Figure 3. Postcranial remains of NNHM-OLD-1001, holotype, Crocodylus anthropophagus. A, atlas intercentrum, anterior view. B, axis centrum and odontoid process, right lateral view. C, cervical vertebra, right lateral view. D, dorsal osteoderm, posterior view. E, dorsal osteoderm, dorsal view. F, proximal half of left humerus, ventral view. G, left ilium, medial view. H, metapodial, dorsal view. Scale = 5 cm. doi:10.1371/journal.pone.0009333.g003 for the postorbital, suggesting that the dorsal surface of the postorbital in that specimen would have been more planar. The squamosal forms the posterolateral margin of the supratemporal fenestra. The lateral and posterior margins of the fenestra are almost linear, intersecting at a nearly right angle (Figs. 1F, 4M). The squamosal and postorbital together form the roof of the external otic recess, and the cloverleaf-shaped otic aperture itself is bordered posterodorsally by the squamosal. The lateral squamosal groove for the ear flap musculature is dorsoventrally broad (Figs. 1F, 4N). The squamosal bears a flat ventrolateral ramus that forms the anterior surface of the paroccipital process. The dorsolateral margin of the squamosal forms a prominent dorsal hornlike projection. This takes the form of a mediolaterally flattened lamina and is triangular in lateral view, with an apex dorsal to the otic aperture and posterolateral to the supratemporal fenestra. It arises abruptly from the dorsal surface of the skull table. The apex is sharp in the holotype, and the lateral squamosal groove is continuous with a sulcus on the lateral surface of the horn (Fig. 1F–H). Other specimens suggest a more rounded apex and a broadly convex lateral surface (Fig. 4L–N). The parietal is incompletely known. Its articulation surface for the frontal is concave, and it did not contribute to the supratemporal fenestra. Whether its dorsal surface was flat is unknown, but it did not expand laterally as it approached the squamosal and, hence, did not contribute to the squamosal horn. The quadratojugal lies between the jugal and quadrate. The ascending ramus is not completely preserved, but based on sutural surfaces on the quadrate and jugal, it formed nearly all of the posterior margin of the infratemporal fenestra, extending from just dorsal to the posteroventral corner to nearly to its dorsal apex; but whether it contacted the squamosal is unknown. The anterior process of the palatine was broad and formed a U- shaped structure at its anteriormost extent at approximately the level of the seventh maxillary alveolus (Fig. 4P). Posteriorly, the conjoined palatines (Fig. 4R) constitute the floor of the Extinct Horned Crocodile nasopharyngeal duct and the medial margins of the suborbital fenestrae. There are no discrete processes or expansions of the palatine into the fenestral space. Based on NHM R5893 (Fig. 4Q), the maxillary ramus of the ectopterygoid lies adjacent to four maxillary alveoli, possibly forming the medialmost wall of the posteriormost two alveoli. The anterior tip of the ramus appears to not be forked, although there is a modest concavity in its outline; the attachment scar for the ectopterygoid on the right maxilla of KNM FLKNI suggests the absence of an anterior cleft. The pterygoidal ramus (Fig. 2M,N) would have been fixed to the ventral surface of the pterygoid along the ventrolateral sides of the pterygoid wings. The pterygoids met the palatines along a linear sutural contact anterior to (and not intersecting) the internal choana (Fig. 4R). The pterygoid wings were broad and dorsoventrally thin, with flat articulation surfaces for the ectopterygoids ventrolaterally (Fig. 2K,L). The choana is partially preserved on a KNM specimen from FLKNI, and although the pterygoid surface was slightly elevated around the aperture, there was no choanal ‘‘neck.’’ Posteriorly, each pterygoid bears a small triangular process adjacent to the basioccipital, anterior to the lateral Eustachian foramen (Fig. 5C). Anteriorly, the quadrate forms the margin of the otic aperture and is pierced by a small circular preotic foramen (Figs. 2F, 4E, 5B). Its dorsolateral surface is smooth ventral to these openings, in marked contrast to the heavily pitted quadratojugal and jugal. The quadrate ramus bears a small foramen aereum on its dorsomedial surface, and the medial hemicondyle is dorsoventrally expanded relative to its lateral counterpart (Figs. 2G, 5C). There is a large muscle attachment tubercle on the ventral surface of the ramus (Fig. 2H). Details of the lateral braincase wall, including morphology of the laterosphenoid and prootic, are not preserved. Based on sutural contacts on the ventral surface of the frontal, the laterosphenoid capitate processes were oriented anterolaterally. The supraoccipital is likewise poorly known. Based on the holotype (Fig. 2J), it is triangular in posterior view, bearing sagittal crest that thickens dorsally. It would have been exposed on the skull table, but the shape of the dorsal exposure is not preserved. The exoccipital formed the posterior portion of the paroccipital process, narrowing laterally from the post-temporal fenestra (Fig. 2I,J). The cranioquadrate canal opens along the ventral margin of the exoccipital, passing anteromedially between the exoccipital and quadrate. Medially, the exoccipitals meet at the midline dorsal to the foramen magnum and extend posteriorly dorsal to the occipital condyle, where each is pierced by one or two small foramina for the hypoglossal nerve. The descending process of each exoccipital lateral to the main basioccipital body was pierced by a large common foramen for the ninth through eleventh cranial nerves and the jugular vein (lateral to the foramen magnum) and a carotid foramen lateral to the occipital condyle. The basisphenoid is unknown, but based on sutural surfaces on the basioccipital of NNHM-OLD-1001and KNM FLKNI, it would have formed an anteroposteriorly thin sheet ventral to the basioccipital. This sheet would have had a dorsoventrally short exposure on the posterior occipital surface based on the minimal distance between the ventral margins of the basioccipital and pterygoid (Fig. 5C). The basioccipital bears a robust spherical occipital condyle projecting from a main body (Figs. 2J, 5C). The main body bears a sagittal crest, and the exoccipital descending processes did not contribute to the modest basioccipital tubera. Notches for the lateral Eustachian openings are nearly lateral to the circular median Eustachian foramen. The main body is wedge-shaped in lateral view. PLoS ONE | www.plosone.org 5 February 2010 | Volume 5 | Issue 2 | e9333