Tennessee Naturalist Program

Transcription

1 Tennessee Naturalist Program Tennessee Reptiles and Amphibians Scutes, Scales, and Skin Enhanced Study Guide 7/2018

2 Tennessee Naturalist Program Inspiring the desire to learn and share Tennessee s nature These study guides are designed to reflect and reinforce the Tennessee Naturalist Program s course curriculum outline, developed and approved by the TNP Board of Directors, for use by TNP instructors to plan and organize classroom discussion and fieldwork components and by students as a meaningful resource to review and enhance class instruction. This guide was compiled specifically for the Tennessee Naturalist Program and reviewed by experts in these disciplines. It may contain copyrighted work from other authors and publishers, used here by permission. No part of this document may be reproduced or shared without consent of the Tennessee Naturalist Program and appropriate copyright holders. 2

3 Tennessee Reptiles and Amphibians Scutes, Scales, and Skin Objectives Present an overview of reptiles and amphibians including characteristics particular to these two classes of animals. Explore their behavior, physiology, and ecology, relating these to habitat needs, environmental adaptations, and ecosystem roles, including human interactions. Introduce common species, their distinguishing characteristics and distribution. Time Minimum 4 hours 2 in class, 2 in field Suggested Materials ( * recommended but not required; ** TNP flash drive) Reptiles and Amphibians Eastern/Central North America, Third Edition Expanded (Peterson Field Guides), Roger Conant and Joseph T. Collins * Vocalizations of Tennessee Frogs and Toads, CD, TAMP (available free upon request) Tennessee s Reptiles and Amphibians Enhanced Study Guide, TNP ** Expected Outcomes Students will gain a basic understanding of 1. general characteristics of and differences between reptiles and amphibians 2. life cycle 3. breeding, juvenile, and adult habits and habitats 4. evolutionary development and ecosystem roles 5. amphibians as bioindicators 6. frogs and toads of Tennessee 7. salamanders of Tennessee 8. lizards, turtles, and snakes of Tennessee 9. rare species; threats and conservation issues 3

4 Reptiles and Amphibians Curriculum Outline I. Reptile and Amphibian Characteristics A. Egg differences B. Skin differences C. Claws D. Ectothermic II. Amphibian life cycle and associated habitats A. Egg masses B. Larvae and juvenile stages C. Adults, hibernation and migration D. Communication and breeding 1. amplexus in frogs and toads 2. salamander fertilization E. Evolutionary development of salamanders F. Amphibian ecological roles 1. bioindicators III. Amphibians of Tennessee - Class Amphibia: General Characteristics and Identification A. Order Anura (no tail) - Frogs and Toads (voice ID) 1. Family Bufonidae - true toads 2. Family Pelobatidae - spadefoot toads 3. Family Hylidae - treefrogs 4. Family Microhylidae - narrowmouth toads 5. Family Ranidae - true frogs B. Order Caudata (tail) - Salamanders 1. Family Ambystomatidae - cup mouths 2. Family Salamandridae - newts 3. Family Plethodontidae - lungless 4. Families Cryptobranchidae, Proteidae, Amphiumidae, Sirenidae - giants IV. Reptile Life Cycle and Associated Habitats A. Eggs and live birth B. Adults, breeding, shedding, hibernation (hibernacula) C. Ecological roles 4

5 V. Reptiles of Tennessee - Class Reptilia: General Characteristics and Identification A. Order Testudines - Turtles 1. Family Chelydridae - snapping turtles 2. Family Kinosternidae - musk and mud turtles 3. Family Emydidae - box and water turtles 4. Family Trionychidae - softshell turtles B. Order Squamata, Suborder Lacertilia - Lizards 1. Family Polychridae - anoles 2. Family Scincidae - skinks 3. Family Phrynosomatidea, Genus Sceloporus - spiny lizards 4. Family Teiidae - whiptails 5. Family Anguidae - glass lizards C. Order Squamata, Suborder Serpentes - Snakes 1. Family Colubridae - colubrids, typical snakes (non-venomous) 2. Family Viperidae, Subfamily Crotalinae - pit vipers (venomous) VI. Conservation Issues A. Habitat loss B. Commercial exploitation C. Pollution D. Disease 1. Chytrid fungus 2. Rana virus E. Human misperception VII. Resources A. Publications B. Organizations C. Internet VIII. Review Questions 5

6 Tennessee Reptiles and Amphibians Tennessee has a rich herpetofauna. Herpetofauna are the amphibians and reptiles that occur in an area. The word herpetofauna comes from the Greek word herpeton meaning creeping animal. Tennessee s amphibians are the frogs, toads and salamanders. Other amphibians include caecilians but they are found only in the tropics. Our state s reptiles are the lizards, turtles and snakes. Other reptiles include alligators, crocodiles and tuataras. A Checklist of Tennessee Amphibians and Reptiles is in Appendix A. Here is a list of the numbers of species of herps that occur in our state. Frogs and Toads 21 Salamanders 54 Lizards 9 Turtles 15 Snakes 32 I. Reptile and Amphibian Characteristics Differences between amphibians and reptiles are as follows. Amphibians Have moist skin without scales Eggs are gelatinous No claws on toes Reptiles Dry skin covered in scales Eggs have a leathery shell When feet are present, toes have claws Both amphibians and reptiles are ectothermic (cold-blooded) meaning that their body temperature is determined by the temperature of their environment. They are also both vertebrates. II and III. Amphibians -- Order Anura, Frogs and Toads A frog is an amphibian, an animal that lives part of its life in water and part of its life on land. Frogs and toads are members of a group of animals called anurans. In Latin this means a (no) and nuran (tail). Thus, they belong to an order which means "no tail." Another name for their order is Salientia which means to leap. 6

7 Eggs and Tadpoles Amphibians are born in the water and hatch from gelatinous eggs into tadpoles or pollywogs. The eggs of amphibians are considered by scientists to be an evolutionary precursor to the land adequate reptilian egg. However, the amphibian egg is a marvel in itself. Once laid and fertilized, the amphibian egg takes in water and enlarges. The outer envelope seals the gelatinous contents inside. The enclosed fluids perform as a green house capturing the warmth of the sun and protecting the inner contents. The progeny have a buffer from dehydration while eggs. Puddles may dry up around egg masses but if it rains soon the embryos will survive. Once tadpoles, they are not allotted this luxury. If a puddle dries, tadpoles drown in the terrestrial air, not having the lungs to take in atmospheric oxygen. If they can remain wet, the transformation from tadpole to frog is magical, and that is why that transformation is called metamorphosis. A Latin word which means magical change. Tadpoles appear to be all head and tail. The word tadpole comes from two words -- "tad" which means toad and "poll" which means head. In other words, a toad that is all head. Tadpoles seem to be a totally different creatures than the frog or toad they are to become. They breathe with gills. For the most part, they are vegetarians eating with scraping mouth parts that scour the surfaces of rocks and vegetation for algae. In relation to their size, their intestinal tracts are very long to be able to digest cellulose. As time goes on, they develop legs. Back legs first and then front, resulting in a four legged creature. Their intestines shrink. Their gills transform into lungs. Their mouth parts become equipped to eat meat. This includes their incredibly long, fast action, fly-snatching tongue. The time required for these events to occur depends on the species of frog, temperature, food availability, etc. It takes at least one year and sometimes two years for bullfrog tadpoles to metamorphose. Spadefoot toads on the other hand can transform in less than a month. After metamorphosis, the tadpoles become froglets, tiny replicas of their adult parents, who in most cases left the pond after the breeding season and egg laying were complete. Once metamorphosed, many frog species leave the pond or temporary body of water in which they were born. Often times, froglets or toadlets leave the pond in a mass exodus during or immediately following a rain giving the appearance of it raining frogs, as folks once believed. Some species are more permanently aquatic and spend most of their lives in or around the water. Bullfrogs and green frogs are the best examples of aquatic frog species. Courtship and Breeding As adults, the frogs and toads feed and grow, returning to the water annually to breed and lay eggs. Males arrive at the breeding pools first and begin their advertisement call. Frogs make their vocalizations by passing air from their lungs over the vocal chords to the vocal sac, which resonates to make the sound louder. Males vocal chords are larger and more developed than those of females. Each species of frog or toad has a unique advertisement call. Only males sing this courtship song. So unique are these calls that just as birders can identify a bird species by its song, froggers can identify frog species by their calls. Hence, you can know which species of frogs live at your pond without having to see them. 7

8 Once a pair have agreed to breed, male and female frogs enter the mating position. This position is called amplexus. The male clasps the female from behind. He places his front arms around her body and clasps her behind her front legs. Males will often have swollen thumbs so that they can better grip the female. They remain in this position sometimes for several hours. The female releases the eggs and the male bathes the eggs with semen. Both male and female sex and urinary organs are combined in one body part called the cloaca. Fertilization is external. The process sounds sexier than it really is. The eggs are laid. Some frog species lay singular eggs, some lay small masses of eggs, others have large egg masses, and still others lay their eggs in a film across the water s surface. The eggs hatch. Again this takes different amounts of time depending on the species of frog or toad. Communication Frogs and toads give other calls outside courtship. Aggressive calls are territorial messages that are sometimes abrupt, single, loud notes like the bullfrog emits or they can be slurred trills like the spring peeper gives. Aggressive calls send the message to competing males that they are crossing turf boundaries. One can understand how the confusion among male frogs could arise since a spring peeper s territory is only 1 1/2 square feet. Male treefrogs must defend prime perching real estate. A clear perch exactly a certain height directly over the water isn't easy to come by, and females know what they're looking for. Sometimes male grey treefrogs settle for a satellite position in proximity to a prime location. They will wait until the alpha male is busy with a partner and then move in to settle the territory at an opportune moment, while the dominant male is in amplexus (the mating position) with a female. Besides, how is the next female to come along going to know that he didn t get there first? Other calls include the distress call given whenever a frog or toad is being preyed upon. This call is particularly disturbing when a frog is being eaten feet first. Another type of vocalization is a release call. Release calls indicate that whoever has been grabbed wants to be set free. Sometimes this is in the situation of a male clasping a female frog to breed when the female isn't ready and sometimes the release call is emitted when a male frog clasps another male frog. A frog will also emit a release call if a person picks it up. Toads will also wet on you when you pick them up which serves the same purpose. The toad is saying, "Put me down!" Frogs versus Toads "What is the difference between a frog and a toad?" This has been the most asked question since the early days of herpetological study. When herpetology began in Europe (the USA didn't exist yet) the classification of animals was a fledgling practice. European herpetologists started categorizing anurans by placing them into two categories based on two creatures. One of those animals was a toad Bufo bufo the other was a frog Rana temporaria, a frog very similar to our leopard frog. Those were the only two categories that existed at the time, and as you can imagine, some frogs didn t fit into either category perfectly, contributing to the confusion of frogs and toads. There are some differences that you can take stock in. True toads are now in the genus Anaxyrus. They are the dry, warty anurans that have large parotoid or poison glands on their 8

9 shoulders. They look like they are wearing shoulder pads. These anurans are more terrestrial than most frogs. However, there are other anurans whose common names suggest toads, e.g., narrow-mouthed toads and spadefoot toads, that are considered frogs. These frogs are not true toads of the genus Anaxyrus, but they do possess some of the traits that are characteristic of toads. Like toads, they have short legs and thus hop versus leap. They also have short "squatty" bodies with plump bellies. Keep in mind this is just a human-thing of trying to make the universe fit into our systems of organization. The frogs couldn t care less. The Frogs and Toads of Tennessee There are five families, seven genera, and 21 species of frogs and toads in Tennessee. Family Pelobatidae (Spadefoots) Bufonidae (True Toads) Hylidae (Treefrogs) Microhylidae (Narrow-mouthed Toads) Genera Scaphiopus (Spadefoot) Anaxyrus (North American Toads) Acris (Cricket Frogs), Hyla (Treefrogs), Pseudacris (Chorus Frogs) Gastrophryne (Narrow-mouthed Toad) Ranidae (True Frogs) Lithobates (True Frogs) You may be wondering what happened to the toad genus Bufo and the frog genus Rana. Taxonomy is the classification of organisms based on natural relationships. Taxonomists are scientists who continue to arrange and rearrange the order of organisms as more is discovered about them. Taxonomists have determined that North American toads belong to the genus Anaxyrus (Greek for Chief or King) and North American frogs belong to the genus Lithobates. Lithobates is Greek; litho means "a stone," bates means "one that walks or haunts." Thus Lithobates means "rock walker." 9

10 Family Bufonidae -- True Toads Toads are in the family Bufonidae that includes 25 genera and 339 species worldwide. The family is cosmopolitan except for Antarctica, Greenland, New Guinea, Madagascar, Australia and New Zealand. Anaxyrus is the only genus of this family that occurs in North America where it is represented by 21 species and several subspecies. Texas has more toads than any other state. Tennessee has two species of toads -- Anaxyrus americanus, the American Toad and Anaxyrus fowleri, Fowler s Toad. Both species have many colloquial names including garden toad, hop toad and toad frog. All true toads in the U.S. are now in the genus Anaxyrus and have the following characteristics: Two parotoid glands -- large poison glands on the shoulders, Cranial crests -- raised ridges on the back of the head, Horizontal pupils, Scant webbing on the hind feet and One large and one small spade on the rear feet for digging. One could confuse Eastern Spadefoot Toads (Scaphiopus holbrookii) with the true toads. However, they have vertical pupils, only one large spade on each rear foot, smoother, darker skin and much less developed parotoid glands. To distinguish toads in Tennessee, look at the number of warts per dorsal spot, the relationship of the cranial crests to the parotoid gland, the development of the cranial crest and if there are enlarged warts on the thigh. American Toad -- Anaxyrus americanus Voice: Call is a long high trill that can be heard February through the summer months, particularly at higher elevations. Habitat and Habits: Backyards, Gardens, Fields. Often breeds in temporary pools of water, i.e. puddles. Description: Size inches, (record 4.4 inches) A. americanus is a medium-sized brown, tan or reddish toad with prominent parotoid glands behind the eyes. Paratoid glands do not touch cranial crest or are connected only by a spur. American toads have one or two warts in each dark spot. Their eggs are laid in a helical string. Fowlers Toad -- Anaxyrus fowleri Voice: Call is a raspy Waaaaaa that sounds a little like a baby crying. The call of the Fowler s toad makes it seem like the toad is farther away than it really is. Calling usually begins in May and continues into the summer. 10

11 Habitat and Habits: Fowlers toad often frequents sandy floodplains and river bottoms but occurs in almost every terrestrial habitat, including roadsides, backyards, fields, pastures and gardens. It breeds in more permanent waters, i.e. ponds, lakes, streams. Description: Size inches (record 3.7) Medium sized tan, brown or reddish brown toad with dry warty skin. The large parotoid glands touch the cranial crests. There are more than two warts in each dark spot on its skin. The following comparison chart should reinforce the differences between American Toads and Fowler s Toads. American Toad Fowler s Toad 1-2 warts per dorsal spot 3 or more warts per dorsal spot cranial crests do not touch parotoid glands, or if so, by a spur parotoid glands kidney shaped cranial crests prominent chest and underparts mottled long musical trill enlarged warts on tibias typically breeds in March Often breeds in temporary water, e.g., puddles cranial crests touch parotoid glands parotoid glands oblong cranial crests slight underparts clear except for on central breast spot short harsh cry no enlarged warts on tibias typically breed April-July breeds in more permanent waters, e.g., ponds, lakes, streams 11

12 Family Hylidae -- Treefrogs The family Hylidae includes treefrogs, chorus frogs and cricket frogs. It consists of 37 genera containing 637 species. Members occur in tropical and temperate regions worldwide. They are more common in Central and South America and seem to have originated in the tropics and spread northward and southward toward the temperate regions. There are five genera of Hylids in North America -- Hyla (Treefrogs), Osteopilus (Cuban Treefrog), Smilisca (Mexican Treefrog), Acris (Cricket Frogs), and Pseudacris (Chorus Frogs). Representatives live throughout North America except for the most arid deserts and the most frozen arctic. There are reports of Upland Chorus Frogs living at the Arctic Circle. The smallest Hylid in North America is the Least Tree Frog measuring 5/8 inch. The largest is the Cuban Treefrog reaching up to 5 1/2 inches. Female Hylids are larger than males. Acris, Hyla and Pseudacris are the three genera of Hylids in Tennessee. These genera are represented by the following 10 species in Tennessee. Acris gryllus -- Southern Cricket Frog Acris crepitans -- Northern Cricket Frog Hyla avivoca -- Bird-voiced Treefrog Hyla chrysoscelis -- Cope s Gray Treefrog Hyla cinerea -- Green Treefrog Hyla gratiosa -- Barking Treefrog Hyla versicolor -- Gray Treefrog Pseudacris brachyphona -- Mountain Chorus Frog Pseudacris crucifer -- Spring Peeper Pseudacris feriarum -- Southeastern Chorus Frog All North American Hylids have an intercalary disc -- a short extra cartilage between the toe pad and the last bone of the fingers and toes. This extra cartilage allows the toe pads to swivel and be placed flat against vertical surfaces for climbing. Most Treefrogs (Hyla) are slender waisted with long legs. The Chorus Frogs (Pseudacris) and Cricket Frogs (Acris), however are more terrestrial with shorter legs. Treefrogs also have larger toe pads than the Chorus Frogs and Cricket Frogs. Scientists believe that all members of the Hylidae family originated as tree dwellers but through evolution some lost their toe pads and became terrestrial. Many Hylids have flash colors that help protect them from predators. Flash colors are bold patterns on the backs of the frog s thigh and in the groin region. The flash colors of the Gray Treefrogs are apricot orange with dark, worm-like vermiculations. When the frog is sitting, the folds of the legs conceal the flash colors. The combination of bright colors and bold patterns suddenly flash when the frog lengthens its legs to leap from danger. This bold display catches the predator's eye creating a striking search image for the hunter. When the frog lands in a sitting position, the legs again conceal the bright colors. Searching for the blatant color 12

13 patterns, the predator looses sight of its prey, falling victim to a false search image generated by the frog s protective flash colors. Camouflage also aids in the frog escaping detection. Most of the time, Hylids are the same color as their surroundings. Gray Treefrogs can be the color of lichen covered bark. Cricket Frogs can be the bright green of a duckweed covered pond or the sandy brown of a creek bank. Several species of Hylids seem to be able to change color at will. Temperature, humidity, light and even the mood of the frog may affect its color. Genus Acris -- Cricket Frogs Acris means cricket in Latin. The frogs of this genus are the Cricket Frogs. They are small like crickets, usually measuring less than one inch from their snout to their vent. Their calls are similar to the mechanical sounds of crickets but sound more like tapping chert pebbles together. What is most cricket-like about these frogs is the popping sound that they make when they jump and land in dry leaves or grasses. We always look when we hear this sound hoping for a Cricket Frog but usually finding a grasshopper or cricket. However, one time we followed one of those pops and found a Northern Cricket Frog in January. Cricket Frogs may be overlooked for their size, but their colors are outstanding. They don metallic colors that make them look like glimmering jewels. Yet, they remain beautifully camouflaged because they are often the same color as their environment. They are bright green in a pond covered with duckweed or sienna and tan against the leaf litter of a moist bottomland forest. Their background colors can be brown, tan, gray, green or black. They have a stripe down their back that ranges from tan, yellow, green, burnt-orange to brown. They typically have a dark triangle on the back of their head. The apex of the triangle points down the back. The dorsal stripe and this triangle often form a Y. There is a black horizontal stripe on the back of their thigh. However, you must capture the frog to see this, and that is not easy. Cricket Frogs escape danger, or the inquisitive herpetologist, by leaping. Cricket Frogs can leap vertically up to three feet and horizontally for distances of up to four feet! They often dive into nearby water and hide beneath debris. Sometimes they spring erratically out of reach. On occasion, they leap into the water, reverse their direction and return to the bank where they started. This leaves you peering into the distance finding only empty leaves and bare banks just as fooled as the predators thousands of years before you. Cricket Frogs lead a terrestrial life. Therefore, they have lost the climbing paraphernalia, such as the expanded toe pads, of their Treefrog cousins. Both Cricket Frog species in Tennessee are sometimes called Swamp Cricket Frogs. Both species occur in bottomland wetlands or swamps. They also live along wooded streams, lakes and ponds. They prefer aquatic habitats that are exposed to the sun part of the day and have emergent plants that provide cover. They breed in the warmer months of the year. Singing typically starts in April or May. They sing both day and night and have a strange habit of cranking up a chorus in response to loud, vibrating noises such as a plane flying over or the rumble of a passing train. 13

14 Similar Species: It is easy to distinguish Cricket Frogs (Acris) from the Treefrogs (Hyla) because Cricket Frogs lack the expanded toe pads of the Treefrogs. To separate Cricket Frogs from Chorus Frogs (Pseudacris) use the characteristics in the following chart. pointed snout Acris (Cricket Frogs) small warts on body no webbing on fingers but broadlywebbed toes well-defined dark triangle on back of head black horizontal stripe on back of thigh Pseudacris (Chorus Frogs) rounded snout no warts no webbing on fingers or toes if dark triangle occurs on back of head, it is not well defined no black stripe on back of thigh Northern Cricket Frog -- Acris crepitans Voice: Call sounds like two stones being tapped together. The tempo of the tapping sounds speed up during the call then slows back down. The calling usually begins in late March or early April and continues into the summer. Habitat and Habits: A. crepitans can be found at pond margins and stream borders. Description: Size inches Cricket frogs are the smallest frogs in Tennessee. Have a dark triangle between eyes and usually a dorsal stripe. More than ½ of longest toe on rear foot webbed Many color variations Southern Cricket Frog -- Acris gryllus Voice: Call sounds like two stones being tapped together. The call of the Southern Cricket Frog has a heavier inflection than the Northern Cricket Frog. Also the tempo of the tapping sounds does not speed up, it remains constant. Calling usually begins in late March or early April and continues into the summer. Habitat and Habits: A. gryllus occurs at the edges of permanent ponds, lakes and slow moving streams. Only occurs in southwest corner of Tennessee. Description: Size inches, Cricket frogs are the smallest frogs in Tennessee. A small frog with a dark triangle between the eyes and usually a dorsal stripe. There are many color variations to this frog with the frog often mimicking the color scheme of the environment where they live. Less than ½ of longest toe on rear foot is webbed. 14

15 Distinguishing characteristics of the two cricket frog species are compared in the chart below. pointed snout Acris gryllus 1st rear toe partially webbed, 4th rear toe (longest) with 3 joints free smooth dark stripe on rear of thigh when rear leg is extended alongside body, the heel surpasses the snout no prominent pair of anal warts usually found in temporary pools near permanent water typically occurs in southwest corner of Tennessee bluntly pointed snout Acris crepitans 1st rear toe completely webbed, 4th rear toe (longest) with only 1.5 to 2 joints free ragged dark stripe on rear of thigh when rear leg extended thusly, heel does not surpass the snout prominent pair of anal warts usually found on shore of permanent water occurs nearly statewide The restricted range of the Southern Cricket Frog and the amount of toe webbing are the easiest ways to distinguish these two species. Because of their small size, one might confuse the cricket frogs with the chorus frogs, but the latter have a white stripe across their upper jaw and no webbing on their rear feet. 15

16 Genus Pseudacris Chorus Frogs The chorus frog genus was once Chorophilus from the Greek words choro, a band of dancers or singers (a chorus) and phileo, love -- lover of the chorus. On the first warm evenings of February after the pre-spring rains it is easy to understand the origin of this name. The chorus frog assemblies are so loud and well attended that they herald the imminent arrival of spring, even though there may be six more weeks of winter. Pseudacris is combines the Greek pseudes, false, and akris, a locust. This generic name refers to the similarity of the chorus frogs (Pseudacris) to the cricket frogs (Acris). There are three similar species. Pseudacris brachyphona Pseudacris feriarum Pseudacris crucifer backwards parenthesis on back 3 broken stripes on back cross on back call: fast, short reek-rake finger down comb teeth loud peep dark mask like Wood Frog no dark mask no dark mask Mountain Chorus Frog -- Pseudacris brachyphona Voice: Call is short, raspy and rises in pitch. The call is similar to call of Upland Chorus Frog but faster and shorter. Call can be heard February through August. Peak calling February and March. Habitat and Habits: Found in wooded habitats at the higher elevations of Cumberland Plateau and the eastern mountains. Mountain Chorus Frogs breed in flooded roadside ditches, pools along streams and wheel ruts in gravel roads. Eggs are laid on the petiole of a leaf in shallow water. Description: Size inches, (record 1.5 inches) A small chorus frog marked in shades of tan and black. Reverse Parentheses on back, mask behind eye, white line over lip. This frog resembles a miniature Wood Frog. Southeastern Chorus Frog -- Pseudacris feriarum Voice: Call is short, raspy and rises in pitch. The call sounds like someone dragging their thumbnail over the teeth of a comb. Full breeding choruses start in December and continuing through the winter into spring and summer. Isolated individuals call from the trees during the fall. These calls are known as rain calls. Habitat and Habitats: P. feriarum breed in flooded fields and ditches. Egg mass is approximately 1-1/2 inches long, and embryos are approximately 1/16 inch in diameter. Eggs are typically attached to blades of grass and other vegetation. Description: Size inches. A small, tan to light brown frog with three darker stripes (sometimes broken) running down its back. A dark triangle occurs between the eyes. 16

17 Spring Peeper -- Pseudacris crucifer Voice: Call is a short, high exuberant peep that rises slightly at the end a high piping whistle. In the eastern mountains have been heard every month of the year. Full breeding choruses usually begin in late January and continue well into the summer. Isolated individuals call from the trees during the fall. Habitat and Habits: Wet fields bordered by trees. Description: Size inches, (record 1.5 inches). P. crucifer is a small, tan to light orange-brown frog. Stripes form a cross on its back. There is a dark line between the eyes. Toe pads are slightly enlarged. Genus Hyla -- Treefrogs The genus Hyla contains the true treefrogs, frogs adapted for life in the trees. These adaptations include pronounced sticky toepads that help them cling to tree trunks and branches and an obvious intercalary disc that allows the toepads to swivel for better contact with vertical surfaces. They also have long legs for climbing. Their fingers are somewhat webbed and their skin is granular. Many species even use loose skin on their bellies to help them stick to slick surfaces. People have reported species of Hyla clinging to windows while hunting insects attracted to indoor lights. Many Hyla species are adept at changing color, hence names such as versicolor. These color changes may depend on light, moisture, temperature, stress, or activity. During their emergence, many Hyla froglets don a solid, bright green livery that camouflages them amidst grass and other vegetation surrounding breeding pools. Many members of this genus only come down to the ground to breed. Afterwards, they return to the shrubs and trees of swamps, moist woods, and thickets. Members of Hyla occur throughout the range of the Hylidae family, except for Australia and New Guinea. We have five species in the genus Hyla in Tennessee: Hyla avivoca -- Bird-voiced Treefrog Hyla chrysoscelis -- Cope s Gray Treefrog Hyla cinerea -- Green Treefrog Hyla gratiosa -- Barking Treefrog Hyla versicolor -- Gray Treefrog 17

18 Gray Treefrog Complex -- Hyla chrysoscelis and Hyla versicolor Note: Cope s Gray Treefrog cannot be distinguished from the Gray Treefrog visually. They must be identified by analyzing the pulse rate of the call at a standard temperature. Voice: Call is a short raspy trill. Recording the call and ambient temperature allows computer analysis to tell species. Calling usually begins in March and continues throughout the summer. Habitat and Habits: Breed in wetlands and small pools. This species is arboreal outside of breeding season. Description: Size inches (record 2.4) Gray Treefrogs are small green to gray-green treefrogs with enlarged toepads. There is a white rectangle beneath eye. The back is mottled. The backs of the thighs are washed in orange flash colors. Birdvoiced Treefrog -- Hyla avivoca Voice: Call is a series of short birdlike whistles. Calling usually begins in late May and June and continues throughout the summer. Habitat and Habits: H. avivoca breeds in wetlands and sloughs. This species is arboreal outside of breeding season. Description: Size inches (record 2.1) Birdvoiced Treefrogs are small green to gray-green treefrogs with enlarged toe pads. There is a white rectangle beneath eye. The back is mottled. The flash colors on thighs are light transparent green. Similar Species: Gray Treefrogs and Birdvoiced Treefrogs can be distinguished by the flash colors. Gray Treefrogs have bright, apricot orange flash colors. Birdvoiced Treefrogs have light, transparent green flash colors. Barking Treefrog -- Hyla gratiosa Voice: Call is a short hollow-sounding bark that sounds like a beagle on the trail of a rabbit that can be heard from June through August. Also makes a short raspy call from the tree canopy. One of our latest frogs to breed requires higher ambient temperatures. Habitat and Habits: Variety of habitats from cypress or sweetgum ponds to flooded cultivated fields. Description: Size inches (record 2.7). H. gratiosa is our largest treefrog. They are bright green with yellow stripe on sides with large toepads. May or may not have dark spots on back. Note coarse granulation of skin on back compare to granulation on belly. 18

19 Green Treefrog -- Hyla cinerea Voice: Call is a short nasal quonk. Call from May to August. Habitat and Habits: Prefer the permanent waters of cypress swamps, marshes and river sloughs. This species is expanding into other habitats across the state. Description: Size inches (record 2.5) H. cinerea is a bright green treefrog with yellowish stripe down the side. Note toepads. Note fine granulation of skin on back compare to coarser granulation on belly Similar Species: The frog most similar to the Green Treefrog, Hyla cinerea, in Tennessee is the Barking Treefrog, Hyla gratiosa. These two species can be so similar that they have been confused in past literature reports. Preserved specimens have even been misidentified and labeled as the other species in museum collections. They are both large, green treefrogs but there are differences in their physical appearances, habitats and habits. The Barking Treefrog is the larger (2 3/4 inches) of the two but this is difficult to determine without the two species side by side. The Barking Treefrog can also have conspicuous round, dark spots but the spots are often indistinct. The Green Treefrog never has dark round spots on the back. The side stripe of H. cinerea is more sharply defined compared to the more broken and irregular stripe of H. gratiosa. The best way to separate these species however, is to compare the degree of granulation on the belly to that of the back. Hyla gratiosa s back has the same amount of granulation as its belly. Both the back and belly appear pebbly. Hyla cinerea s back is much smoother than its belly. They also seem to prefer different habitats. Sometimes the ranges of these two species overlap but much of the time Hyla cinerea occurs in areas where H. gratiosa is rarely seen such as river swamps and permanent lakes. Barking Treefrogs also occur in much smaller breeding choruses than Green Treefrogs and mostly breed in sink ponds that can either be permanent or temporary. Their breeding behaviors are also different. Males of Hyla cinerea emit the mating call from out of the water on overhanging branches and shrubs whereas Hyla gratiosa males give this call while floating in the water. 19

20 Family Microhylidae -- Narrow-mouthed Toads This family contains 55 genera and includes 215 species. In the United States, this group is represented by two genera and three species. i Gastrophryne carolinensis, the Eastern Narrowmouthed Toad, is the only species of Microhylidae in Tennessee. The old generic name for this group was Engystomatidae; meaning contracted or constricted mouth referring to the frogs narrow mouths. The upper jaw of this group is toothless. There is no webbing on the toes and the tympanum is hidden. The Gastrophryne genus is closely related to the genus Hypopachus the Sheep Frogs. Most members of this family are fossorial meaning that they spend most of their time in burrows, under rocks or logs. They have enlarged tubercles on their hind feet for digging. They are small and plump with a narrow pointed head. They have short legs that make them hop instead of leap. This combined with their plump physique is why they are called toads even though they are not members of the genus Anaxyrus. They have a characteristic fold of skin across the back of their head that can be pulled forward to protect their eyes from their favorite food, ants. Other members of the family occur in Mexico, Central and South America, Africa, Asia, the Indo-Australian archipelago and Northern Australia. The family apparently originated in Southeast Asia and has spread to New Guinea, Africa, Madagascar and the Americas. Eastern Narrow-mouthed Toad -- Gastrophryne carolinensis Voice: Call is a long drawn-out, high-pitched, nasal insect-like Beeeeeeee. Many liken the call to the cry of newborn lambs or New Year s Eve party horns. Call from April to October. Habitat and Habits: Narrow-mouthed Toads live in a variety of habitats including old fields and cedar glades. Breeding areas are temporarily flooded fields and ditches. Description: Size inches (record 1.5) G. carolinensis is a small potbellied anuran with a tiny turtle-like head and a pointed snout. This is the only frog or toad in Tennessee that has round pupils. A fold of skin runs behind the eyes and can be pulled over the eyes while eating dangerous prey such ants. Colors are tan and brown with gray belly. 20

21 Family Pelobatidae -- Spadefoot Toads The name Pelobatidae comes from the Greek word pelos that means earth and the Latin word batillum meaning shovel. Members of this family live a mostly fossorial or underground existence. They bury themselves into the earth backwards with a sharp spade on their rear feet. Spadefoots are well suited for arid environments. They are explosive breeders with short larval periods, both adaptations for scarce rains and ephemeral breeding pools. Spadefoots come above ground to breed after heavy rains often associated with violent weather such as tornadoes. Amplexus is inguinal meaning that the male grasps the female in front of the hind legs instead of behind the front legs like other frogs of our area. Spadefoots are truly nocturnal and thus have vertical pupils giving them an otherworldly look. Members of this family are often called spadefoot toads. They have smaller versions of parotoid glands like toads but they have mostly smooth skin and teeth in their upper jaw, which is very different from toads. Spadefoots also have only one spade whereas toads have two spades on their back feet. The family Pelobatidae is divided into two families, the Megophrinae and the Pelobatinae. The Megophrinae only occurs in the Far East and includes such bizarre creatures as the Asiatic Horned Frog of Indonesia. Each upper eyelid of this frog extends forward and upward to form a long, thin pointed horn and there is a long, flexible projection of the snout, thus the animal appears to have three horns. The spadefoots of Europe, North Africa, and North America make up the second subfamily, Pelobatinae. This subfamily includes the genus of our spadefoots, Scaphiopus. Scaphiopus is the only genus of Pelobatidae in North America and includes five species. The name Scaphiopus comes from scaphi spade and opus foot. The Eastern Spadefoot Scaphiopus holbrookii is the only species of this genus east of the Mississippi River. Eastern Spadefoot -- Scaphiopus holbrookii Voice: Call is a strange sounding downward slurred errrrrgh. Call sounds somewhat like a young crow. Habitat and Habits: Eastern Spadefoots are subterranean, coming above ground in wet weather to breed and forage. Breeding areas are temporary pools formed by warm weather thunderstorms and is usually of short duration. Eastern Spadefoots burrow by backing their way into the hole, making sweeping digging movements with their rear feet. Description: Size inches (record 2.8) Note the plump-bellied, humpbacked look. Spadefoot Toads are toad-like in shape but smoother-skinned. The skin is dark with red warts sometimes with a light lyre shape on the back. Small parotoid glands are present. These are not near as large as the parotodi glands of true toads. Spadefoot Toads are Tennessee s only anurans with vertical pupils that appear diamond shaped. There is 1 spade on the underside of their rear feet. 21

22 Family Ranidae True Frogs There are seven Ranids in Tennessee. They are all currently in the genus Lithobates. Lithobates areolata Northern Crawfish Frog Lithobates capito Gopher Frog Lithobates catesbeiana Bullfrog Lithobates clamitans Green Frog Lithobates palustris Pickerel Frog Lithobates sphenocephala utricularius Southern Leopard Frog Lithobates sylvatica Wood Frog In the unrestricted use of the word, all frogs and toads are frogs. However, species in the genus Lithobates are considered true frogs. These are the long legged frogs with a narrow waist and smooth skin. The hind toes are webbed. A glandular fold of skin extends down each side of the back on all species except the Bullfrog. The upper jaw contains teeth. These are our largest frogs, the Bullfrog being our largest native North American anuran, outsized only by the introduced Marine Toad. The Bullfrog has been the lab frog used for dissection in the past. The webbing of leopard frog feet has been used in physiology lab experiments to demonstrate forced movement. Today, leopard frogs are the choice species for frog dissection. Bullfrogs are the only frogs legally hunted in Tennessee for the edible frog legs. American Bullfrog -- Lithobates catesbeiana Voice: Call is a deep jug-a-rum. Calls usually begin in March and continue through August. Habitat and Habits: Permanent ponds and other bodies of water. Description: Size inches (record 8.0). Bullfrogs are the largest frogs in Tennessee. The dorsolateral ridge curves around the tympanum but does not extend down back. Males have yellow throats during breeding season. The size of the tympanum relative to the eye indicates sex. If the tympanum is equal to the size of the eye the individual is a female. If the tympanum is larger than the eye the individual is a male. Green Frog -- Lithobates clamitans Voice: Call sounds Like a loose banjo string being plucked a short, explosive glunk! This call can be given singly or in a series of two to five notes. Calls March through September. Habitat and Habits: Occurs in permanent bodies of water including creeks, rivers, springs, sloughs, reservoirs and ponds. 22

23 Description: Size inches (record 4.2) The dorsolateral ridge extends down the back and around the tympanum. Males have a yellow throat during the breeding season. Like Bullfrogs, if tympanum is larger than eye the sex is male. If tympanum is about equal to eye the sex is female. Some individuals can be a bronze color all over Southern Leopard Frog -- Lithobates sphenocephalus Voice: Call is a series of clucks interspersed with groans that sound like a hand being rubbed over a balloon. The call sounds like laughter at a distance. L. sphenocephalus calls from January into the summer months, and again in the fall. Egg masses can be found in both spring and fall. Habitat and Habits: Southern Leopard Frogs live in ponds and sloughs. They are sometimes called grass frogs because they venture far from water in wet grassy areas. Description: Size inches, (record 5.0 inches) These are medium-sized green or brown frog randomly spotted with dark spots. Note the light spot in the center of the tympanum. Pickerel Frog -- Lithobates palustris Voice: The advertisement call of the Pickerel Frog is a long, descending snore yeeeeoooow that can be heard March through April, with a peak in early April. Habitat and Habits: Ponds with dense vegetation and cover. This frog can often be found in the twilight zone of caves and the cool water of springs. Description: Size inches, (record 3.5 inches) The Pickerel Frog is one of the most beautiful frogs in Tennessee, with an array of rectangular spots on its bronze to tan back. Apricot orange flash colors on the groin are concealed by the thighs when the frog is at rest. Note that there is no white spot in the tympanum or ear drum. Wood Frog -- Lithobates sylvatica Voice: Call is a series of clucks similar to Southern Leopard Frog, but more random in delivery with little carrying power. Habitat and Habits: Upland deciduous woods. Breeding takes place in woodland ponds, ruts in woodland roads and roadside ditches. Breeds explosively early in the year, as soon as the first warm rains in January. Breeding can extend into February. Egg masses can be found in large clusters during the winter months. Red-spotted Newts are among the predators that prey on the eggs. 23

24 Description: Size inches, (record 3.2 inches). L. sylvatica is a medium-sized tan to dark brown frog with a dark mask behind the eye and a white line over the lip. Flash colors on the groin are a pale yellow-orange. The body is mostly unmarked. Crawfish Frog -- Lithobates areolatus Voice: Call is deep, snoring Waaaa with tremendous carrying power. Breeding choruses start in late February and continue into March. Habitat and Habits: Inhabits crawfish burrows and the burrows of small animals. Breeds in small ponds and water-filled borrow pits. Description: Size inches, (record 3.6 inches). This is a bulky, rather strange looking frog. Skin color varies from cream colored to dark brown, with dark brown spots encircled by a white border. The dorsolateral ridges are very prominent. The belly is whitish. Gopher Frog -- Lithobates capito Voice: Call is a deep, drawn out snore or growl. Often calls from underwater. Has not been heard calling in Tennessee. Habitat and Habits: Poorly known in Tennessee. R. capito is known from only one wetland near Tullahoma. When picked up often places its hands over its eyes. Description: Size inches, (record 3.9 inches). This is a medium-sized stout-looking frog with very prominent dorsolateral ridges and a pronounced sacral hump. The throat and belly are mottled, unlike the Crawfish Frog. Conservation Concerns Frogs and toads are declining world wide and there are many reasons for this. Disease is a major factor in the disappearance of entire populations of frogs in the tropics. The main culprits are the Chytrid fungus and Rana virus. However, in Tennessee the number one cause for all wildlife declines is habitat loss. The loss of wetlands is critical for amphibians. We should make every opportunity possible to conserve wetlands and other aquatic habitats across the state. Amphibians as Bio-indicators Amphibians living in wetlands, ponds, or streams are completely bathed in the medium of their environment. They absorb water and breathe through their skin and cloaca. Frogs, toads and salamanders are sensitive to factors that degrade the environment. Silt, pesticides, herbicides, fungicides, hormone mimics, pathogens and parasites negatively affect amphibians. Larger, widespread issues such as climate change and ultra violet radiation exposure can weaken the immunity of amphibians making them more susceptible to such harmful 24

25 environmental factors. Because of this intimate connection with their environment, amphibians make excellent indicators of the integrity of aquatic ecosystems. Here s an example. Poisons such as pesticides can enter the bloodstream of amphibians directly through their skin. Insect repellants that humans spray, douse and lather all over their bodies are deadly to frogs and salamanders. This is why amphibians, much like the canary in the mine shaft, can indicate toxic conditions in aquatic habitats long before humans would be aware of any danger. If amphibians in an area perish, are deformed or cannot reproduce successfully this should serve as a warning that the environs are unhealthy. Sources: Souder, William A Plague of Frogs, The Horrifying True Story. Hyperion, New York. Pp Images and Calls To see and hear Tennessee s 21 species of frogs and toads, visit 25

26 II and III. Amphibians -- Order Caudata, Salamanders The salamanders section of this guide was taken from a paper titled Spring Lizards in Tennessee or What the Heck is a Desmognathus fuscus? compiled by Pete Wyatt, East Tennessee TWRA Nongame/ Endangered Species Coordinator with permission for use by the Tennessee Naturalist Program. Salamanders are amphibians and lizards are reptiles. In a topographic sense one might resemble the other. Each usually has four legs, a noticeable torso, and a distinct tail. Lizards, the reptiles, have external ear openings, dry scaly skin and claws on their toes. Salamanders, the amphibians, do not have external ear openings and do not have dry skin but smooth, rubbery textured moist skin and no claws on their toes. Lizards lay shelled eggs deposited in a nest with incubation being done by the sun. Salamanders lay their eggs either in the water or in a moist cavity sheltered from the sun, and in many species the female provides some care of the eggs and larvae, but no true incubation by the female occurs. Almost all salamanders are voiceless. The chemical messengers (pheromones) secreted by hedonic glands evoke courtship and spawning behavior. Fertilization is external in the hellbender and the siren. In all other species it is internal. The male deposits a packet of sperm on a gelatinous stalk (spermatophore), and the female clasps it with her cloaca. The sperm remain in her cloaca in blind sacs (spermathecae) until the extrusion of the eggs from her ovaries, which brings the sperm and egg cells together in the oviducts. This type of fertilization is found in all species of Tennessee salamanders except the hellbender and siren. In these species, the male covers the eggs with seminal fluid after they are laid. Female salamanders deposit their eggs in a variety of arrangements and locations. The eggs may be deposited singly, or in a cluster held together by gelatinous envelopes, or in masses. Locations include underground burrows, rotten logs, sandstone crevices, or caverns, sphagnum bogs, ponds, seepages, and streamside debris or tunnels. Salamanders typically undergo an aquatic larval stage lasting from a few days to several years, but in the terrestrial plethodontids the larval stage is completed within the egg membrane prior to hatching. The larvae stage ends with metamorphosis, a series of definitive changes in structure and life cycle. Adults of some species retain numerous larval features; the siren and mudpuppies are classical examples, each retaining their gills. Some species of salamanders are totally aquatic, some salamanders live in moist places on land but go into the water to breed, and others are completely terrestrial. Surprisingly, few are arboreal, possibly that habitat is too hostile although in the Appalachians of east Tennessee rainfall is higher than other parts of the state and the tiny pigmy salamander is a semi-tree dweller. Most are nocturnal and remain hidden under logs and rocks or in their burrows during the day. 26