Anthracotheriids, with extant and fossil hippopotamids, make up the Hippopotamoidea superfamily. This clade is interpreted from a molecular standpoint as the sister-group of Cetacea. This hypothesis is discussed in paleontology, notably in the search for the common ancestor of Cetancodonta and of the transitional forms between this ancestor and the first archeocetes.
Multiple problematics arise from this context :
Is there a phylogenetic signal in the postcranial skeleton of Cetartiodactyla
What does the skeleton of the common ancestor of Hippopotamoids look like ?
How did an adaptation to a semi-aquatic lifestyle impact the postcranial morphology of this clade ?
To answer these question, I am analyzing osteological material from extant and extinct Hippopotamoids. I am also studying discrete anatomical traits on each bone as well as different dimensions, ratios or proxies to build and reinforce a phylogeny of Hippopotamoidea.
I am also considering different morphofunctional aspects on these structures to ientify different adaptative traits linked to immersion during the last 40 million years of the evolutionary history of this group.