Mesonychids

Mesonyx ("middle claw") is an extinct genus of mesonychid, one of the families that is part of the extinct order Mesonychia. Fossils of the various species are found in Early to Late Eocene-age strata in the United States and Early Eocene-aged strata in China, 51.8—51.7 Ma (AEO).

Mesonychidae (meaning "middle claws") is an extinct family of small to large-sized omnivorous-carnivorous mammals. They were endemic to North America and Eurasia during the Early Paleocene to the Early Oligocene, and were the earliest group of large carnivorous mammals in Asia. Once considered a sister-taxon to artiodactyls, recent evidence now suggests no close connection to any living mammal. Mesonychid taxonomy has long been disputed and they have captured popular imagination as "wolves on hooves", animals that combine features of both ungulates and carnivores. Skulls and teeth have similar

Sinonyx ("Chinese claw") is a genus of extinct, superficially wolf-like mesonychid mammals from the late Paleocene of China (about 56 million years ago). It is within the family Mesonychidae, and cladistic analysis of a skull of Sinonyx jiashanensis identifies its closest relative as Ankalagon. S. jiashanensis was discovered in Anhui province, China (, paleocoordinates ), in the Tuijinshan formation.

Pachyaena (literally, "thick hyena") was a genus of heavily built, relatively short-legged mesonychids. Mesonychids were part of the now extinct order known as Mesonychia, a group mammalian predators that evolved before modern ungulates or carnivorans. Despite this, mesonychians are found to have combined characteristics of both carnivorans and ungulates. The genus likely originated from Asia and dispersed to Europe, and from there to North America across a land bridge in what is now the North Atlantic ocean. Pachyaena would later be replaced by Dissacus in Europe.

Harpagolestes ("hooked thief") is an extinct genus of hyena like, bear sized mesonychid mesonychian that lived in Central and Eastern Asia and western and central North America during the middle to late Eocene. It has been suggested that Harpagolestes is a wastebasket genus for fragmentary Eocene mesonychids.

Synoplotherium (synonym Dromocyon) is an extinct genus of relatively small, wolf-like mesonychids that lived 50 million years ago, in what is now Wyoming. thumb|left|Synoplotherium lanius thumb|left|Restoration by Robert Bruce Horsfall Synoplotherium coexisted with its larger relative, Mesonyx. Very little else remains known about this mesonychid since its discovery in 1875.

Ankalagon is an extinct genus of carnivorous mammal of the family Mesonychidae, endemic to North America during the Paleocene epoch (63.3—60.2 mya), existing for approximately . There is only one known species: the type species Ankalagon saurognathus. Discovered in the Nacimiento Formation of New Mexico, Ankalagon is the largest mesonychid known from the Paleocene of North America and it provides the best evidence for sexual dimorphism in the group.

Mongolonyx is an extinct genus of carnivorous mesonychid mammal that lived during the Middle Eocene in Inner Mongolia (China). It was described by Szalay and Gould.

Mongolestes ("Mongolian robber") is an extinct genus of mesonychid known from the 'Ulan Gochu' formation of Inner Mongolia, and likely originated in Asia. It was the last surviving representative of Mesonychia and became extinct in the early Oligocene.

Dissacus is a genus of extinct carnivorous jackal to coyote-sized mammals within the family Mesonychidae, an early group of hoofed mammals that evolved into hunters and omnivores. Their fossils in Paleocene to Early Eocene aged strata in France, Asia and southwest North America, from 66 to 50.3 mya, existed for approximately .

genus of mammals

Yantanglestes is a genus of small, Chinese mesonychid with slender jaws that first appeared during the Early Paleocene in the Thanetian stage. It was found throughout Asia. It is the oldest known mesonychid. Yantanglestes became extinct during the Nongshanian division of the Late Paleocene, and lived sympatrically with its descendant genera, including Dissacus, Sinonyx and Jiangxia.