Brownstein—On the theropods of the Ellisdale Site (Campanian) 92(6):1115–1129


Remarks.—NJSM 13734 is referred to Tyrannosauroidea on the basis of the following combination of features: size, having a D-shaped cross-section basally, being gently curved towards its apex and distally tapered in its labiolingual width, and possessing peg-like denticles that increase in density towards its base. NJSM 13734 is referred to a second morphotype of tyrannosauroid based on having denser denticles than the other Ellisdale tyrannosauroid teeth for which distal denticles are preserved (NJSM 12436).


Ornithomimosauria Barsbold, 1976 Ornithomimosauria indet. Figure 4


Description.—NJSM 14686 is smaller than NJSM 14682 in all dimensions (Table 1), measuring 67 mm long proximodistally. The bone is slightly eroded, though most of the bone surface is well preserved and not noticeably abraded. Distally, the hemi- condyles are separated by a very slight sulcus, which transitions to a shallow, proximally extending hyperextensor pit dorsally. The collateral ligament pits are subovoid and deep. Ventrally, the two distal hemicondyles form a concavity just proximal to the distal articular surface. In lateral and medial views, the dorsal surface is flattened and the ventral surface is gently arched. In dorsal and ventral views, the lateral and medial sur- faces are also gently arched and gently curved outward towards the proximal end in expansion. The proximal end is appreciably wider than the distal (Table 1), and the proximal end bears pointed processes on its ventral corners that form a shallow concavity ventrally. The proximal end, though not noticeably eroded, lacks a vertically oriented projection, and there is no rim surrounding the proximal articular facet. NJSM 14686 is assignable to Ornithomimosauria based on


the proximally projecting ventral processes on the bone, a morphology found in both basal and derived ornithomimosaurs (e.g., Osborn, 1921, fig. 3a; Osmólska et al., 1972, fig. 17, pl. 49;


1121


Kobayashi and Barsbold, 2005a, fig. 6.10G, 6.10H, 2005b, fig. 17B; Choiniere et al., 2012, fig. 14; Cullen et al., 2013, figs. 2, 3; McFeeters et al., 2016, fig. 11;Tsogtbaatar et al., 2017, fig. 4).The specimen’s gently arched medial and lateral surfaces, flattened dorsal surface, smaller size when compared to the known pedal phalanges of eastern Tyrannosauroids, and shallowhyperextensor pit are also consistentwith this assignment (e.g., Lambe, 1917, fig. 49; Osborn, 1921, fig. 3a; Osmólska et al., 1972, fig. 17, pl. 49; Carr and Williamson, 2000, figs. 3, 4, 8, 15; Holtz, 2004; Carr et al., 2005, supplemental information; Kobayashi and Barsbold,


2005a, fig. 6.10G, 6.10H, 2005b, fig. 17B; Choiniere et al., 2012, fig. 14; Cullen et al., 2013, figs. 2, 3; Farlow et al., 2013; McFeeters et al., 2016, fig. 11; Tsogtbaatar et al., 2017, fig. 4). In form, the proximally projecting processes onNJSM14686 are not aswell developed as in ornithomimids (e.g.,Osborn, 1921, fig. 3a;


Osmólska et al., 1972, fig. 17, pl. 49; Kobayashi and Lü, 2003, fig. 24; Cullen et al., 2013, figs. 2, 3;McFeeters et al., 2016, fig. 11; Tsogtbaatar et al., 2017, fig. 4). Rather, the specimen is more similar to the pedal phalanges III of Harpymimus, Nedcolbertia, an ornithomimosaur from the Aptian–Albian of China, and of ornithomimosaurs from the Arundel Clay of Maryland in the extent of its proximally oriented ventral processes and the ratio between its dorsoventral height andmediolateralwidth proximally (e.g., Table 1;Gilmore, 1920;Kirkland et al., 1998; Shapiro et al., 2003; Kobayashi and Barsbold, 2005a). Thus, it may be that the specimen represents an ornithomimosaur species basal to those found in thewest during the Campanian, a condition that has been foundwith other dinosaur groups onAppalachia (e.g., Schwimmer, 1997; Carr et al., 2005; Brusatte et al., 2010; Prieto-Márquez et al., 2016a, 2016b). Further research into Appalachian ornithomimo- saurs from the time of theWestern Interior Seaway will be needed to test this hypothesis.


Material.—NJSM 14686, a pedal phalanx II-2 (Fig. 4.1–4.6).


Remarks.—NJSM 14686 is referred to Ornithomimosauria based on the following combination of features: proximally projecting ventral spurs (Fig. 4.1, 4.2), shallow hyper-extensor pit, and long form with gently proximodistally arched lateral and medial surfaces.


Maniraptora Gauthier, 1986


Dromaeosauridae Matthew and Brown, 1922 Dromaeosauridae indet. morphotype A. Figure 5


Figure 4. Ornithomimosaur pedal phalanx NJSM 14686 in lateral (1), medial (2), dorsal (3), ventral (4), proximal (5), and distal (6) views. Arrows point to ventral spurs. Scale bar=50mm.


Description.—NJSM 14158 is the partial large tooth of a ther- opod dinosaur, measuring 25mm in CH. The mesial and distal carinae are both preserved, though middle portion of the crown is only partially present. The tooth is clearly dromaeosaurid based on the apically recurved distal denticles on the distal carina and the extremely small size of the mesial denticles, which are rectangular. The distal denticles in NJSM 14158 differ from those in other dromaeosaurid specimens from Ellisdale in being twice as long mesiodistally than apicobasally, rectangular, and slightly (≥50º) rather than heavily (≤40º) inclined towards the crown apex. Small interdenticular sulci separate each distal denticle and do not extend onto the crown. The mesial denticles are very small and mesiodistally flattened,


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