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Morphometric variation in Plio-Pleistocene hominid distal humeri
1Program in Anthropological Sciences, State University of New York at Stony Brook 11794, USA.
American Journal of Physical Anthropology
|November 1, 1996
Summary
Morphological variation in Plio-Pleistocene hominid distal humeri was analyzed by comparing fossil specimens to living hominoids. Some fossils, like KNM-ER 739 and KNM-ER 1504, show unique patterns, while others resemble chimpanzees.
Area of Science:
- Paleoanthropology
- Primatology
- Bioarchaeology
Background:
- Morphological variation in Plio-Pleistocene hominid distal humeri is debated, impacting taxonomic classification and functional interpretations.
- Previous studies show disagreement on whether observed differences warrant taxonomic separation or are within-group variation.
Purpose of the Study:
- To evaluate the magnitude and patterns of size and shape differences in fossil hominid distal humeri.
- To determine if these variations are comparable to those found within large-bodied, living hominoids.
Main Methods:
- Comparative analysis of fossil hominid distal humeri (Australopithecus, Paranthropus, early Homo) with extant hominoids (humans, chimpanzees, gorillas).
- Calculation of pairwise distances (d values) using raw measurements and scale-free shape data.
- Application of Principal Coordinate Analysis, UPGMA cluster analysis, Canonical Variates Analysis, and Discriminant Analysis.
Main Results:
- Size differences between some fossils and large extant gorillas are extreme, but shape variations for most fossils fall within extant hominoid ranges.
- Fossils KNM-ER 739 and KNM-ER 1504 exhibit unique morphometric patterns distinct from other hominid humeri.
- Non-Koobi Fora fossils generally resemble chimpanzee distal humeri in shape; Paranthropus and A. africanus specimens show distinct affinities.
Conclusions:
- The study provides a quantitative framework for assessing hominid humeral variation relative to extant hominoids.
- KNM-ER 739 and KNM-ER 1504 represent distinct morphotypes, potentially indicating unique evolutionary trajectories.
- Most other Plio-Pleistocene hominid humeri exhibit patterns consistent with variation found within extant hominoid populations, particularly chimpanzees.