Department of Anthropology, University of Massachusetts, Amherst
Thursday All day, Clinch Concourse
Hadropithecus stenognathus has been considered one of the most terrestrial extinct lemurs; it is frequently likened to the most terrestrial cercopithecoids. Its locomotor reconstruction, however, has been hampered by hind-limb bone misattributions and indeed by gaps in our knowledge of its hind-limb anatomy. Fossil discoveries at Andrahomana during the past decade have remedied some of these problems. We now know that the revised attributions of Godfrey and colleagues in 1997 are correct, suggesting that cercopithecoid likenesses have been exaggerated. However, a detailed assessment of the implications of new attributions is lacking.
Here we use Principal Component Analysis of functionally meaningful indices (measuring the mechanical advantage of various muscle groups, the mediolateral buttressing of the femoral shaft, femoral condyle proportions, etc.) to compare the femoral morphology of Hadropithecus to that of other extinct lemurs, extant lemurs and lorises, arboreal and terrestrial cercopithecoid monkeys, platyrrhines, and hominoids. Our database includes 233 individuals belonging to 8 extinct lemur species and 30 extant primate species. We show that: (1) extinct lemur femora differ fundamentally from those of extant arboreal quadrupedal lemurs or vertical clingers and leapers, undoubtedly because leaping was minimal or absent from extinct lemurs’ locomotor repertory; (2) most femoral indices situate both Archaeolemur and Hadropithecus considerably closer to gorillas than to Papio or Mandrillus; (3) Hadropithecus was a heavy and powerful quadruped; (4) climbing was likely an important component of its locomotor repertory; and (4) its femur offers little evidence that this lemur was more terrestrial than Archaeolemur.
Supported in part by a University of Massachusetts faculty research grant.