词条 | Condylarthra |
释义 | Condylarthra mammal order ![]() Condylarths appear to have originated in Asia during the Cretaceous Period (145.5–65.5 million years ago). The earliest condylarths were the zhelestids, rodent-sized ungulates from the late Cretaceous of Uzbekistan. A somewhat later North American form is the genus Protungulatum that lived near the end of Cretaceous or early in the Paleocene. The condylarths were a diverse group that developed many traits of adaptive significance; they are thought to be the ancestors of the perissodactyls (perissodactyl) and perhaps even the cetaceans (cetacean). Some forms remained relatively small, whereas others attained large size. Phenacodus, a well-known condylarth from the Eocene Epoch (55.8–33.9 million years ago), grew to be as large as a modern tapir. In addition, the teeth of some condylarths appear almost carnivore-like (carnivore); Arctocyon, for example, has long canines and triangular premolars. |
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