Family CERATOPSIDAE

Fig. 10

Material: Teeth: UCM 37878 (UCMP-V5711) H 6 mm, W 3.8 mm; UCM 43526 (UCMP-V5711) H 2 mm, W 2.5 mm; UCM 45057 (UCMP-V 5711) H 3.6 mm, W 3.8 mm; UCM 45058 (UCMP-V 5711) H 3.5 mm, W 4.1 mm; and UCM 45059 (UCMP-V5711) H 4 mm, W 3.7 mm.

Discussion: Only UCM 45059 is heavily worn. Unworn teeth have a triangular enameled face with a vertical medial ridge (Fig. 10). Small denticles are present along the upper edge of the enameled surface. Unlike adult ceratopsian teeth, these have a single unbifurcated root, a condition Hatcher and others (1907) noted for young incipient teeth. It is doubtful that these small teeth are incipient teeth of an adult, because they are well developed and have a long root, which is unlike the short, thin-walled, open root of the adult. It is probable that the root became bifurcated as the animal matured. Because there are two genera of ceratopsians ( Triceratops and Torosaurus) in the Lance and Hell Creek formations, it is not possible to be more specific in the identification.