Class Reptilia

Turtles, Tortoises, Tuataras, Crocodilians, Lizards, and Snakes

Classification

• Domain Eukarya• Kingdom Animalia• Phylum Chordata– Subphylum Vertebrata

• Class Reptilia– Order Chelonia– Order Crocodilia– Order Squamata– Order Rhynchocephalia

Order Chelonia• Turtles and Tortoises– Earliest fossils dated to 200 m.y.a– Shell consists of fused boney plates• Carapace (Dorsal, top)• Plastron (Ventral, lower)

– 250 species worldwide– Variety of habitats

• Most species ribs and spine fused to inner surface of carapace

• Pelvic and Pectoral girdles lie within the ribs

• Sharp beak instead of teeth

• Shell and limbs reflect habitat

Turtles• Marine or freshwater• Stream – lined shells• Webbing between toes• Terrapin refers to small aquatic or semi –

aquatic other than sea turtles

Tortoises• Heavy domed shell• Retract limbs and head• Limbs sturdy with scales• Clubbed walking feet

Order Crocodilia• Crocodiles, Alligators, Caimans, Gavial

Order Crocodilia

• Most closely related to dinosaurs• Heavy bodied, mostly aquatic• Carnivorous

Order Squamata

• Lizards and Snakes– Upper jaw is loosely joined to the skull– Jacobson’s organ

Lizards• Only 2 species venomous– Gila Monster– Bearded Lizard

• Autotomy

Snakes• Backbone of 100 – 400 vertebrates– Pair of ribs attached to each vertebra

• Seize and swallow prey• Constrictors• Venom– Fangs back of mouth– Elapid, inject poison through fixed fangs in front– Vipers, inject venom using large mobile fangs

Order Rhynchocephalia• Ancient order inhabit few

small islands of New Zealand

• 24 inches in length• Spiny crest that runs down

the animal’s back• Tolerate cool temp,

burrow during day and hunt at night