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