BIOL-3030 Lecture Notes - Lecture 17: Gila Monster, Ciliary Muscle, Alethinophidia
Document Summary
Lecture 17 - reptile diversity part two - lepidosaurs and archosaurs. Living species: about 3315 snakes + 5460 other lizards. First fossils from jurassic (snakes from cretaceous) Tuatara - two living species in genus sphenodon) Squamata - has about 9000 species or so (lizards and snakes) In lepidosaurs perpendicular to long axis of the tail. External exit parallel to long axis of tail in salamander. Scaly skin impermeable to water, shed in sheets. Many species have reduced or entirely lost their limbs. Historically diverse, only two living species today. Unique dentition, second row upper teeth on palatine bone. Adults can reach 60cm, live 50+ years (large) Reproduction : females mate every 4 years. Serpentes (=snakes) and amphisbaenia origin within scleroglossa. Some limbless groups are important to know - snakes. Determinate growth - they do reach maximum adult size(stop growing) They don"t have to find a mate - greater output of eggs.
