Postcranial functional morphology of Morotopithecus bishopi, with implications for the evolution of modern ape locomotion
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Date
2000
Journal Title
Journal ISSN
Volume Title
Publisher
Journal of Human Evolution
Abstract
The large-bodied hominoid from Moroto, Uganda has until recently
been known only from proconsulid like craniodental remains and
some vertebrae with modern ape like features. The discovery of two
partial femora and the glenoid portion of a scapula demonstrates that
the functional anatomy of Morotopithecus differed markedly from
other early and middle Miocene hominoids. Previous studies have
consistently associated the vertebral remains with a short, stiff back
and with orthograde postures. Although the proximal femur more
closely resembles the femora of monkeys than of apes and suggests a
moderate degree of hip abduction, the distal femur resembles those of
extant large bodied apes and suggests a varied loading regime and an
arboreal repertoire that may have included substantial vertical climbing.
The femoral shaft displays uniformly thick cortical bone, beyond
the range of thickness seen in extant primates, and signifies higher
axial loading than is typical of most extant primates. The glenoid
fossa is broad and uniformly curved as in extant suspensory primates.
Overall, Morotopithecus is reconstructed as an arboreal species that
probably relied on forelimb-dominated, deliberate and vertical climbing,
suspension and quadrupedalism. Morotopithecus thus marks the
first appearance of certain aspects of the modern hominoid body plan
by at least 20 Ma. If the suspensory and orthograde adaptations
linking Morotopithecus to extant apes are synapomorphies, Morotopithecus
may be the only well-documented African Miocene hominoid
with a close relationship to living apes and humans.
Description
Keywords
Miocene, Hominoid evolution, Glenoid fossa, Femur, Vertebra
Citation
MaClatchy, L., Gebo, D., Kityo, R., & Pilbeam, D. (2000). Postcranial functional morphology of Morotopithecus bishopi, with implications for the evolution of modern ape locomotion. Journal of Human Evolution, 39(2), 159-183.