Class Reptilia

Traditional Taxonomy Class Reptilia Order Testudines – turtles, terrapins, tortoises Order Crocodilia – crocs & gators Order Squamata – snakes & lizards Order Sphenodonta – tuatara

Fig. 26.1 Fig. 26.1

Fig. 26.2

Some Early Reptilians Fig. 26.p547a

General Reptile Traits Reproduction Amniotic eggs with shell Internal fertilization Oviparous, ovoviviparous, viviparous (few) Direct development Epidermal scales & claws 5 digits on each limb Thoracic ribs (except turtles)

Shelled Egg Fig. 26.4

Epidermal Scales Fig. 26.3

Order Testudines Fig. 26.6

Fig. 26.8

Sex Determination in Turtles & Crocodilians Males develop at low temps Females develop at higher temps Crocodilians Males develop at higher temps Females develop at lower temps

Order Crocodilia Fig. 26.5

Crocodilians

Order Squamata Shed their epidermal scales with growth

Gekkos Fig. 26.12

Chameleons Fig. 26.13

Iguanas Fig. 26.14

Snake Families Viperidae Elapidae Colubridae Hydrophiidae Boidae Vipers Sheathed fangs at front of mouth Elapidae Short, immovable fangs at front of mouth Colubridae Rear fanged (or no fangs) Mostly non-poisonous Hydrophiidae Sea snakes Extremely poisonous Boidae Constrictors Many retain vestigial pelvic structures

Order Squamata, Suborder Serpentes Cotton mouth or water moccasin Copper head Rattlesnake Fig. 26.19 Viperidae

Snake Venoms Neurotoxins Hemorrhagins Paralysis Blindness Digest tissues Prevent clotting Fasciotomy

Viperidae Fig. 26.25

Pit Organs of Pit Vipers Family Viperidae Subfamily Crotalidae Fig. 26.24

Red on yellow, kill a fellow Red on black, friend to jack Coral snake or King snake

Elapids

Temperature Regulation Cold-blooded vs warm-blooded Poikilothermy vs homeothermy Ectothermy vs Endothermy