BIO 370 Vertebrate Zoology
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Vertebrate Diversity
Class Reptilia Reptiles

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Amniote Characteristics

  • Amniotic egg
  • Keratinized, waterproof epidermis
  • Claws and other elaborations of epidermis
  • Costal lung ventilation
  • Heart has partially or completely divided ventricle
  • Specialized axis (2nd vertebra)

Reptilia Characteristics

  • Ectothermy
  • Skin typically covered in scales
  • Typically move by lateral undulations of body
  • Heart 3-chambered or with ability to bypass lungs
  • Taxonomic note: Reptilia (as used here) is a paraphyletic group
See also
Reptile Anatomy page

Order Testudines Turtles

    • Anapsid skull with posterior emarginations
    • Shell formed from pectoral girdle, ribs, dermal plates
    • No teeth: mouth forms horny beak
Pond Slider
Pond Slider, Trachemys scripta (Family Emydidae); a typical semiaquatic pond turtle
Desert Tortoise
Desert Tortoise, Gopherus agassizii (Family Testudinidae), CA; a fully terrestrial tortoise
Box Turtle
Eastern Box Turtle, Terrapene carolina (Family Emydidae), KY; a terrestrial tortoise-like turtle
Snake-necked Turtle
Common Snake-necked Turtle, Chelodina longicollis (Family Chelidae); an aquatic sit-and-wait predator (strike and gape feeding)
Alligator Snapping Turtle
Alligator Snapping Turtle, Macroclemys temminckii (Family Chelydridae); an aquatic sit-and-wait predator (cryptic suction feeder; note pink worm-like tongue)
Mata Mata, Chelus fimbriatus (Family Chelidae); an aquatic sit-and-wait predator (cryptic suction feeder)
Spiny Softshell
Spiny Softshell, Trionyx spiniferus (Family Trionychidae); an active chaser
Fly River Turtle
Fly River Turtle, Carettochelys insculpta (Family Carettochelyidae); the only fully aquatic fresh-water turtle
Loggerhead Turtle
Loggerhead Sea Turtle, Caretta caretta (Family Cheloniidae); a fully aquatic marine turtle

Order Rhynchocephalia Tuataras

    • Generalized lizard-like body
    • Relatively large-sized
    • Nocturnal
    • Skull not kinetic
    • Two temporal fenestra; lower temporal bar
    • Sometimes placed in Order Sphenodontia
Tuatara Skull
Spotted Tuatara skull, Sphenodon punctatus
See also labeled photo.
Tuatara Drawing
Spotted Tuatara, Sphenodon punctatus
Source: R. A. Lydekker 1896. The Royal Natural History, London. Retrieved from Wikimedia

Order Squamata Lizards, Snakes, etc.

    • Generalized tetrapod body plan with sprawling limbs
    • Loss of limbs evolved numerous times
    • Mostly predatory
    • Males have hemi-penes (paired penis)
    • Loss of lower temporal bar
    • Increasing skull kinesis


  • Paraphyletic: includes all squamates except snakes and amphisbaenians.
  • Most have limbs, but leglessness evolved several times
  • Most have eyelids, external ear openings
  • See also Lizard Skulls page
Medit. House Gecko
Mediterranean House Gecko, Hemidactylus turcicus (Family Gekkonidae), AZ; specialized climber on smooth surfaces
Montane Side-striped Chameleon, Trioceros ellioti (Family Chamaeleonidae), Kenya; specialized climber on narrow branches
Blue-headed Tree Agama
Blue-headed Tree Agama, Acanthocerus atricollis (Family Agamidae), Kenya; a generalized ambush predator
Side-blotched Lizard
Common Side-blotched Lizard, Uta stansburiana (Family Phrynosomatidae); UT; a generalized ambush insectivore
Desert Grassland Whiptail
Desert Grassland Whiptail, Aspidoscelis uniparens (Family Teiidae), AZ; an active-searching insectivore
Nile Monitor
Nile Monitor, Varanus niloticus (Family Varanidae), Kenya; an active-searching predator
Common Chuckwalla, Sauromalus obesus (Family Iguanidae), CA; herbivorous
Regal Horned Lizard
Regal Horned Lizard, Phrynosoma solare (Family Phrynosomatidae), AZ; an ant specialist
Gila Monster
Gila Monster, Heloderma suspectum (Family Helodermatidae); venomous; specialist nest raider
Western Skink
Western Skink, Plestiodon skiltoniatus, CA (Family Scincidae); semi-fossorial in leaf litter
Grass Lizard
Highland Grass Lizard, Chamaesaura anguina (Family Cordylidae), Kenya; lives in dense grass
Forest Limbless Skink
Western Forest Limbless Skink, Feylinia currori (Family Scincidae), Kenya; fossorial

Serpentes (Snakes)

  • Monophyletic
  • Legless, elongate
  • No moveable eyelids
  • No external ear openings
  • Forked tongue
  • See also Snake Skulls page
Lineolate Blind Snake
Lineolate Blind Snake, Typhlops lineolatus (Family Typhlopidae), Kenya; a primitive burrowing snake
Emerald Tree Boa
Emerald Tree Boa, Corallus caninus (Family Boidae); a primitive arboreal snake
Common Kingsnake
Common Kingsnake, Lampropeltis getulus (Family Colubridae), CA; specialist snake-hunter
Green Mamba
Green Mamba, Dendroaspis angusticeps (Family Elapidae); active searcher
King Cobra
King Cobra, Ophiophagus hannah (Family Elapidae); venomous, front-fanged
Rhinohorned Viper
Rhinoceros-horned Viper, Bitis nasicornis (Family Viperidae), Kenya; a venomous sit-and-wait predator


  • Legless or with only forelegs
  • Heavy rigid skull with nipping front teeth
  • Skin forms rings
  • Burrowers
Mole Lizard
Mole Lizard, Bipes biporus

Order Crocodylia Alligators & Crocodiles

    • Large size; semiaquatic
    • Heavy laterally-compressed tail
    • Elevated nostrils
    • Skin with dermal bony armor
Nile Crocodile
Nile Crocodile, Crocodylus niloticus; Kenya
American Alligator, Alligator mississippiensis; FL
Indian Gharials, Gavialis gangeticus
Freshwater Crocodile
Freshwater Crocodile, Crocodylus johnstoni
Dwarf Crocodile
Dwarf Crocodile, Osteolaemus tetraspis
False Gharial
False Gharial, Tomistoma schlegelii
This page last updated 24 July 2015 by Udo M. Savalli ()
Images and text Udo M. Savalli. All rights reserved.