Reptiles Note: These links do not work. Use the links within the outline to access the images in the popup windows. This text is the same as the scrolling text in the popup windows.. Introduction (Page 1) Hard Shell: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/reptiles/reptiles_popups/hard_shell.html This diagram shows a turtle s shell sawed in half. Notice that the upper part, called the carapace, is composed of vertebrae and ribs that are fused together with a layer of other bone on top. The bottom part o he shell, called the plastron, consists of several bones. The bony girdles, to which the limbs attach, are ocated completely inside the ribs. In all other vertebrates the girdles are outside the ribs. Freshwater: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/reptiles/reptiles_popups/freshwater.html This picture is of a freshwater turtle. Marine: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/reptiles/reptiles_popups/marine.html This is a loggerhead turtle, one of the marine species. Terrestrial: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/reptiles/reptiles_popups/terrestrial.html This is a large terrestrial tortoise. Notice its club-shaped feet. These turtles live well over a hundred years. Crocodiles: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/reptiles/reptiles_popups/crocodiles.html This is a salt-water crocodile. Alligators: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/reptiles/reptiles_popups/alligators.html This is the American alligator at home in the Everglades. Caiman: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/reptiles/reptiles_popups/caiman.html This is a caiman, a close relative of the alligator. Gavial: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/reptiles/reptiles_popups/gavial.html This crocodilian with a long, narrow snout is a gavial. It lives in India and eats fish. Voracious Predator: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/reptiles/reptiles_popups/voracious_predator.html
This Nile Crocodile is attacking a wildebeest that has come to the river to drink. Tautaras: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/reptiles/reptiles_popups/tuataras.html
This is not a lizard. It is a tuatara, a remnant of a previously abundant group of reptiles, most of whose members became extinct millions of years ago. Spurs: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/reptiles/reptiles_popups/spurs.html There are fossils of extinct snakes that had legs. The only remnants of legs remaining in living snakes, however, are these small spurs in male pythons. These are accessory to mating and do not function in ocomotion. Legless: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/reptiles/reptiles_popups/legless.html Although these four species are very snake-like in appearance, they are actually lizards. Eyelids: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/reptiles/reptiles_popups/eyelids.html This is a horned lizard. Notice the eyelids that can open and close. Tongue: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/reptiles/reptiles_popups/tongue.html When the transparent scale covering a gecko s eyelid gets dusty, it merely washes it with its tongue! Snails: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/reptiles/reptiles_popups/snails.html This South American lizard has a specialized diet of snails. Here you can see one in the act of crushing a snail s shell. Predatory: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/reptiles/reptiles_popups/predatory.html This python is just beginning to swallow an impala that it has just killed. Constriction: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/reptiles/reptiles_popups/constriction.html This anaconda is constricting a caiman. A constricting snake wraps around its prey and when its victim exhales it tightens its coils preventing inhalation, eventually asphyxiating the prey. Constriction may also estrict blood-flow to vital organs. Venom: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/reptiles/reptiles_popups/venom.html This photograph shows a viper striking. Notice the large fangs in the front of the mouth. When the snake opens it mouth wide, the fangs are erected and point forward, as shown here. On contact with the victim, venom is injected by these hypodermic-like fangs. Venomous: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/reptiles/reptiles_popups/venomous.html This attractive lizard is the Gila Monster, one of the two species of venomous lizards. I. Emancipation from water (Page 2)
Cleidoic Egg: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/reptiles/reptiles_popups/cleidoic_egg.html This diagram shows the features of a cleidoic egg. There is an outer protrective shell. Inside it the embryo develops within a fluid-filled, membranous sack called the amnion. In essence, the embryo is still developing in an aquatic medium. It has merely brought its small pond out on land with it. A yolk sac is attached to the gut and provides yolk for food. The allantois is another membranous sac. It stores wastes. t is also vascularized (that it, it has blood vessels) and this membrane, as well as an all-enveloping one called the chorion are involved in respiration. The albumen is a source of water. II. Reproduction (Page 3) Digs: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/reptiles/reptiles_popups/digs.html This female sea turtle has come ashore to lay her eggs. In the upper part of the photograph you can see her rack leading up the beach to the nest hole she is digging. Notice the spray of sand kicked up by her front lipper as she digs a broad body pit. Next she will use her hind flippers to excavate a deep cylindrical pit fo he eggs. Deposits: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/reptiles/reptiles_popups/deposits.html This photograph looks down into the egg pit where the sea turtle is depositing her egg. Covers: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/reptiles/reptiles_popups/covers.html This sea turtle has laid her eggs and is now using her front flippers to cover them with sand Emerge: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/reptiles/reptiles_popups/emerge.html When the young sea turtles hatch they dig their way to the surface where they all emerge at once. They run he hazardous gauntlet of crabs and seabirds toward the sea and the waiting sharks. There is a large toll exacted by these predators and few of the hatchlings survive to reach the relative safety of the open sea. Even fewer live to become adults and return to nest on the beach where they hatched. Penis: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/reptiles/reptiles_popups/penis.html This is a crocodile with its single penis protruding from the cloaca. Hemipenes: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/reptiles/reptiles_popups/hemipenes.html These drawings are of a hemipenis of each of four different species of snakes. Each animal has another hemipenis like a mirror-image on the opposite side. The groove on the underside is the conduit for the sperm. The hooks and spines serve to prevent dislodgement until after ejaculation has taken place. Each species has its own characteristic types and arrangements of these projections. The hemipenis is bag-like and when not in use is inverted in a sheath in the tail just behind vent. Lizards: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/reptiles/reptiles_popups/lizards.html Here is a lizard with two eggs she has just laid.
Snakes: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/reptiles/reptiles_popups/snakes.html These are snake eggs in the process of hatching. Several hatchlings have already emerged and their empty shells can be seen. In eggs that have not yet hatched the outline of the hatchling is visible. V. Ectothermism and endothermism (Page 4) V. Locomotion (Page 5) Paddle-shaped Tail: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/reptiles/reptiles_popups/paddle_shaped.html This is a sea-krait, one of the few sea snakes that ever comes out on land. Notice the flat, paddle-shaped ail. It provides better propulsion during swimming. Feed on Algae: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/reptiles/reptiles_popups/feed_on_algae.html The Marine Iguana of the Galapagos Islands is the only truly marine lizard. In the upper picture there is one swimming at the surface. The picture below illustrates one feeding on algae at the bottom of the sea. Bipedally: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/reptiles/reptiles_popups/bipedally.html This basilisk is running on its hind legs only. The body leans forward but is counter-balanced by the long ail. Side-winding: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/reptiles/reptiles_popups/side_winding.html Side-winding is a type of locomotion in which the head and front of the body is raised and looped over to gain purchase some distance away; the loop then progresses backward as the body is straightened out, so hat the animal appears to "roll" along the substrate. This method is effective on loose substrates such as dry sand. Side-winding leaves very distinctive tracks, as shown here. Expanded Pads: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/reptiles/reptiles_popups/expanded_pads.html You are looking through a vertical pane of glass at a gecko adhering on the other side. Notice the large, expanded toe-pads that give it the grip it needs to adhere to such smooth surfaces. Ribs: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/reptiles/reptiles_popups/ribs.html These views are of a flying-lizard. On the left the lizard is clinging to a tree trunk and has its so-called wings folded beside the body. On the right you can see the animal gliding through the air with its wings extended. These wings are extensions of the ribs with skin stretched between them. VI. Sensory Perception (Page 6) Ear: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/reptiles/reptiles_popups/ear.html
Crocodiles have an opening to the ear that is being demonstrated here by a person holding open a flap of
skin covering it. Protrude: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/reptiles/reptiles_popups/protrude.html This rattlesnake is protruding its tongue in order to be able to smell. The tongue does not detect odors itself but rather transmits them to a sensory pit, called Jacobsen s organ, in the roof of the mouth. When the ongue is extended, odoriferous chemicals in the air dissolve in its moist membranes. The snake then retracts ts tongue and puts the forked tip into the Jacobsen's organ where the odors are detected. Snake-like Tongue: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/reptiles/reptiles_popups/snake-like_tongue.html This is a Gila Monster. It is one of the lizards that has a snake-like tongue. Like snakes, it uses the tongue o transmit odors from the air to the Jacobsen s organ. Lips: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/reptiles/reptiles_popups/lips.html Each of the scales of the upper and lower lips of this emerald boa have a deep, heat-sensitive pit. Using hese they can accurately strike warm-blood prey in the dark. Face: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/reptiles/reptiles_popups/face.html Some vipers like rattlesnakes, cottonmouths and copperheads have a deep pit in the side of the face between he eye and the nostril. These are extremely sensitive to heat and can detect differences in temperature of only a fraction of a degree. Being located on both sides of the head, they operate stereoscopically and even blinded animals, or those in complete darkness, can strike warm blooded prey accurately. VII. Phylogeny of reptiles (Page 7) Anapsid: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/reptiles/reptiles_popups/anapsid.html This diagram shows the three main types of reptilian skulls. A skull with no large opening in the temporal egion is called an anapsid skull. The synapsid skull has one opening low in the temporal region. The diapsid skull has two openings, one high on the skull and the other lower down. VIII. Importance of reptiles to humans (Page 8) Asian Markets: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/reptiles/reptiles_popups/asian_markets.html These monitor lizards were trussed with string and were on sale for food in a city market in Laos. Salt-water Crocodile: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/reptiles/reptiles_popups/salt_water_crocodile.html This map shows the places and dates of attacks on humans by salt-water crocodiles in Australia between 1975 and 1988. Alligator: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/reptiles/reptiles_popups/alligator.html
This map shows the times and dates of alligator attacks on humans in Florida between 1973 and 1988.
Break Down: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/reptiles/reptiles_popups/breakdown.html This picture shows the arm of a person who was bitten on the hand by a venomous snake. been partly digested, exposing the bones of the hand. The tissues have Hemorrhage: http://courses.ncsu.edu/zo495x/common/zo155_site/wrap/reptiles/reptiles_popups/hemorrhage.html The person pictured here was bitten on the hand by a venomous snake. Because of the venom s action in preventing clotting, bleeding was hard to control and blood continued to soak through the bandages long after the bite.