Entelodontidae

Entelodontidae is an extinct family of pig-like artiodactyls (even-toed ungulates) which inhabited the Northern Hemisphere (Asia, Europe, and North America) from the late Eocene to the Middle Miocene epochs, about 38-19 million years ago. Their large heads, low snouts, narrow gait, and proposed omnivorous diet inspires comparisons to suids (true pigs) and tayassuids (peccaries), and historically they have been considered closely related to these families purely on a morphological basis. However, studies which combine morphological and molecular (genetic) data on artiodactyls instead suggest that entelodonts are cetancodontamorphs, more closely related to hippos and cetaceans through their resemblance to Pakicetus, than to basal pigs like Kubanochoerus and other ungulates. Entelodonts could get quite large, and in many cases are the largest mammals in their respective ecosystems. The largest entelodont known from a complete skeleton was Daeodon, a North American entelodont which could reach an estimated weight of 750 kg (1650 pounds), and a height up to tall at the shoulder. Paraentelodon intermedium, a Eurasian species known mostly by the teeth and jaws, was similar in size to Daeodon. Entelodonts had huge heads, ornamented with distinctive bony expansions. The zygomatic arches (cheekbones) develop huge jugal flanges which project downwards and outwards. Moreover, the underside of the lower jaw typically has one or two pairs of knob-like mandibular tubercles. These are not always diagnostic to specific taxa: often the size and presence of tubercles is variable within a single species. The snout was narrow and elongated, especially in later species. The cranium was robust, with strong zygomatic and postorbital arches forming the rim of voluminous temporal fossae, separated by a sharp sagittal crest. However, the rear of the skull was also much shorter than the snout, and the braincase was relatively small. Most of the braincase contributed to large paranasal sinuses and olfactory bulbs at the front, while the cerebrum was underdeveloped.