Clades3

Clades3



After the KT impact, which marks the beginning of the Cenozoic era, and the end of the age of dinosaurs, -marsupials had already been overrun by placental mammals everywhere but Australia, which had been separated from the rest of the supercontinent since the mid-Mesozoic. This allowed Australian marsupials to diversify into myriad groups, most of which are now extinct. Among these were a sort of carnivorous kangaroo, and a marsupial "lion", the true nature of which we'll probably never know. Elsewhere in the world, eutherian mammals also diverged into numerous sub-groups, all of whom of course initially looked very similar to each other early on. Before they really began to "grow apart", most of them resembled rats or shrews or opossums. Some of them changed relatively little, and eventually lead to the order, Carnivora. Others developed much thicker keratin on their claws, to the point that they had to walk on the claw itself rather than on their toes. These lead to the ungulates, which are a very diverse group, especially since it includes whales as hooved carnivores! Both of these orders are considered part one superorder, Laurasiatheria, one of four major initial divisions of placental mammals. The common bond between the hooved animals and the carnivores are the basal condylarths and the subsequent mesonychids. Both of these transitional genera are now completely extinct. But we still have some hooved animals like pigs and hippos that will eat meat on occasion, and we even have a few Asian deer which still have their fangs.
(see: musk deer, muntjac, & Chinese water deer)