Cranial shape variation in Homo erectus

by Baab, Karen L., Ph.D., CITY UNIVERSITY OF NEW YORK, 2007, 511 pages; 3283157

Abstract:

The fossil hominin species Homo erectus spanned nearly the entire Pleistocene epoch and is known from sites in East Africa, South Africa, Georgia, China and Java. H. erectus represents the oldest occurrences of hominins outside of Africa and is associated with novel technological and behavioral adaptations.

I addressed several unanswered questions pertaining to the taxonomy and evolutionary history of H. erectus using 3D geometric morphometric techniques. Despite the relatively extensive temporal and geographic range of H. erectus, the relative degree of cranial shape variation in this taxon did not exceed that seen in several subspecies and species of non-human primates, and was comparable to the variation seen in a recent, geographically disperse H. sapiens sample. This observation was most comparable with a single species interpretation for H. erectus . A combination of primitive (e.g., a low midline cranial profile), derived (e.g., relatively wide anterior vault), and unique (e.g., the great width of the occipital bone) shape features served to diagnose H. erectus relative to H. habilis, mid-Pleistocene Homo, Neanderthals and H. sapiens. The affinities of several newly described fossils were assessed against this definition. For example, the Dmanisi hominins fit well within the range of variation expressed by other H. erectus individuals, while ER 42700 from Ileret did not. While there was a strong intraspecific geographic signal within H. erectus, cranial shape also changed over time within more limited regions of the Old World. The Asian populations of H. erectus were autapomorphic in certain aspects of their cranial shape (e.g., the occipital bone) relative to later Homo species, and were most likely an evolutionary dead end. There appears to have been greater variation within the earlier populations of Indonesian hominins from Sangiran than in later Javanese populations.

This dissertation also described patterns of cranial shape evolution along several proposed phylogenetic trees for the genus Homo, highlighting a general increase in cranial height and breadth and a decrease in constriction across frontotemporale, changes likely related to increases in brain size. By examining the relationship between cranial shape and size, it was demonstrated that the cranial shape of Liang Bua 1 (LB1) is comparable to a scaled down H. erectus individual.

AdviserEric Delson
SchoolCITY UNIVERSITY OF NEW YORK
Source TypeDissertation
SubjectsPhysical anthropology
Publication Number3283157

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