Pachyaena

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.

== Taxonomy == thumb|525x525px|Cladogram showing the position of the Mesonychia The genus' greatest diversity is seen in North America, with P. ossifraga known from Latest Paleocene strata of Wyoming, and P. gigantea, P. intermedia, and P. gracilis known from Early Eocene strata of Wyoming. P. nemegetica is known from Late Paleocene strata of Mongolia. However, a 2007 paper suggests that Pachyaena may be paraphyletic, with P. ossifraga being closer to Synoplotherium, Harpagolestes and Mesonyx than to P. gigantea.