Andrewsarchus mongoliensis (Osborn 1924; middle Eocene, 45 mya; AMNH 20135; 83cm skull length) was traditionally considered a mesonychid, then an artiodactyl related to entelodonts and whales, Andrewsarchus is here recognized as a giant extinct elephant shrew, a type of leptictid, known from its skull only. Derived from a sister to Leptictis, Andrewsarchus was probably the last of its kind, based on its size. The post-crania is unknown, but based on phylogenetic bracketing. the hind limbs would have been more robust than the forelimbs.
Paratriisodon henanensis (Chow 1959; early Late Eocene) based on a partial mandible and palate was also originally considered a creodont, but here shares many traits with Andrewsarchus. |