Andrewsarchus Question

[Papi-Anon]

I understand that recent analysis places Andrewsarchus in the same group as whales, hippos, and entelodonts. However, something about old Andy seems nothing like those groups (to me, anyways): the eye sockets.

Despite their low and wide placement, they don't really resemble any skulls of the early whale, hippo, or even entelodont ancestors, but rather they seem more like exaggerated versions of creodonts' and with their shape. Whale ancestor eye sockets seem fully or mostly encasing with the eyes and even entelodonts and hippos show distinctive similarities with their eyes. Even more, the placement of Andrewsarchus's sockets are lower on the sides of the skull in the cheek bones like the creodonts and other similar groups while the rest of the whale/hippo/entelodont relations have their eyes anatomically higher on the skull.

Has anyone else noticed this peculiarity?

[Yutyrannus]

Since you mentioned the similarity to creodonts, I just think I need to point out that creodonts are an unnatural group. The two families (Oxyaenidae and Hyaenodontidae) are more closely related to other groups than they are to each other. Therefore any shared feature between those two groups is something that evolved convergently and it could therefore have been convergent evolution that Andrewsarchus has them.

[BlueKrono]

Yes, I think the head shape is just a case of convergent evolution due to similar biological niches between the creodonts and the entelodontian Andrewsarchus, just like the modern-day gharial and the unrelated Champsosaurus. In mammals one of the best ways to determine relationships is by dentition, and that is why Andrewsarchus's classification was revised to what it is. In fact, if they had just discovered Andy's teeth without any skull they would have classified it as an entelodont right off the bat.