Middle Pliocene hominin diversity: Australopithecus deyiremeda and Kenyanthropus platyops.
Geometric morphometric shape analyses are used to compare the maxillae of the Kenyanthropus platyops holotype KNM-WT 40000, the Australopithecus deyiremeda holotype BRT-VP-3/1 and other australopiths. The main aim is to explore the relationship between these two specimens and contemporary Australopithecus afarensis Five landmarks placed on lateral views of the maxillae quantify key aspects of the morphology. Generalized Procrustes analyses and principal component analyses of the resulting shape coordinates were performed. The magnitudes of differences in shape and their significances were assessed using Procrustes and Mahalanobis' distances, respectively. Both KNM-WT 40000 and BRT-VP-3/1 show statistically significant differences in maxillary shape from A. afarensis, but do so in dissimilar ways. Moreover, the former differs more from A. afarensis than the latter. KNM-WT 40000 has a more anteriorly positioned zygomatic process with a transversely flat, and more orthognathic subnasal clivus. BRT-VP-3/1 has a more inferiorly positioned zygomatic process, a slightly retracted dental arcade, but without shortening of the anterior maxilla. These findings are consistent with previous conclusions that the two fossils should be attributed to separate species, rather than to A. afarensis, and with the presence of three contemporary hominin species in the Middle Pliocene of eastern Africa.This article is part of the themed issue 'Major transitions in human evolution'.
Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig 04103, Germany f.spoor@eva.mpg.de.
Fred
F
Spoor
Turkana Basin Institute, PO Box 24926, Nairobi 00502, Kenya Department of Anthropology, Stony Brook University, Stony Brook, NY 11794, USA.
Meave G
MG
Leakey
Centre for Anatomical and Human Sciences, Department of Archaeology and Hull York Medical School, University of York, York YO10 5DD, UK.
Paul
P
O'Higgins
D000351:Africa, Eastern; D000818:Animals; D044822:Biodiversity; D005075:Biological Evolution; D005145:Face / Q000033:anatomy & histology; D005580:Fossils / Q000033:anatomy & histology*; D015186:Hominidae / Q000033:anatomy & histology*
Africa; Pliocene; geometric morphometrics; hominin evolution; maxilla; species diversity