Christopher A. Brochu1*, Jackson Njau2,3, Robert J. Blumenschine4, Llewellyn D. Densmore5
1 Department of Geoscience, University of Iowa, Iowa City, Iowa, United States of America, 2 Human Evolution Research Center, Department of Integrative Biology, University of California, Berkeley, California, United States of America, 3 National Natural History Museum, Arusha, Tanzania, 4Center for Human Evolutionary Studies, Department of Anthropology, Rutgers University, New Brunswick, New Jersey, United States of America, 5Department of Biological Sciences, Texas Tech University, Lubbock, Texas, United States of America
Abstract
Background
The fossil record reveals surprising crocodile diversity in the Neogene of Africa, but relationships with their living relatives and the biogeographic origins of the modern African crocodylian fauna are poorly understood. A Plio-Pleistocene crocodile from Olduvai Gorge, Tanzania, represents a new extinct species and shows that high crocodylian diversity in Africa persisted after the Miocene. It had prominent triangular “horns” over the ears and a relatively deep snout, these resemble those of the recently extinct Malagasy crocodile Voay robustus, but the new species lacks features found among osteolaemines and shares derived similarities with living species of Crocodylus.
Methodology/Principal Findings
The holotype consists of a partial skull and skeleton and was collected on the surface between two tuffs dated to approximately 1.84 million years (Ma), in the same interval near the type localities for the hominids Homo habilis and Australopithecus boisei. It was compared with previously-collected material from Olduvai Gorge referable to the same species. Phylogenetic analysis places the new form within or adjacent to crown Crocodylus.
Conclusions/Significance
The new crocodile species was the largest predator encountered by our ancestors at Olduvai Gorge, as indicated by hominid specimens preserving crocodile bite marks from these sites. The new species also reinforces the emerging view of high crocodylian diversity throughout the Neogene, and it represents one of the few extinct species referable to crown genus Crocodylus.
Citation: Brochu CA, Njau J, Blumenschine RJ, Densmore LD (2010) A New Horned Crocodile from the Plio-Pleistocene Hominid Sites at Olduvai Gorge, Tanzania. PLoS ONE 5(2): e9333. doi:10.1371/journal.pone.0009333
Editor: Carles Lalueza-Fox, Institute of Evolutionary Biology (CSIC-UPF), Spain
Received: December 9, 2009; Accepted: January 27, 2010; Published: February 24, 2010
Copyright: © 2010 Brochu et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Funding: National Science Foundation (www.nsf.gov): NSF DEB 0444133, NSF DEB 0228648. Wenner-Gren Foundation for Anthropological Research (www.wennergren.org). Rutgers University Center for Human Evolutionary Studies (evolution.rutgers.edu). National Geographic Committee for Research and Exploration (www.nationalgeographic.com/field/grants-programs/cre.html ). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing interests: The authors have declared that no competing interests exist.
* E-mail: chris-brochu@uiowa.edu
Copyright: © 2010 Brochu et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Funding: National Science Foundation (www.nsf.gov): NSF DEB 0444133, NSF DEB 0228648. Wenner-Gren Foundation for Anthropological Research (www.wennergren.org). Rutgers University Center for Human Evolutionary Studies (evolution.rutgers.edu). National Geographic Committee for Research and Exploration (www.nationalgeographic.com/field/grants-programs/cre.html ). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing interests: The authors have declared that no competing interests exist.
* E-mail: chris-brochu@uiowa.edu
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