Data from: A 3D geometric morphometric analysis of the bovid distal humerus, with special reference to Rusingoryx atopocranion (Pleistocene, Eastern Africa)

The family Bovidae [Mammalia: Artiodactyla] is speciose and has extant
representatives on every continent, forming key components of mammal
communities. For these reasons, bovids are ideal candidates for studies of
ecomorphology. In particular, the morphology of the bovid humerus has been
identified as highly related to functional variables such as body mass and
habitat. This study investigates the functional morphology of the bovid
distal humerus in isolation due to its increased likelihood of
preservation in the fossil record, and the resulting opportunity for
better understanding the ecomorphology of extinct bovids. A landmark
scheme of 30 landmarks was used to capture the 3D distal humerus
morphology in 111 extant bovid specimens. We find that the distal humerus
has identifiable morphologies associated with body mass, habitat
preference, and tribe affiliation, and that some characteristics are
shared between high body mass bovids and those living on hard, flat
terrain which is likely due to the high stress on the bone in both cases.
We directly apply our findings regarding extant bovids to the extinct
alcelaphine bovid, Rusingoryx atopocranion from the mid to late
Pleistocene (>33-45 ka) Lake Victoria region of Kenya. This species
is known for some peculiar morphologies including a domed cranium with
hollow nasal crests, and having small hooves for a bovid of its size.
Another interesting aspect of Rusingoryx’s skeletal morphology which has
not been addressed is an unusual protrusion on the lateral epicondyle of
the distal humerus. Despite considerable individual variation in the
Rusingoryx specimens, we find evidence to support its historical
assignment to the tribe Alcelaphini, and that it likely preferred open
grassland habitats, which is consistent with independent reconstructions
of the paleoenvironment. We also provide the most accurate body mass
estimate for Rusingoryx to date, based on distal humerus centroid size.
Overall, we are able to conclude that the distal humerus in extant bovids
is highly informative regarding body mass, habitat preference and tribe,
and that this can be applied directly to a fossil taxon with promising
results.