BIOL 4141 Chapter : Mammalian Orgins Mammology 2014

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15 Mar 2019
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Subclasses prototheria (monotremes) and theria (all other living mammals) Single opening in the temporal region of skull (temporal fenestra) Arose in the late paleozoic, ~320 mya. Common land vertebrates for 40 my until end of. Some species were large (~3 meters), but most were dog sized. Therapsida: a clade including all mammals and many mammal-like lineages. Reduction of temporal shield (enlarged fenestra) in early therapsids. Sagittal crest and zygomatic arches (in later non-cynodont therapsids) Therapsid: lots of caniniform teeth single large canine tooth, large postdentary bones, smaller postdentary bones in jaw. Therapsid: femoral head terminal, femoral head inflected medially. Cynodontia: a clade including all mammals and some mammal-like lineages. Hydrogen sulfide: 70% of terrestrial vertebrates extinct. Terrestrial environments are a clean slate during early triassic. But small therapsids and cynodonts still present. Mammalia: the clade that includes all mammals, living and extinct. Co-existed with non-mammalian therapsids (including cynodonts) during the mesozoic. Dinosaurs are the common herbivores and carnivores.

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