BIOL 101 Lecture Notes - Lecture 19: Archosaur, Theria, Prototheria
Document Summary
Archosauria (crocodilians, dinosaurs, birds: mammalia (most basal, branch off first): Ancestral trait: anapsid skull: no lateral temporal opening. Mammal (synapsida): synapsid skull: one lateral temporal opening. Reptiles (diapsida): diapsid skull: dorsal and lateral openings: characteristics for living on land: Flexible (reptiles), rigid (birds), lost (most mammals, some reptiles. Amnion: fluid-filled cavity for embryo, absorbs shock, provides moist cover. No aquatic larvae: free living larvae absent. Excrete urea or uric acid: metabolic waste. Respiration by lungs: free-living stage use lungs. Testudines (turtles): unknown closest living relative, evolved 200 mya, 330 living species: inhabit various habitats, shell: Plastron: ventral, may be hinged to protect head when pulled in. Formed from fused vertebrae and ribs (still have spinal cord) Often ornate and brightly colored: lack teeth: jaw modified into a beak, oviparous (eggs laying): Embryo development can take anywhere from a month to a year. Gender determined by temperature in nest: freshwater turtles: Mata mata: leaf mimic: terrestrial turtles:
