extinct human species, including the holotypes of Australopithecus boisei and Homo habilis, as well as evidence of the earliest stone tools [33,34,35]. Some of these hominids were bitten by crocodiles at or near the time of death [36,37], and some objects thought to be early tools may be crocodile gastroliths [38]. The crocodiles were referred first to C. niloticus [39] and later to Rimasuchus lloydi [2]. A partial skull and skeleton collected in 2007 by the Olduvai Landscape Paleoanthropology Project prompted a reevaluation of crocodile remains from Olduvai Gorge. It reveals a deep-snouted, horned animal outwardly similar to a recently-extinct osteolae- mine from Madagascar (Voay robustus) but referable to Crocodylus. It can be distinguished from other known species of Crocodylus, living or extinct, and forms the basis for a new species. Institutional Abbreviations AMNH, American Museum of Natural History, New York; FMNH, Field Museum, Chicago; KNM, National Museums of Kenya, Nairobi; NHM, Natural History Museum, London; NNHM-OLD, National Natural History Museum, Arusha, Tanzania (Olduvai Collections); PNCZ, Parque Nacional Cie´naga de Zapata, Playa Larga, Matanzas, Cuba; USNM, U.S. National Museum of Natural History, Washington, DC. Anatomical Abbreviations 4t, 4th trochanter of femur; an, angular; art, articular; asf, anterior sacral facet; bo, basioccipital; ccr, caviconchal recess; cor, coronoid; cqc, cranioquadrate canal; cr, recesses on caviconchal recess medial wall; d, dentary; dlc, deltoid crest; dp, diapophysis; dpc, deltopectoral crest; ect, ectopterygoid; emf, external mandib- ular fenestra; en, external naris; eoa, external otic aperture; ex, exoccipital; f, frontal; faa, articular foramen aereum; faq, quadrate foramen aereum; fioc, foramen intermedius oralis caudalis; fm, foramen magnum; gf, glenoid fossa of articular; gfs, scapular glenoid fossa; hyp, hypapophysis; ibc, constriction on psterior iliac blade; if, incisive foramen; itf, infratemporal fenestra; j, jugal; k, keel; l, lacrimal; lc, lacrimal crest; lcf, lateral carotid foramen; leu, lateral Eustachian foramen; lf, lingual foramen; lhc, lateral hemicondyle; lp, lateral lamina of articular on surangular; m.pfp, medial process, prefrontal pillar; m5, fifth maxillary tooth/alveolus; mg, Meckelian groove; mhc, quadrate medial hemicondyle; mjf, medial jugal foramen; msc, muscle attachment scar; mx, maxilla; n, nasal; o, orbit; oc, occipital condyle; op, odontoid process; p.m5, protuberance on dorsal surface of maxilla corresponding to 5th alveolus; pal, palatine; pf, prefrontal; pfp, prefrontal pillar; pmx, premaxilla; pnr, prenarial rostrum; po, postorbital; pob, postorbital bar; poz, postzygapophysis; prz, prezygapophysis; psf, preotic siphonial foramen; psf, posterior sacral facet; pt, pterygoid; q, quadrate; qj, quadratojugal; sa, surangular; soc, supraoccipital; sof, suborbital fenestra; sp, splenial; sq, squamosal; stf, supratemporal fenestra; sym, symphysis; ta, posteriormost (terminal) alveolus; tp, transition point between dorsal surface of skull table and squamosal horn; vf, vagus foramen; xii, foramen for hypoglossal nerve (cranial nerve 12). Articulation surfaces for adjacent bone denoted with ‘‘s.’’ (e.g. articulation surface for the maxilla = s.mx). Nomenclatural Acts The electronic version of this document does not represent a published work according to the International Code of Zoological Nomenclature (ICZN), and hence the nomenclatural acts contained in the electronic version are not available under that Code from the electronic edition. Therefore, a separate edition of this document was produced by a method that assures numerous identical and durable copies, and those copies were simultaneously Extinct Horned Crocodile obtainable (from the publication date noted on the first page of this article) for the purpose of providing a public and permanent scientific record, in accordance with Article 8.1 of the Code. The separate print-only edition is available on request from PloS by ending a request to PloS ONE, 185 Berry Street, Suite 3100, San Francisco, CA 94107, USA along with a check for $10 (to cover printing and postage) payable to ‘‘Public Library of Science.’’ In addition, this published work and the nomenclatural acts it contains have been registered in ZooBank, the proposed online registration system for the ICZN. The ZooBank LSIDs (Life Science Identifiers) can be resolved and the associated information viewed through any standard web browser by appending the LSID to the prefix ‘‘http://zoobank.org/’’. The LSID for this publication is urn:lsid:zoobank.org:pub:CB77D4ED-B0B6-4F16- AAE7-231CF9F4DEBE. Clade names follow currently-used phylogenetic definitions [40]. Although the definition of Crocodylidae is context-depen- dent based on the position of Gavialis, the new species would be a crocodylid regardless of context. Systematic Paleontology Eusuchia Huxley 1873 Crocodylia Gmelin 1789, sensu Benton and Clark 1988 Crocodylidae Cuvier 1807 Crocodylus anthropophagus, new species urn:lsid:zoobank.org:act:052051B8-6503-42B3-8D7A- 9E7E49578401 Holotype specimen. NNHM-OLD-1001, partial skull and skeleton (Fig. 1, Fig. 2, Fig. 3). Referred Material. NHM R.5891, cranial and postcranial fragments; NHM R.5893, partial skull and skeleton (Fig. 4O–T; Fig. 5D,E); NHM R.5894, postcranial elements; and several specimens in the KNM collections. Most do not have catalogue numbers beyond their collection date and locality. Postcranial elements cannot be associated with particular cranial material (or with each other), but all available cranial evidence suggests a single crocodylian species in these units. The following refer to particular specimens figured in this paper: Crocodile Korongo (CROC K): OLD 62, partial skull (Fig. 4A– D); OLD 62 069/5866, right squamosal and quadrate ramus (Fig. 4E). Bell’s Korongo (BKII) channel: OLD 1960, right postdentary elements of mandible (Fig. 5A–B). Frida Leakey Korongo North I (FLKNI): cranial, mandibular, and postcranial material (Fig. 4F–N, Fig. 5C, Fig. 6, Fig. 7D). These are derived from at least two (and probably more) individuals; the braincase (Fig. 6) is from a substantially smaller animal than most other cranial fragments. Douglas Korongo, trench 1B (DK IB): scapula and humerus (OLD 62 54). Etymology. anthropos, Greek, human and phagos, Greek, eater, in reference to the evidence that this animal included hominids in its diet. Locality and Age. Plio-Pleistocene, Olduvai Gorge, northern Tanzania. The holotype was collected from the surface of Middle Bed I between Tuffs IB and IC, dated to 1.845+/20.002 and 1.839+/20.005 Ma, respectively [41]. FLKNI is near the type localities of Australopithecus boisei and Homo habilis and is from Upper Bed I. The DK locality also lies within Bed I. NHM R.5891 is from Bed I, and NHM R.5893 is from Bed II. Younger material from BK II (upper Bed II) and CROC K (Bed III or IV) is also referred to this species. Labels on KNM specimens from CROC K specify Bed IV, but published reports merely put crocodile remains from CROC K somewhere in Beds III or IV [35]. An additional PLoS ONE | www.plosone.org 2 February 2010 | Volume 5 | Issue 2 | e9333