Reptile Basics

What makes a reptile a reptile?

• scales, not fur

• have dry skin

• usually lay eggs, sometimes live young

• ear holes instead of ears

• 4 legs or no legs

• cold-blooded

Evolution

• Amniotes= reptiles, birds, and mammals—adaptations to living on land

  • amniotic egg with extraembryonic membranes

  • less permeable skin

  • more upright stance

• Sauropsida = reptiles and birds

  • anapsids

  • diapsids

  • 

• Synapsida—mammals

Classification

• Class reptilia

  • Order Testudines = turtles

  • Order Crocodylia= alligators and crocodiles

  • Order Squamata= snakes and lizards

  • Order Tuatara= living fossil/living dinosaur, only one in New Zealand, only 1 species

Order Testudines = Turtles

• Boxlike shell with upper and lower sheilds attached to the ribs

  • dorsal shell=carapace

  • ventral shell= plastron

• Carapace is fusion of vertebrae and ribs with dermal bones

• Shell covered with scutes

• long lived—some live > 100 years

• no teeth

• sharp beak, tomium

• most are omnivores

Order Crocodylia = alligators and crocodiles

• large, semi-aquatic

• body hasn’t changed in 75 million years

• long, flattened snout

• strong, laterally compressed tail

• carnivorous

Order Squamata = lizards and snakes

• largest order > 6000 species

• periodically shed skin

• very diverse— size, diet, habitat, reproduction

What’s the only species in the world whose scientific name is exactly the same as its common name?

• Boa constrictor