Paronychodon lacustris, Cope, 1876

Carpenter, Kenneth, 1982, Baby dinosaurs from the Late Cretaceous Lance and Hell Creek formations and a description of a new species of theropod, Contributions to Geology, University of Wyoming 20, pp. 123-134 : 130

Paronychodon lacustris

Fig. 4

Material: Teeth: UCM 38288 (UCMP-V57 ll) H 4 mm, W 1.3 mm; UCMP 38459 (UCMP-V5711) H 1.7 mm, W 2.3 mm; UCMP 124990 (UCMP-V73087) H 3.4 mm, W 1.7 mm; UCMP 124991 (UCMP-V73087) H 4.8 mm, W 1 1.9. 9 mm; and UCMP 124992 (UCMP-V73087) H 4.3 mm, W 1.6 mm.

Discussion: Despite their small size, these teeth are clearly referable to Paronychodon lacustris. The anterior and posterior edges are vertical and parallel near the base ( Fig. 4 ), but then curve sharply posteriorly with the two edges meeting in a pointed tip. The teeth are laterally compressed, with one side being flat and covered by long ridges parallel to the edges of the crown. These ridges cover the one side of the crown between the tip and where the tooth curves posteriorly. Serrations may or may not be present on the posterior edge; none occurs on the anterior edge.

Figures

Figures 1-11. Fig. 1, Dromaeosauridae, tooth, UCM 39502. Fig. 2a-h, Sauromithoides inequalis: 20,, buccal view of hatchling left dentary, UCM 41666; c, lingual view; e, dorsal view; b, buccal view of left dentary, NMC 8540 (cast); d, lingual view; f, dorsal view; g, lateral view of hatchling basioccipital, UCM 43218; and h, ventral view. Fig. 3a-c, teeth of Pectinodon bakkeri: a, holotype, UCM 38445; b, paratype, UCM 38446; and c, paratype, UCMP 73098. Fig. 4, Pararıychodon lacustris, tooth, UCMP 124990. Fig. 5a, b, Tyrannosauridae: a as lateral view of UCMP 119853; and b, posterior view. Fig. 6, Theropoda, tooth, UCMP 124987. Fig. 7a, b, tooth of Aublysodon mirandus: a! lateral view of UCMP 124406; and b, posterior view. Fig. 8, Thescelosaurus sp., tooth, UCMP 124973. Fig. 9, Hadrosauridae, tooth, UCM 45060. Fig. 10, Ceratopsidae, tooth, UCM 45057. Fig. 11, Ankylosaurus magniventris, tooth, UCMP 124399. Heavy bars to left of specimens = 2 mm.