Description
Original description after Cicimurri, Ebersole & Martin (2020) [28668]:
First upper anterior teeth. These teeth, not exceeding 25mm in total height, are slightly asymmetrical in labial view. The main cusp is very narrow, is slightly distally curving (Fig. 3b–d), and has a weakly sigmoidal profile (Fig. 3d). Mesial and distal cutting edges are sharp, smooth, and subparallel but never reach the base of the main cusp (Fig. 3d). There may be a minuscule tubercle or very short ridge near the base of the main cusp, well separated from the main cutting edge, on one or both sides of the crown. A single pair of diminutive triangular cusplets is located at the crown foot. When present, the short ridge is connected to the lateral cusplet (Fig. 3e). The labial face of the main cusp is smooth and flat except for where basal convexity occurs at each side of the labial crown foot. The lingual face is very convex and generally smooth, although faint longitudinal ridges on the lower half were occasionally observed. The root is bilobate and has a large lingual boss that is bisected by an elongate and deep nutritive groove (Fig. 3a). A conspicuous dental band (often deeply impressed) occurs at the lingual crown foot. Root lobes are rather short and may be cylindrical or mesiodistally compressed, and the mesial lobe is slightly longer than the distal lobe (Fig. 3b, c).
Second upper anterior teeth. In our sample, the largest complete tooth from this file measures 20mm in total height, which is smaller than the largest first upper anterior tooth available to us. Larger second upper anterior teeth are present in our sample, but they are incomplete and represented fragmentary specimens. The main cusp is tall and narrow, sharply tapering (Fig. 3g, h), weakly sigmoidal in profile (Fig. 3i), and more distally inclined than the main cusp of the first anterior tooth (Fig. 3h). Cutting edges are subparallel, and although they do not reach the cusp base, the edges extend further basally than on teeth from the first anterior file. The labial face is smooth and flat to very weakly convex, but the lingual face is very convex and may bear faint vertical ridges on the lower half. The main cusp is flanked by a single pair of small cusplets that are triangular, are sharply pointed, and have distinct cutting edges. A short cutting edge or small denticle, well separated from the main cutting edge, may occur on the medial side of one or both lateral cusplets (Fig. 3j). The lingual dental band is conspicuous and may be impressed (Fig. 3h), and the robust lingual root boss bears a thin nutritive groove (Fig. 3f, h). The root is bilobate, and although the lobes are of nearly the same length, the mesial lobe is thin and pointed basally, whereas the distal lobe is wide and rounded basally (Fig. 3g, h).
Third upper anterior teeth. The largest specimens do not measure more than 20mm in total height. The main cusp is broad-based but sharply tapering, is strongly distally inclined but with weak mesial curvature (Fig. 3l, m), and has only a very weak sigmoidal profile (Fig. 3n). The labial face is flat and smooth, but the lingual face is moderately convex and usually smooth. The smooth cutting edge is continuous across the entire main cusp. A single pair of broadly triangular cusplets flanks the main cusp, and these cusplets bear sharp cutting edges (Fig. 3o). A small denticle may be located medially to the lateral cusplet, on one or both sides of the main cusp. The lingual dental band is conspicuous and may be impressed (Fig. 3m). The root is bilobate with highly divergent lobes, with the mesial lobe being much more elongated than the distal one (Fig. 3l). The lingual boss is thin and shelflike, bisected by a thin nutritive groove (Fig. 3k, n).
Intermediate teeth. No intermediate teeth have been identified in the available sample.
Upper lateral teeth. Upper lateral teeth can be differentiated from the anterior teeth in that the main cusp is labiolingually thinner, flat to only weakly sigmoidal in profile (Fig. 3s), and distally inclined, and the base is broader. The smooth cutting edge is continuous across the entire main cusp, reaching the crown foot. The mesial and distal cutting edges may be straight, but more often the main cusp appears distally curving because the mesial edge is slightly convex and the distal edge straight to concave. One or two tiny denticles may occur on one or both sides of the crown foot, adjacent to lateral cusplets (Fig. 3t). A single pair of broadly triangular, tall, sharply pointed cusplets flanks the main cusp (Fig. 3q). The lingual dental band is impressed. The bilobate root bears a small lingual boss that is bisected by a deep nutritive groove (Fig. 3p, r). Root lobes are rather short, wide, and divergent (Fig. 3r). Within the first few lateral files, the mesial root lobe is more elongated and thinner than the distal lobe, but other lateral teeth have more equidimensional root lobes. Total tooth height exceeds root width. Within our sample of upper lateral teeth, it appears that the crown decreases in size but becomes more strongly distally inclined towards the commissure.
Upper posterior teeth. No upper posterior teeth have been identified in the sample.
First lower anterior teeth. Teeth from this file are not known to exceed 15mm in total height. The main cusp is very narrow and sharply inclined mesially, may be straight to distally curving, and has a strong lingual curve in profile but is not sigmoidal (Fig. 4a–c). The labial face is smooth and nearly flat, whereas the lingual face is very convex and smooth. Cutting edges are smooth, sharp, and subparallel and extend to the crown foot (Fig. 4e). A single pair of lateral cusplets flanks the main cusp, and in labial view the mesial cusplet appears to be located higher on the tooth than the distal cusplet (Fig. 4c). The cusplets are small, triangular, sharply pointed, and divergent. The root is laterally compressed, weakly bilobate (mesial lobe is shorter and narrower than the distal lobe), and the large lingual boss (Fig. 4a, d) is bisected by an elongate nutritive groove (Fig. 4b). Crown height slightly exceeds root height.
Second lower anterior teeth. Teeth in this position are the largest in the available sample, reaching 24.4mm in total height. The main cusp is tall, narrow, and erect and has a sigmoidal profile (Fig. 4f–h). The labial face is smooth and flat, whereas the lingual face is very convex and may bear fine longitudinal ridges on the lower half. The cutting edges are smooth and appear biconvex due to medial curvature (Fig. 4g), and the edges end well before the cusp base. A small node or short ridge may occur near the crown base, well separated from the main cutting edge, on one or both sides of the main cusp. A single pair of very small, triangular lateral cusplets flanks the main cusp (Fig. 4h). When present, the short basal ridge is closely connected with the lateral cusplet (Fig. 4j). The root is bilobate with a large lingual boss that is bisected by a deep nutritive groove, and the thin dental band is impressed (Fig. 4f, g, i). Root lobes are elongated but of equal length, although the distal lobe may be slightly wider. Root height is roughly one-third (30 %) of the total tooth height.
Third lower anterior teeth. These teeth (Fig. 4k–n) are very similar to those of the second lower anterior file. They can be distinguished by their less convex cutting edges and root with a more elongated and narrower mesial lobe compared to the distal lobe (Fig. 4l, m).
Fourth lower anterior teeth. The main cusp is erect and slightly curved distally and has a sigmoidal profile (Fig. 4p– r). The cutting edges are smooth and convex apically but otherwise subparallel (Fig. 4r), nearly reaching the crown foot. The labial face is weakly convex and smooth, whereas the lingual face is very convex and only occasionally bears faint longitudinal ridges. A very convex ridge or small denticle, well separated from the main cutting edge, may occur on one or both sides of the cusp base (Fig. 4t). A single pair of broadly triangular cusplets flanks the main cusp. The lingual dental band is impressed. The lingual boss is indistinct, bisected by a thin nutritive groove (Fig. 4s, q). The bilobate root has a very elongated and narrow mesial lobe and very short, rounded distal lobe (Fig. 4q, r). Root height represents 30% (one-third) of the total tooth height. Teeth from this file are somewhat similar to the third upper anterior tooth, but they differ in that the main cusp is rather erect and has an obvious distal curvature (Fig. 4r). In contrast, the third upper anterior tooth has a highly distally inclined cusp that exhibits distinctive mesial curvature (i.e., Fig. 3l, m).
Lower lateral teeth. In general, the main cusp is broadbased but sharply tapering, vertical to very slightly distally inclined, and flat to weakly sigmoidal in profile (Fig. 4u–w). The labial face is smooth and flat to very weakly convex, but the lingual face is convex and may bear faint vertical ridges on the lower half. The cutting edges are smooth and sharp and extend to the very base of the main cusp (Fig. 4w). The mesial and distal cutting edges are usually straight, but some teeth exhibit a mesial edge that is somewhat concave. The base of the cutting edge may be smooth and continuous or punctuated by one (rarely two) rounded-to-pointed denticle (or denticles; Fig. 4y). The main cusp is generally flanked by a single pair of tall, triangular, sharply pointed lateral cusplets (Fig. 4v, w), but an inconspicuous second cusplet may occur on one or both sides of the crown. The dental band is thin and impressed. The bilobate root bears a conspicuous boss that is bisected by a deep nutritive groove (Fig. 4v, x). The lobes are divergent, roughly of equal length, and separated by a V-shaped interlobe area, and their ends may be rounded or pointed (Fig. 4v, w). Root width is approximately two-thirds of the total tooth height. Teeth within the first few lateral files have a slightly wider mesial lobe compared to the distal lobe (Fig. 4v, w). Other lateral teeth have more equidimensional root lobes and are difficult to place into a specific file. Within our sample of lower lateral teeth, it appears that the crown decreases in size and becomes slightly distally inclined towards the commissure.
Lower lateral teeth are distinguished from upper lateral teeth in having erect main cusps as opposed to conspicuously distally inclined ones, and root lobes are less robust.
Lower posterior teeth. The lower posterior teeth are similar to the lower lateral teeth, but they are significantly smaller in size and have a much shorter main cusp (Fig. 4z–ad). The total root width is greater than the overall tooth height, the latter of which does not exceed 7mm (Fig. 4aa, ab). No denticulations are present on any of the lower posterior teeth observed.

Remarks
shark-references Species-ID=15990;

References