The Pliocene hominin diversity conundrum: Do more fossils mean less clarity?
Yohannes Haile-Selassie a,b,1, Stephanie M. Melillo c, and Denise F. Su d
aDepartment of Physical Anthropology, Cleveland Museum of Natural History, Cleveland, OH 44106;
bDepartments of Anthropology, Anatomy, and Cognitive Sciences, Case Western Reserve University, Cleveland, OH 44106;
cDepartment of Human Evolution, Max Planck Institute for Evolutionary Anthropology, D-04103 Leipzig, Germany;
dDepartment of Paleobotany and Paleoecology, Cleveland Museum of Natural History, Cleveland, OH 44106
Edited by Richard G. Klein, Stanford University, Stanford, CA, and approved January 7, 2016 (received for review November 6, 2015)
Recent discoveries of multiple middle Pliocene hominins have raised the possibility that early hominins were as speciose as later hominins. However, debates continue to arise around the validity of most of these new taxa, largely based on poor preservation of holotype specimens, small sample size, or the lack of evidence for ecological diversity. A closer look at the currently available fossil evidence from Ethiopia, Kenya, and Chad indicate that Australopithecus afarensis was not the only hominin species during the middle Pliocene, and that there were other species clearly distinguishable from it by their locomotor adaptation and diet. Although there is no doubt that the presence of multiple species during the middle Pliocene opens new windows into our evolutionary past, it also complicates our understanding of early hominin taxonomy and phylogenetic relationships.
hominin diversity Australopithecus Kenyanthropus Pliocene ecological diversity
1To whom correspondence should be addressed. Email: firstname.lastname@example.org.
Author contributions: Y.H.-S. designed research; Y.H.-S., S.M.M., and D.F.S. performed research; Y.H.-S., S.M.M., and D.F.S. analyzed data; and Y.H.-S., S.M.M., and D.F.S. wrote the paper.
The authors declare no conflict of interest.
This article is a PNAS Direct Submission.
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