Figure 1. Cranial remains of NNHM-OLD-1001, holotype, Crocodylus anthropophagus, preserving features diagnostic of the species. Right premaxilla in medial (A), ventral (B), dorsal (C), and lateral (D) view; partial left squamosal in dorsal (F), posterior (G), and lateral (H) view; left lacrimal in dorsal view (J); frontal with adjoining parts of prefrontals in dorsal (K) and left lateral (L) view. Specimens are compared with Crocodylus niloticus (KNM OR44, E; AMNH 7136, right side reversed, I; KNM OR54, M). Scale = 1 cm. doi:10.1371/journal.pone.0009333.g001 specimen from Bed IV (NHM R.5892) may also pertain, but diagnostic features were not preserved. All of these predate the Holocene. Diagnosis. Crocodylus with a prominent triangular projection (‘‘horn’’) at the posterolateral corner of each squamosal dorsal to otic aperture at maturity; projection has discrete boundaries in lateral and posterior view. Pair of thin crests on rostrum corresponding to the maxillary-nasal sutures. Maxillary ramus of ectopterygoid may not be forked, though expression of the cleft varies intraspecifically in most modern Crocodylus. External naris opens anterodorsally rather than dorsally. Lacks the elongate Extinct Horned Crocodile preorbital crest typical of Indo-Pacific Crocodylus, and lacks the median rostral boss diagnostic for Neotropical Crocodylus. Description. The premaxillae (Figs. 1A–D and 4A,B) form the anterior and lateral margins of the narial aperture and are separated by the nasals medially behind the naris. Each bears an acute posterior process between the nasal and maxilla extending back to approximately the second maxillary alveolus. The naris opens anterodorsally, and the dorsal surface posterolateral to the narial rim and along the premaxillary-maxillary suture is inflated. The premaxillae surround a circular incisive foramen ventrally, and there is a deep occlusal pit anterolateral to the incisive foramen. The palatal lamina of each premaxilla has a convex posterior margin, causing the premaxilla-maxilla suture on the palate to form a shallow W. The right premaxilla of the holotype preserves three complete alveoli and the anterior margin of a fourth (Fig. 1B). There is a diastema between the first and second, and the second is smaller than both the first and third. The fourth is incomplete, but was larger than the third. The second alveolus is sometimes crowded away by the third during ontogeny in Crocodylus [42,43], but we do not believe this happened here; in crocodiles lacking the second alveolus, diastemata separate the three anteriormost alveoli, and the second remaining alveolus (originally the third) is similar in size to the first. Alveoli are imperfectly preserved on the KNM CROC K OLD 62 snout, but a small alveolus adjacent to the premaxilla-maxilla suture shows that C. anthropophagus had five premaxillary alveoli. None of the preserved maxillae are complete. One partial left element (Fig. 4G) preserves a complete series of 13 alveoli, of which the fifth behind the premaxilla is the largest. The maxillary palate is vaulted anteriorly, and the first six alveoli extend ventral to the palatal ramus. A small pit at the back of the toothrow might be the remnant of a fourteenth alveolus that no longer held teeth. Occlusal pits for the dentary teeth lie between the first ten alveoli. KNM FLKNI indicates that the suborbital fenestra extended anteriorly to the level of the ninth maxillary alveolus (Fig. 4J), and assuming the ectopterygoid was adjacent to four maxillary alveoli (see below), the maxillary ramus lateral to the fenestra bore five alveoli. An isolated right maxilla (KNM FLKNI, Fig. 4H–K) preserves the medial wall of the caviconchal recess, revealing a linear array of shallow pits. The circular posterior opening to the recess lateral to the nasopharyngeal duct is approximately medial to the eighth maxillary alveolus. The dorsal surface of the maxilla bears a prominent circular protuberance posterodorsal to the fifth alveolus. The surface expands dorsally parallel to the sutural contact with the nasal, forming a sharp linear crest. Each nasal bears a short conical process extending into the narial aperture. The nasals flare posteriorly as they approach the posterior tips of the premaxillae, but the point at which their lateral margins adopt a parasagittal orientation is not preserved. They taper posteriorly where they pass adjacent to the lacrimals and prefrontals, forming short triangular processes separating the frontal from each prefrontal. None is complete, but the preserved jugal fragments (Figs. 1B– E, 4S,T, 6A,B) collectively indicate the shape of the element. The anterior ramus is flat and passes laterally over the maxilla. It forms the ventral margin of the orbit and bears one or two large foramina between the medial surface and postorbital bar. The posterior ramus is dorsoventrally shorter and mediolaterally thicker, tapering to a point posteriorly. It forms the ventral margin and posteroventral corner of the infratemporal fenestra. The jugal component of the postorbital bar is hemicylindrical, bearing a crescentic articulation facet for the ectopterygoid and postorbital medially. PLoS ONE | www.plosone.org 3 February 2010 | Volume 5 | Issue 2 | e9333