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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. Some Early Reptilians. General Reptile Traits. Reproduction
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Traditional Taxonomy • Class Reptilia • Order Testudines – turtles, terrapins, tortoises • Order Crocodilia – crocs & gators • Order Squamata – snakes & lizards • Order Sphenodonta – tuatara
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)
Sex Determination in Turtles & Crocodilians • Turtles • Males develop at low temps • Females develop at higher temps • Crocodilians • Males develop at higher temps • Females develop at lower temps
Order Squamata • Shed their epidermal scales with growth
Snake Families • Viperidae • 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 mouthor water moccasin Copper head Rattlesnake Viperidae
Snake Venoms • Neurotoxins • Paralysis • Blindness • Hemorrhagins • Digest tissues • Prevent clotting Fasciotomy
Pit Organs of Pit Vipers Family Viperidae Subfamily Crotalidae
Red on yellow, kill a fellow Red on black, friend to jack Coral snake or King snake
Temperature Regulation • Cold-blooded vs warm-blooded • Poikilothermy vs homeothermy • Ectothermy vs Endothermy