Reptiles

Modern Reptiles

• Reptiles are classified into 16 orders, 12 that are extinct.

- 4 surviving-6, 000 species

• Reptiles occur worldwide except in coldest regions

- Human intervention-major impact

• 4 living orders of Class Reptilia:

- 1. Rhynchocephalia,

- 2. Chelonia,

- 3. Crocodilia,

- 4. Squamata

Rhynchocephalia

• Only living species- Sphenodon punctatus- the tuatara

-  Inhabit islands off coast of New Zealand

- Resembles a large lizard about 60 cm long

- Has an inconspicuous third eye on top of its head- parietal eye- functions as a thermostat- protects from overheating

- Active at low temperatures and feed at night on insects, worms and small animals

Chelonia

• Order consists of about 265 species of turtles and tortoises

- Tortoise are terrestrial Chelonia

- Turtles- chelonians that live in water

- Body covered by a shell made of hard plates- 2 parts- a carapace and plastron

- Shape is modified for variety of ecological demands

- retract heads, swimming

- Forelimbs of a marine turtle have evolved into flippers and freshwater turtles have webbed toes

- Migratory behavior of sea and river turtles

-return to land to lay eggs

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Chelonia

Crocodilia

• Order composed of 20 species of large lizard-shaped reptiles- crocodiles, alligators, caimans and gavials 
• Crocodilians live in or near water in tropical/ subtropical regions of the world
• - Crocodiles- nocturnal animals; Africa, Asia and Americas
• -  Alligators - China and southern U.S.

- Caimans- Central America- some in Florida

- Gavials- eat fish; long and slender snout- live only in Burma and India

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• Carnivorous- hunt by stealth- features adapted for this behavior

  - Eyes on head, nostrils on top of snout

-see and breathe while in water

- Valve to prevent water from entering air passage

- Parental care- both parents care for young by carrying in jaws until development

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Squamata

• Order consists of 5,640 species of lizards and snakes

- Loosely jointed upper jaw and paired reproductive organs in males

- Structurally diverse

•  -  Live everywhere except Antarctic

- Special adaptations- agility and camouflage

- Most prey on insects or small animals

Suborder Sauria

• Lizards
• Geckos
• Iguanas
• Chameleons
• Gila monster / Mexican beaded lizard

Suborder Serpentes

• Snakes