1120
Journal of Paleontology
cf. Dryptosaurus sp. (morphotype A) Cope, 1866 Figure 2.6–2.14
Description.—The partial tooth included in NJSM 12436 is the incomplete tooth of a large theropod dinosaur, measuring 27.5mm high. This specimen is interpreted as a shed maxillary or dentary tooth based on its size and because it lacks a root. This tooth is distinct from NJSM 13734 in having a denticle count of 12 d/5mm basally (see below), which matches the condition in Dryptosaurus aquilunguis (Schwimmer, 2016). These denticles are peg-like and rectangular, strongly oriented apically. The smaller tooth included in NJSM 12436 bears interdenticular sulci on its distal carina (e.g., Currie et al., 1990; Smith, 2007; Hendrickx et al., 2015) that extend slightly onto the tooth and are, like the denticles, oriented parallel to the base of the tooth. These denticles are approximately twice as long mesiodistally than apicobasally. The mesial surface of NJSM 12436 is slightly recurved apically, matching the condition of NJSM 16601 and the teeth of Dryptosaurus aquilunguis more than that of NJSM 13734. The preserved portion of the basal end of NJSM 13734 is elliptical and suggests a labiolingually compressed, teardrop-shaped morphology consistent with the ziphodont condition. However, because of the fragmentary nature of the specimen, ziphodonty on NJSM 13734 cannot be confirmed. The mesial portion of the tooth is absent. However, NJSM 13734 is relatively well preserved compared to other specimens, suggesting the tooth was shed close to the site of its deposition (e.g., Denton et al., 2011). NJSM 13095 is another large theropod maxillary or dentary
tooth, measuring 27mm in CH. This tooth, which is ziphodont in morphology (CBW/CBL=0.53), has been abraded to a greater extent thanNJSM13734, but still preserves distal denticles that have a density of 9.5 denticles/5mm. This denticle count corresponds closely to the denticle density reported for the apical distal carina of the maxillary teeth of Dryptosaurus by Schwimmer (2016). NJSM 13095 is straightened distally, with a gently curved mesial outline.
Materials.—NJSM 12436, partial maxillary or dentary tooth (Fig. 2.6–2.8), NJSM 13095, partial maxillary or dentary tooth (Fig. 2.9–2.14).
Remarks.—NJSM 12346 and NJSM 13095 are assigned to Tyrannosauroidea based on the presence of the following combination of features: size, distally tapered labio-lingual depth, gentle curvature, and widely spaced, peg-like denticles. NJSM 12346 and NJSM 13095 are assigned to cf. Dryptosaurus due to having a similar basal distal carina denticle count of 12 denticles/5mm and apical distal carina denticle count of 9.5 denticles/5mm, respectively (Schwimmer, 2016). NJSM 13095 is also ziphodont in morphology, further allying the specimen with Dryptosaurus. Although NJSM 12346 may be ziphodont in morphology, which would further unite the tooth with Dryptosaurus (e.g., Brusatte et al., 2011), the presence of this morphology on NJSM 12346 is uncertain.
Tyrannosauroidea indet. (morphotype B) Figure 3
Figure 3. Partial tyrannosauroid maxillary or dentary tooth NJSM 13734 in labial (1), lingual (2) , and basal (3) views, with magnified view of denticles (4). Scale bar=10mm (1–3),=2mm (4).
Description.—NJSM 13734 is the partial maxillary or dentary tooth of a large theropod dinosaur. This tooth is slightly recurved and labiolingually narrow basally. The partial tooth preserves the mesial carina and approximately one quarter of its the denticles, which are small (16 denticles/5mm),widely spaced, peg-like, and strongly oriented mesially. The distal denticles of NJSM 13734 are much smaller than those of NJSM 12436, with 17 denticles/
5mmbasally.This denticle density is similar to but exceeds that of the teeth of Appalachiosaurus (e.g., Carr et al., 2005; Schwimmer et al., 2015; Schwimmer, 2016).The denticles inNJSM13734 are ~2.5 times longer mesiodistally than apicobasally. Interdenticular sulci that extend slightly onto the tooth surface are also present on NJSM13734 and are about the same dimensions as the denticles themselves. The tooth, though only partially preserved, is labio- lingually compressed basally (Fig. 2.11). The estimated mesio- distal length of the base of the tooth when complete is 12–15mm, and the preserved labiolingual width of the base is 6mm. Thus, the tooth may have been ziphodont when complete, allying the large tyrannosauroid taxon to which it belonged with Drypto- saurus aquilunguis (e.g., Brusatte et al., 2011).
Material.—NJSM13734, maxillary or dentary tooth (Fig. 3.1–3.4).
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