rattlesnake species, sidewinder strikes are only successful about half the time, and missed strikes frequently are the result of evasive maneuvers by prey... Additionally, sidewinders feed both day and night, although they have a more pronounced summer diet cycle than do Crotalus ruber, Crotalus oreganus, or Crotalus horridus, most likely due to the temperature extremes of their environment... Our results show that juveniles in their first summer exhibit very similar movement, activity, and hunting behaviors as adults. Juveniles adopted the general pattern of mobile ambushing characteristic of adults of various Crotalus species and other pit vipers. Adults and juveniles exhibited similar ambush-site residence times, movement times, and distances between sites. They also exhibited similar rates of chemosensory probing while coiled and behaved similarly toward potential prey, with no age-based differences apparent in types of prey encountered, or strike success. These patterns complement laboratory studies that indicate juvenile and adult C. viridis exhibit broadly similar prey-striking and handling behavior... In contrast, some other rattlesnake juveniles may adopt different foraging tactics than adults, including the selection of arboreal ambush sites 271

102 Arizona s Amphibians & Reptiles Sidewinders feed primarily on lizards and less frequently on mammals. Rarely do they feed on birds and snakes. Sidewinders consume a greater proportion of lizards in early spring and autumn, and a greater percentage of mammals in late spring and summer. This dietary shift likely results from seasonal changes in the activity patterns. Individuals can be diurnally active in early spring and autumn, but are predominantly nocturnal during late spring and summer (Webber et al. 2016). 272

103 Reptilia - Rattlesnakes Caudal luring is used by many snakes, including the Sidewinder, to attract prey. Reiserer and Schuett (2008) conducted two experiments with neonatal Sidewinders and 12 species of lizards to investigate stimulus control and visual perception. In one experiment, caudal luring was elicited using lizards that were living in the same range as the Sidewinder or living in a different range than the Sidewinder. Caudal luring occurred at a significantly greater frequency when using lizards that lived within the range of the Sidewinder. Similarly, lizards living within the range of the Sidewinder were attracted to luring snakes significantly more than those that were not. Not all Sidewinders used caudal luring; the behavior varies geographically and thus may have a genetic basis. In a second experiment, a potential predator, a live toad, was introduced to snakes that had been stimulated to lure by means of a prey dummy. In all trials, the snakes shifted their behavior to species-typical defensive displays, which included rapid tail vibration and audible rattling in individuals with two or more rattle segments. While Sidewinders will ambush and lure prey, they will also scavenge like many snakes. One specimen was photographed feeding on a dead Yuman Fringetoed Lizard. Rock Rattlesnake, Crotalus lepidus (Kennicott, 1861) Adults reach 828 mm total length, but most are about 400 mm; tails are 5.4 to 10.4% of the total length. Neonates are 166 to189 total length. Males are larger than females. The dorsal pattern is sexually dimorphic and often matches the background on which the snake is living. The Banded Rock Rattlesnake exhibits sexual color dimorphism. The background color for males is green and for females is gray, with both sexes possessing 13 to 24 (usually 17) narrow, dark brown or black transverse bands on the body, and one to six bands on the tail (Jacobs and Altenbach, 1977). Dark flecks or spots may form incomplete bands that may be present between the primary bands. The 273

104 Arizona s Amphibians & Reptiles dorsal scales are keeled and usually in 23 mid-body rows. The color pattern is often thought to be camouflage when the snake is on lichen-covered rocks. Neonates have a yellow tail that fades with age. In Arizona, the subspecies present is the Banded Rock Rattlesnake, C. l. klauberi. The dorsal pattern and the absence of a post-ocular stripe will distinguish this species from other rattlesnakes. It has been suggested that the adult females match the rocks in sunny areas, where they can bask while pregnant, while the adult males tend to stay in cooler areas with greenish lichen-covered rocks. The young are more mottled and have a yellow tail tip in order to lure in small lizards as prey. Young are born during the monsoon at the same time as the emergence of small lizards. In Arizona, the diet consisted of 55.4% lizards, 28.3% centipedes, 13.8% mammals, 1.9% birds, and 0.6% snakes. Sceloporus comprised 92.4% of lizards. Extrapolation suggests that Sceloporus jarrovii represents 82.3% of lizard records. In Arizona, these attractive serpents are found between 1,495 and 2,500 m, but usually 1,675 to 2,135 m in Madrean Evergreen Woodland (Prival and Porter 2016). This elevation is below the range of the Twin-Spotted Rattlesnake, but it overlaps the elevational range of the Ridge-Nosed Rattlesnake. All three of these Sky Island rattlesnakes are highly sought after in the black-market pet trade, and are often sought by indiscriminate collectors. Poachers also destroy their sensitive rocky habitats. In Arizona, this snake is protected by AGFD regulations and may not be collected without special permits. In the United States, this subspecies also occurs in southwestern New Mexico and in the Franklin Mountains of extreme western Texas. The Arizona distribution includes the Canelo Hills and the Chiricahua, Dos Cabezas, Dragoon, Huachuca, Santa Rita, Patagonia, Peloncillos, and Whetstone mountains. Another subspecies, the Mottled Rock Rattlesnake (C. l. lepidus) occurs east of this area in Texas and New Mexico, to the Hill Country of central Texas. Most of the Rock Rattlesnake s range is in Mexico, where it occurs as far south as San Luis Potosí. There are other subspecies in Mexico. Most researchers believe the systematics of Rock Rattlesnakes have not been adequately worked out. This species is well-named, as it is nearly always found in association with rocks often large rock slides in the clearings between trees. They are extremely wary and will quickly flee when approached; however, they tend to retreat to the nearest space, often below the rock they were on. A patient observer can pick a good vantage point that isn t too close, wait about 10 minutes, and they will usually re-emerge. Envenomation from this species is rarely reported and rarely happens unless the animal is handled. Despite its small size, short fangs, and low venom yield, this is a dangerous snake that can cause extensive hemorrhaging, and some Arizona populations have neurotoxic compounds in their venom. 274

105 Reptilia - Rattlesnakes Western Black-Tailed Rattlesnake, Crotalus molossus (Baird & Girard, 1953) Adults reach 1,300 mm, but most are about 1,000 mm; tails are 4.6 to 8.6% of the total length. Neonates are 229 to 315 mm. The forebody is slender, and the head is broad and triangular. The snout is usually black or dark brown. The keeled, dorsal scales are in 25 to 29 rows at mid-body. The dorsum can be brown, gray, yellowbrown, or gold-yellow with a series (22 to 39) of large, black or brown, hexagonal dorsal blotches. The blotches have jagged edges, which result from each scale being one color. Centers of the blotches are pale. Posteriorly, the blotches narrow, and become transverse cross bands. The tail is black, sometimes with muted, dark, graybrown rings. In Arizona, especially in the southeast part of the state at higher elevations, Black-Tails have a honey-yellow wash, making them among the most beautiful serpents in the area. At lower elevations Black-Tails are a muted green-gray with drab blotches and the snout is not marked with dark pigment. In Arizona, Western Black-Tails are mountain dwellers, ranging in elevation from 350 to 2,895 m ASL in the Pinaleños. Thus, they cover a wide variety of habitats, from desert foothills to montane coniferous forests. In general, however, they are probably most abundant in oak and pine/oak woodlands. Distribution is mostly in the southern half of the state, from the Mogollon Rim southward, but they are not present in the western lowland deserts. They occur well into Mexico, where they are replaced by other subspecies. Black-Tails are often associated with rocks and riparian areas. Recent genetic evidence demonstrated that there was a western form (C. molossus) and an eastern form (C. ornatus). It is ironic that the species called ornatus is less ornate than molossus. Crotalus ornatus, found in New Mexico and Texas, tends to 275

106 Arizona s Amphibians & Reptiles Hardy and Green (1999) described the basking behavior of the Northern Black-Tailed Rattlesnake, Gravid females bask in the early morning, sometimes with only the posterior portion of the body exposed to the sun and the remainder in shelter, then withdraw out of sight for the remainder of the day and night. Births occur in late July or early August, after the first heavy monsoon rains. 276

107 A reminder that amphibians and reptiles are an important part of the food web. 293

108 Arizona s Amphibians & Reptiles Appendix 1. Some common measurements. 294

109 Appendix Appendix 2. Some common amphibian measurements and nomenclature. 295

110 Arizona s Amphibians & Reptiles References Amarello M, Smith JJ Social Snakes? The role of kin selection in rattlesnake aggregations. Sonoran Herpetologist 25(12):129. Anderson CD, Gibbs HL, Douglas ME, Holycross AT Conservation Genetics of the Desert Massasauga Rattlesnake (Sistrurus catenatus edwardsii). Copeia 2009(4): Anderson JD Egg laying and nesting in Sceloporus scalaris slevini. Herpetologica 18(3): Anderson KE, Blackburn DG, Dunlap KD Scanning electron microscopy of the placental interface in the viviparous lizard Sceloporus jarrovi (Squamata: Phrynosomatidae). Journal of morphology, 272(4), Anderson RA An analysis of foraging in the lizard Cnemidophorus tigrinus. Pp , In Wright and Vitt (eds.) Biology of Whiptail Lizards (Genus Cnemidophorus). Oklahoma Museum of Natural History. Anguiano MP, Diffendorfer JE Effects of fragmentation on the spatial ecology of the California Kingsnake (Lampropeltis californiae). Journal of Herpetology 49(3): Archie JW, Bezy RL, Enderson EF Yarrow s spiny lizard (Sceloporus jarrovii Cope 1875): Lowe s line revisited. Sonoran Herpetologist 19:50 3. Arizona Game and Fish Department Lampropeltis triangulum. Unpublished abstract compiled and edited by the Heritage Data Management System, Arizona Game and Fish Department, Phoenix, AZ. 4 pp. Averill-Murray RC, CM Klug Monitoring and ecology of Sonoran Desert tortoises in Arizona. Nongame and Endangered Wildlife Program Technical Report 161. Arizona Game and Fish Department, Phoenix. Badman JA, Neinaber L, DeNardo DF, Holycross AT Milksnakes (Lampropeltis triangulum) from Cochise County: notes on captive breeding and pattern. Sonoran Herpetologist 16(2):15. Baird SF Description of New Genera and Species of North American Lizards in the Museum of the Smithsonian Institution; Remarks on the Lower Cretaceous Beds of Kansas and Nebraska, Together with Descriptions of Some New Species of Carboniferous Fossils from the Valley of... Proceedings of the Academy of Natural Sciences of Philadelphia. 1858: Ballinger RE Reproduction of the Texas horned lizard, Phrynosoma cornutum. Herpetologica 60: Barker, DG, Ridgenose Rattlesnake. Pp In: Rattlesnakes of Arizona (ed. Schuett et al. Eco Publishing, Rodeo, NM. Barrows CW, Hoines J, Vamstad MS, Murphy-Mariscal M, Lalumiere K, Heintz J Using citizen scientists to assess climate change shifts in desert reptile communities. Biological Conservation 195:82-8. Bateman HL, Chung-MacCoubrey A Growth and activity of Sceloporus cowlesi (southwestern fence lizard). Herpetological Review 43(1): Bateman HL, Chung-MacCoubrey A. Plestiodon obsoletus (Great Plains skink): Life history. Herpetological Review 42: Beck, DD Biology of Gila Monsters and Beaded Lizards. University of California Press, Berkeley. Bernheim HA, Kluger MJ Fever and antipyresis in the lizard Dipsosaurus dorsalis. American Journal of Physiology 231: Berry KH, Morafka DJ, Murphy RW Defining the desert tortoise(s): our first priority for a coherent conservation strategy. Chelonian Conservation and Biology 4: Best TL, Pfaffenberger GS Age and sexual variation in the diet of collared lizards (Crotaphytus collaris). The Southwestern Naturalist. 9: Bezy RL, Cole CJ Amphibians and Reptiles of the Madrean Archipelago of Arizona and New Mexico. American Museum Novitiates Number 3810:1-24. Bezy RL, Enderson EF, Bonine KE. (2004). Tlaconete Pinto Pseudoeurycea bellii (Gray, 1850) Arizona s Lost Salamander. Sonoran Herpetologist, 17, Bezy RL Variation, distribution, and taxonomic status of the Arizona night lizard (Xantusia arizonae). Copeia 1967: Bezy RL Elegant Earless Lizard, Holbrookia elegans Bocourt, The Sonoran Herpetologist 23(12): Blaine RA Biogeography of the North American Southwest sand lizards. Ph.D. Dissertation. Washington University, Saint Louis, Missouri. 300

111 References Blair WF Mating call and stage of speciation in the Microhyla olivacea-m. carolinensis complex. Evolution, 1: Bogert CM Isolation mechanisms in toads of the Bufo debilis group in Arizona and western Mexico. American Museum Novitates 2100:1 37. Bogert, CM, Del Campo RM The Gila Monster and its allies. Bulletin of the American Museum of Natural History 109, Bouskila A Interactions between predation risk and competition: a field study of kangaroo rats and snakes. Ecology. 76(1): Bowke RW, Sullivan BK Natural history notes: Bufo punctatus x Bufo retiformis (Red-spotted toad, Sonoran green toad). Natural hybridization. Herpetological Review 22:54. Brattstrom BH The food of the nightlizards, genus Xantusia. Copeia. 1952(3): Brennan TC, Holycross AT A field guide to amphibians and reptiles in Arizona. Arizona Game and Fish Department. Brown DE, editor Biotic communities: southwestern United States and northwestern Mexico. University of Utah Press. Bryson RW, De Oca ANM, Jaeger JR. Riddle BR Elucidation of cryptic diversity in a widespread Nearctic treefrog reveals episodes of mitochondrial gene capture as frogs diversified across a dynamic landscape. Evolution, 64: Bryson RW, Jaeger JR, Lemos-Espinal JA, Lazcano D A multilocus perspective on the speciation history of a North American aridland toad (Anaxyrus punctatus). Molecular Phylogenetics and Evolution, 64: Bryson RW, Smith BT, De Oca ANM, García Vázquez UO, Riddle BR The role of mitochondrial introgression in illuminating the evolutionary history of Nearctic treefrogs. Zoological Journal of the Linnean Society, 172: Burbrink FT, Yao H, Ingrasci M, Bryson RW, Guiher TJ, Ruane S Speciation at the Mogollon Rim in the Arizona mountain kingsnake (Lampropeltis pyromelana). Molecular Phylogenetics and Evolution. 60(3): Campbell B Rana tarahumarae, a frog new to the United States. Copeia 1931:164. Carpenter CC, Gillingham JC, Murphy JB. The combat ritual of the rock rattlesnake (Crotalus lepidus). Copeia Dec 30: Castañeda G, Gadsden H, Contreras-Balderas AJ, GarcÍa-De la Peña C Variation in home range of the side-blotched lizard, Uta stejnegeri, in Coahuila, Mexico. The Southwestern Naturalist. 52(4): Castoe TA, Spencer CL, Parkinson CL Phylogeographic structure and historical demography of the western diamondback rattlesnake (Crotalus atrox): a perspective on North American desert biogeography. Molecular phylogenetics and evolution. 42(1): Chandler RB, Muths E, Sigafus BH, Schwalbe CR, Jarchow CJ, Hossack BR Spatial occupancy models for predicting metapopulation dynamics and viability following reintroduction. Journal of Applied Ecology, 52: Clark RW, Dorr SW, Whitford MD, Freymiller GA, Putman BJ Activity cycles and foraging behaviors of free-ranging sidewinder rattlesnakes (Crotalus cerastes): the ontogeny of hunting in a precocial vertebrate. Zoology. 119(3): Clark RW, Ramirez G Rosy boas (Lichanura trivirgata) use chemical cues to identify female mice (Mus musculus) with litters of dependent young. The Herpetological Journal. 21(3): Clark RW, Schuett GW, Repp RA, Amarello M, Smith CF, Herrmann H-W Mating Systems, Reproductive Success, and Sexual Selection in Secretive Species: A Case Study of the Western Diamond-Backed Rattlesnake, Crotalus atrox. PLoS ONE 9(3): e doi: /journal.pone Claunch N, Taylor E Gambelia wislizenii (Long-nosed Leopard Lizard) Saurocaudophagy. Herpetological Review 48: Cole CJ, Taylor HL, Neaves WB, Baumann DP, Newton A, Schnittker R, Baumann P The Second Known Tetraploid Species of Parthenogenetic Tetrapod (Reptilia: Squamata: Teiidae): Description, Reproduction, Comparisons with Ancestral Taxa, And Origins of Multiple Clones. Bulletin of the Museum of Comparative Zoology. 161(8): Conlon JM, Mechkarska M, Coquet L, Jouenne T, Leprince J, Vaudry H, Kolodziejek J, Nowotny N, King JD. Characterization of antimicrobial peptides in skin secretions from discrete populations of Lithobates chiricahuensis (Ranidae) from central and southern Arizona. Peptides Apr 30;32(4): Cooper JG New Californian animals. Proceedings of the California Academy of Sciences (ser. 1) 2:

112 A 310 Arizona s Amphibians & Reptiles Acris blanchardi 36 African Clawed Frog 62 Ambystoma mavortium 68 American Bullfrog 47 Anaxyrus cognatus 24 Anaxyrus debilis 25 Anaxyrus microscaphus 28 Anaxyrus punctatus 29 Anaxyrus retiformis 31 Anaxyrus woodhousii 32 Apalone spinifera 90 Arizona Black Rattlesnake 260 Arizona elegans 226 Arizona Mountain Kingsnake 239 Arizona Mud Turtle 83 Arizona Night Lizard 178 Arizona Ridge-Nosed Rattlesnake 286 Arizona Toad 28 Arizona Treefrog 39 Aspidoscelis exsanguis 149 Aspidoscelis flagellicauda 151 Aspidoscelis neomexicana 154 Aspidoscelis pai 154 Aspidoscelis priscillae 155 Aspidoscelis sonorae 156 Aspidoscelis stictogramma 157 Aspidoscelis tigris 158 Aspidoscelis uniparens 159 Aspidoscelis velox 161 Aspidoscelis xanthonota 162 B Baja California Treefrog 40 Banded Watersnake 246 Barking Frog 57 Bezy s Night Lizard 179 Big Bend Patch-Nosed Snake 216 Black-Necked Gartersnake 247 Index Blanchard s Cricket Frog 36 Boreal Chorus Frog 42 Brahminy Blindsnake 190 C California Kingsnake 231 Callisaurus draconoides 108 Canyon Treefrog 37 Chalcides cf. ocellatus 166 Checkered Gartersnake 251 Chelydra serpentina 74 Chihuahuan Black-Headed Snake 209 Chihuahuan Green Toad 25 Chihuahuan Hook-Nosed Snake 205 Chihuahuan Nightsnake 244 Chihuahuan Spotted Whiptail 149 Chilomeniscus stramineus 197 Chionactis annulata 198 Chionactis occipitalis 200 Chionactis palarostris 202 Chiricahua Leopard Frog 48 Chrysemys picta 75 Clark s Spiny Lizard 130 Coachwhip 214 Coleonyx variegatus 173 Coluber bilineatus 211 Coluber constrictor 212 Coluber taeniatus 213 Common Chuckwalla 96 Common Lesser Earless Lizard 113 Common Sagebrush Lizard 132 Common Side-Blotched Lizard 146 Common Snapping Turtle 74 Cophosaurus texanus 110 Couch s Spadefoot 16 Craugastor augusti 57 Crotalus abyssus 259 Crotalus atrox 267 Crotalus cerastes 270

113 Index Crotalus cerberus 260 Crotalus concolor 263 Crotalus lepidus 273 Crotalus lutosus 264 Crotalus molossus 275 Crotalus obscurus 288 Crotalus pricei 277 Crotalus pyrrhus 279 Crotalus scutulatus 281 Crotalus tigris 284 Crotalus viridis 265 Crotalus willardi 286 Crotaphytus bicinctores 100 Crotaphytus collaris 101 Crotaphytus nebrius 103 Ctenosaura conspicuosa 92 Ctenosaura macrolopha 92 D Desert Grassland Whiptail 159 Desert Horned Lizard 125 Desert Iguana 93 Desert Kingsnake 234 Desert Nightsnake 243 Desert Shovel-Nosed Snake 198 Desert Spiny Lizard 135 Diadophis punctatus 240 Dipsosaurus dorsalis 93 Dryophytes arenicolor 37 Dryophytes wrightorum 39 E Eastern Collared Lizard 101 Eastern Patch-nosed Snake 216 Eastern Side-blotched Lizard 147 Elegant Earless Lizard 112 Elgaria kingii 164 F G Gambelia wislizenii 104 Gastrophryne mazatlanensis 60 Giant Spotted Whiptail 157 Gila Monster 182 Gila Spotted Whiptail 151 Gilbert s Skink 171 Glossy Snake 226 Goode s Horned Lizard 121 Gophersnake 227 Gopherus agassizii 86 Gopherus morafkai 88 Grand Canyon Rattlesnake 259 Great Basin Collared Lizard 100 Great Basin Rattlesnake 264 Great Basin Spadefoot 20 Greater Earless Lizard 110 Greater Short-Horned Lizard 122 Great Plains Skink 169 Great Plains Toad 24 Green Rat Snake 222 Gyalopion canum 205 Gyalopion quadrangulare 206 H Heloderma suspectum 182 Hemidactylus turcicus 177 Heterodon kennerlyi 241 Holbrookia elegans 112 Holbrookia maculata 113 Hyliola hypochondriaca 40 Hypsiglena chlorophaea 243 Hypsiglena jani 244 I Incilius alvarius 33 Indotyphlops braminus 190 Flat-Tailed Horned Lizard

114 K 312 Arizona s Amphibians & Reptiles Kinosternon flavescens 80 Kinosternon sonoriense 81 Kinosternon stejnegeri 83 Knobloch s Mountain Kingsnake 237 L Lampropeltis californiae 231 Lampropeltis gentilis 233 Lampropeltis knoblochi 237 Lampropeltis nigrita 232 Lampropeltis pyromelana 239 Lampropeltis splendida 234 Lichanura orcutti 191 Lichanura trivirgata 193 Lithobates berlandieri 46 Lithobates blairi 46 Lithobates catesbeianus 47 Lithobates chiricahuensis 48 Lithobates onca 51 Lithobates pipiens 52 Lithobates tarahumarae 53 Lithobates yavapaiensis 55 Long-Nosed Leopard Lizard 104 Long-Nosed Snake 225 Long-Tailed Brush Lizard 142 Lowland Burrowing Treefrog 43 Lowland Leopard Frog 55 M Madrean Alligator Lizard 164 Many-Lined Skink 168 Masticophis flagellum 214 Mediterranean Gecko 177 Mexican Gartersnake 250 Mexican Hog-Nosed Snake 241 Mexican Spadefoot 21 Micruroides euryxanthus 255 Midget Faded Rattlesnake 263 Mohawk Dunes Fringe-Toed Lizard 117 Mojave Desert Tortoise 86 Mojave Fringe-Toed Lizard 115 Mojave Rattlesnake 281 Mojave Shovel-Nose Snake 200 Mountain Skink 167 N Narrow-Headed Gartersnake 253 Nerodia fasciata 246 New Mexico Ridge-Nosed Rattlesnake 288 New Mexico Threadsnake 186 New Mexico Whiptail 154 Northern Leopard Frog 52 Northern Three-Lined Boa 191 O Ocellated Skink 166 Organ Pipe Shovel-Nosed Snake 202 Ornate Box Turtle 76 Ornate Tree Lizard 143 Oxybelis cf. aeneus 195 P Painted Turtle 75 Pai Striped Whiptail 154 Phrynosoma cornutum 119 Phrynosoma goodei 121 Phrynosoma hernandesi 122 Phrynosoma mcallii 123 Phrynosoma modestum 124 Phrynosoma platyrhinos 125 Phrynosoma solare 127 Phyllorhynchus browni 220 Phyllorhynchus decurtatus 221 Pituophis catenifer 227 Plains Black-Headed Snake 208 Plains Leopard Frog 46 Plains Spadefoot 18 Plateau Lizard 138

115 Index Plateau Striped Whiptail 161 Plestiodon callicephalus 167 Plestiodon gilberti 171 Plestiodon multivirgatus 168 Plestiodon obsoletus 169 Plestiodon skiltonianus 170 Pond Slider 79 Prairie Rattlesnake 265 Priscilla s Whiptail Lizard 155 Pseudacris cf. maculata 42 R Red-Backed Whiptail 162 Red-Spotted Toad 29 Regal Horned Lizard 127 Relict Leopard Frog 51 Rena dissecta 186 Rena humilis 187 Rena segrega 189 Rhinocheilus lecontei 225 Ring-Necked Snake 240 Rio Grande Leopard Frog 46 Rock Rattlesnake 273 Rosy Boa 193 Round-Tailed Horned Lizard 124 S Saddled Leaf-Nosed Snake 220 Salvadora deserticola 216 Salvadora grahamiae 216 Salvadora hexalepis 217 Sauromalus ater 96 Scaphiopus couchii 16 Sceloporus bimaculosus 129 Sceloporus clarkii 130 Sceloporus cowlesi 131 Sceloporus graciosus 132 Sceloporus jarrovii 134 Sceloporus magister 135 Sceloporus slevini 137 Sceloporus tristichus 138 Sceloporus uniformis 139 Sceloporus virgatus 140 Senticolis triaspis 222 Sidewinder 270 Sinaloan Narrow-Mouthed Toad 60 Sistrurus tergeminus 289 Slevin s Bunchgrass Lizard 137 Smilisca fodiens 43 Smith s Black-Headed Snake 207 Sonoran Collared Lizard 103 Sonoran Coral Snake 255 Sonoran Desert Toad 33 Sonoran Desert Tortoise 88 Sonoran Green Toad 31 Sonoran Lyresnake 219 Sonoran Mud Turtle 81 Sonoran Spotted Whiptail 156 Sonoran Whipsnake 211 Sonora semiannulata 203 Southwestern Fence Lizard 131 Southwestern Speckled Rattlesnake 279 Spea bombifrons 18 Spea intermontana 20 Spea multiplicata 21 Spiny Softshell 90 Spiny-tailed Iguanas 92 Spotted Leaf-Nosed Snake 221 Striped Plateau Lizard 140 Striped Whipsnake 213 T Tantilla hobartsmithi 207 Tantilla nigriceps 208 Tantilla wilcoxi 209 Tantilla yaquia 210 Tarahumara Frog 53 Terrapene ornata 76 Terrestrial Gartersnake 248 Texas Horned Lizard 119 Thamnophis cyrtopsis 247 Thamnophis elegans 248 Thamnophis eques

116 Arizona s Amphibians & Reptiles Thamnophis marcianus 251 Thamnophis rufipunctatus 253 The Western Milksnake 233 The Western Threadsnake 187 Thornscrub Hook-Nosed Snake 206 Thornscrub Vine Snake 195 Tiger Rattlesnake 284 Tiger Whiptail 158 Trachemys scripta 79 Trans-Pecos Threadsnake 189 Trimorphodon lambda 219 Twin-spotted Rattlesnake 277 Twin-Spotted Spiny Lizard 129 U Uma rufopunctata 114 Uma scoparia 115 Uma sp. 117 Urosaurus graciosus 142 Urosaurus ornatus 143 Uta stansburiana 146 Uta stejnegeri 147 X Xantusia arizonae 178 Xantusia bezyi 179 Xantusia vigilis 180 Xenopus laevis 62 Y Yaqui Black-Headed Snake 210 Yarrow s Spiny Lizard 134 Yellow-Backed Spiny Lizard 139 Yellow Mud Turtle 80 Yucca Night Lizard 180 Yuman Desert Fringe-Toed Lizard 114 Z Zebra-Tailed Lizard 108 V Variable Sand Snake 197 W Western Banded Gecko 173 Western Basin Skink 170 Western Black Kingsnake 232 Western Black-Tailed Rattlesnake 275 Western Diamondback Rattlesnake 267 Western Ground Snake 203 Western Massasauga 289 Western Patch-Nosed Snake 217 Western Tiger Salamander 68 Western Yellow-Bellied Racer 212 Woodhouse s Toad

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118 Author Arizona s & Photographer Amphibians Information & Reptiles John C. Murphy is a retired science educator with a lifelong interest in herpetology. His other books include: Tales of Giant Snakes; Amphibians and Reptiles of Trinidad and Tobago; Homalopsid Snakes: Evolution in the Mud; Secrets of the Snake Charmer: Snakes in the 21 st Century; Dogs and Snakes: avoiding the bite; and A Field Guide to the Amphibians & Reptiles of Trinidad & Tobago. Lawrence L. C. Jones is a retired biologist living in Tucson, Arizona, although he hails from Southern California and also worked in the Pacific Northwest. Among his other books are Lizards of the American Southwest and Amphibians and Reptiles of the Pacific Northwest. His current research includes a longterm monitoring project of lizards in southeastern Arizona. Mr. Jones is writing a new book, Venomous Animals of the American Southwest. Nationally-published nature photographer René C. Clark of Dancing Snake Nature Photography, specializes in capturing the beauty of Southern Arizona s wild inhabitants. In addition to supplying stock photography for various books and scientific publications, René conducts workshops and lectures on Reptile Photography and Wildlife Photography in the field. Gary Nafis is a former sound engineer and internationally-published wildlife photographer who has spent many years recording and photographing reptiles and amphibians for his online field guide to California s reptiles and amphibians, Californiaherps.com. 316

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