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
Characteristics
- Anaspid skull with posterior emarginations
- Shell formed from pectoral girdle, ribs, dermal plates
- No teeth: mouth forms horny beak
|
Pond Slider, Trachemys scripta; a pond turtle
|
Snapping Turtle, Chelydra serpentina, KY; a stationary bottom-dweller
|
Spiny Softshell, Trionyx spiniferus; an active chaser
|
Desert Tortoise, Gopherus agassizii, CA; a fully terrestrial tortoise
|
Loggerhead Sea Turtle, Caretta caretta; a fully aquatic turtle
|
|
|
Order Rhynchocephalia — Tuataras
Characteristics
- Generalized lizard-like body
- Relatively large-sized
- Nocturnal
- Skull not kinetic
- two temporal fenestra; lower temporal bar
|
Spotted Tuatara skull, Sphenodon punctatus
See also labeled photo.
|
Spotted Tuatara, Sphenodon punctatus
Source: R. A. Lydekker 1896. The Royal Natural History, London. Retrieved from Wikimedia
|
|
Order Squamata — Lizards, Snakes, etc.
Characteristics
- Generalized tetrapod body plan
- Loss of limbs evolved numerous times
- Mostly predatory
- Males have hemi-penes (paired penis)
- Loss of lower temporal bar
- Increasing skull kinesis
|
"Lizards"
- 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
|
Common Side-blotched Lizard, Uta stansburiana; UT; a generalized ambush insectivore
|
Blue-headed Tree Agama, Acanthocerus atricollis, Kenya; a generalized ambush predator
|
Desert Grassland Whiptail, Aspidoscelis uniparens, AZ; an active-searching insectivore
|
Nile Monitor, Varanus niloticus, Kenya; an active-searching predator
|
Regal Horned Lizard, Phrynosoma solare, AZ; an ant specialist
|
Common Chuckwalla, Sauromalus obesus, CA; herbivorous
|
Tropical House Gecko, Hemidactylus mabouia, Kenya; specialized climber on smooth surfaces
|
Montane Side-striped Chamaeleon, Chamaeleo ellioti, Kenya; specialized climber on narrow branches
|
Gila Monster, Heloderma suspectum; venomous; raids nests and burrows
|
Highland Grass Lizard, Chamaesaura anguina, Kenya; lives in dense grass
|
Western Forest Limbless Skink, Feylinia currori, Kenya; fossorial
|
Serpentes (Snakes)
- Monophyletic
- Legless, elongate
- No moveable eyelids
- No external ear openings
- Forked tongue
- See also Snake Skulls page
|
Lineolate Blind Snake, Typhlops lineolatus, Kenya; a primitive burrowing snake
|
Emerald Tree Boa, Corallus caninus; a primitive snake (Boidae)
|
California Coachwhip, Masticophis lateralis, CA; active searcher (Colubridae)
|
Rhinoceros-horned Viper, Bitis nasicornis, Kenya; a sit-and-wait predator (Viperidae)
|
King Cobra, Ophiophagus hannah; (Elapidae)
|
Amphisbaenia
- Legless or with only forelegs
- Heavy rigid skull with nipping front teeth
- Skin forms rings
- Burrowers
|
Mole Lizard, Bipes biporus
|
|
Order Crocodylia — Alligators & Crocodiles
Characteristics
- Large size; semiaquatic
- Heavy laterally-compressed tail
- Elevated nostrils
- Skin with dermal bony armor
|
Nile Crocodile, Crocodylus niloticus; Kenya
|
American Alligator, Alligator mississippiensis; FL
|
Indian Gavial, Gavialis gangeticus
|
|
|
|
