Reptilia

1. Reptilia

2. Characteristics • Body covered with keratinized epidermal scales • Integument with few glands • Two paired limbs, usually with five toes • Adapted for various functions • (climbing, running, paddling, etc) • Skeleton well ossified • Skull with one occipital condyle • a protrusion on the skull that forms a joint that enables movement of the head; allows a wider range of motion

3. Characteristics • Respiration by lungs • Pharynx or skin used by some • Ectotherms • 12 pairs of cranial nerves • Internal fertilization • Eggs coved with calcareous or leathery shells

4. Characteristics that distinguish them from amphibians • Tough, dry, scaly skin • Protection against drying out & physical injury • Chromatophers • Color-bearing cells • Amniotic egg permits rapid development • Jaws designed for applying crushing or gripping force to prey • Some form of copulatory organ permitting internal fertilization

6. Characteristics that distinguish them from amphibians • Efficient & flexible circulatory system & higher blood pressure • Lungs are better developed • Suck air into lungs (amphibians force air into lungs) • Developed efficient strategies for water conservation • Better body support • Limbs designed for life on land • Nervous system more complex

7. Living Reptilian Groups • Order Testudines • turtles • Order Squamata • Snakes, lizards, worm lizards • Order Sphenodonta • Tuataras • Order Crocodilia • Crocodiles & Alligators

8. Turtles: Order Testudines • Enclosed in shells • Shell is fused to thoracic vertebrae & ribs • Protection for the head & appendages • Jaws are provided with tough, keratinized plates (lack teeth) • Poor sound perception & most are mute • Good sense of smell & color vision • Oviparous & internal fertilization

9. Turtles: Order Testudines • Nest temperature determines sex of hatchlings • Low temperatures produce males • High temperatures produce females • Marine turtles can reach great size • Leatherbacks – 2 m (6 feet) & weight up to 900 kg (2,000 lbs) • Most are slow moving & low metabolism

10. A female leatherback sea turtle heaves herself from the surf at night to nest. Females often return to the same nesting areas where they were born to produce their own offspring.

12. Lizards, Snakes, & Worm Lizard: Order Squamata • ~95% of all known living reptiles • Kinetic skull • Movable joints • Enables seizing & manipulating prey

13. Lizards, Snakes, & Worm Lizard: Order Squamata • Lizards • Terrestrial, burrowing, aquatic, arboreal, & aerial members • Includes Geckos, iguanas, skinks, and chameleons • Most have movable eyelids • Keen vision for daylight • Ectothermic

15. Gila Monster

16. Lizards, Snakes, & Worm Lizard: Order Squamata • Snakes • limbless & usually lack both pectoral & pelvic girdles • Numerous vertebrae – shorter & wider than most tetrapods • Highly kinetic skull • Allows snakes to swallow prey several times their own diameter • No movable eyelids & no external ears • Sensitive to vibrations through the ground

18. Lizards, Snakes, & Worm Lizard: Order Squamata • Snakes • Jacobson’s organs • Pitlike organs in the roof of the mouth – lined with olfactory epithelium; richly innervated • Forked tongue • Flicked through the air, picks up scent molecules • Capture prey with mouth & swallow it while it is still alive • Some kill prey first by constriction • Some inject with venom (less than 20% of snakes are venomous)

22. Lizards, Snakes, & Worm Lizard: Order Squamata • Snakes • Family Viperidae • Pit vipers – posses heat-sensitive pit organs between nostrils & eyes • Use pits to track warm-blooded prey & to aim strikes • N. American venomous snakes are pit vipers • Rattlesnake, water moccasin, copperheads • Teeth modified as fangs • Venom injected through a canal in the fangs • Neurotoxic venom • Acts on nervous system; affecting the optic nerves (blindness) or phrenic nerve of diaphragm (paralysis of respiration) • Hemorrhagin venom • Destroys red blood cells & blood vessels

25. Lizards, Snakes, & Worm Lizard: Order Squamata • Snakes • Most are Oviparous • Producing eggs, with a shell, that hatch outside the body. • Some are Ovoviviporous (American pit vipers) • carry the eggs internally and upon delivery of the offspring the entire shell structure has thinned to the point that only the thin mucous membrane remains from which the offspring emerges. • Few are Viviparous • True live-bearing

26. Tuataras: Order Sphenodonta • Sphenos – wedge; odontos – tooth • Lizard-like form (66 cm long) • Slow-growing with long life • Recorded to have lived 77 years • Found only in New Zealand

27. Crocodiles & Alligators: Order Crocodilia • Crocodilians • Elongate, robust, well-reinforced skull & massive jaw musculature • Provides a wide gape & rapid, powerful closure • Complete secondary palate • Allows breathing when mouth is filled • Oviparous • Lays 20-50 eggs • Can weigh up to 1000 kg (~2200 lbs)

31. Crocodiles & Alligators: Order Crocodilia • Alligators • Less aggressive • Alligators have wider, U-shaped snouts is more pointed and V-shaped

32. Continental Reptiles Research • Research the reptiles of assigned continent • 1. North America2. South America3. Europe4. Asia5. Africa6. Australia (Oceania) • For each reptile include the following • Order • Appearance (drawing) • Size • Diet • Habitat • Range • Status (common, rare, threatened, or endangered)