BIOL 4141 Chapter : Eutheria Afrotheria Mammology 2014
Document Summary
Introduction: during most of the cenozoic era, eutherians dominated mammalian fauna on most continents. Mammals in south america and australia were mostly marsupials: today, 5,100 of 5,400 mammal species are placental. Cretaceous eutherians: earliest eutherian fossil is 125-million-year-old eomaia scansoria from china. Complete skeleton w/ fossilized fur: remaining record includes over 40 genera, most fossils are fragments of jaws. Difficult distinguishing eutherians and metatherians based on tooth and jaw features alone. Incisor # reduced from early (5/4) to late (3/3) Premolar # reduced from early (5/5) to late (4/4) Ancestral state for dental formula of extant eutherians: 3/3 1/1 4/4 3/3 = 44. Cretaceous eutherians: probably played a variety of ecological roles. Insectivory, carnivory, and herbivory (inferred from tooth shapes) Climbers, jumpers, diggers, and generalized runners (inferred from post-cranial skeletons) Euarchontoglires a i r e h t u e o e r o. Figure 8-1: one phylogenetic hypothesis of the evolutionary relationships among the afrotheria.
