title: No brain expansion in Australopithecus boisei.
abstract: The endocranial volumes of robust australopithecine fossils appear to have increased in size over time. Most evidence with temporal resolution is concentrated in East African Australopithecus boisei. Including the KNM-WT 17000 cranium, this sample comprises 11 endocranial volume estimates ranging in date from 2.5 million to 1.4 million years ago. But the sample presents several difficulties to a test of trend, including substantial estimation error for some specimens and an unusually low variance. This study reevaluates the evidence, using randomization methods and a related test using an explicit model of variability. None of these tests applied to the A. boisei endocranial volume sample produces significant evidence for a trend in that species, whether or not the early KNM-WT 17000 specimen is included.
authors.affiliation: Department of Anthropology, University of Wisconsin-Madison, Madison, WI 53706-1393, USA. jhawks@wisc.edu
authors.forename: John
authors.initials: J
authors.lastname: Hawks
mesh_terms: D000818:Animals; D005075:Biological Evolution; D001921:Brain / Q000033:anatomy & histology*; D005260:Female; D005580:Fossils; D015186:Hominidae / Q000033:anatomy & histology*; D016014:Linear Models; D008297:Male; D008954:Models, Biological; D012886:Skull / Q000033:anatomy & histology*