Richardoestesia Currie, Rigby, and Sloan,, 1990

Brand, Nickolas A., Heckert, Andrew B., Sanchez, Israel, Foster, John R., Hunt-Foster, Rebecca K. & Eberle, Jaelyn J., 2022, New Late Cretaceous microvertebrate assemblage from the Campanian-Maastrichtian Williams Fork Formation, northwestern Colorado, USA, and its paleoenvironmental implications, Acta Palaeontologica Polonica 67 (3), pp. 579-600 : 591

Genus Richardoestesia Currie, Rigby, and Sloan,

1990 Type species: Richardoestesia gilmorei Currie, Rigby, and Sloan, 1990 ;

Dinosaur Park Formation, Upper Cretaceous.

cf. Richardoestesia sp.

Fig. 7A .

Material.— MWC 8865 , tooth; from the Campanian–Maastrichtian , Williams Fork Formation, J &M site, northwest Colorado, USA .

Description.—Laterally compressed and serrated tooth with rounded denticles on the mesial and distal crown margins. Serrations along the distal surface are larger when compared to those on the mesial surface ( Williamson and Brusatte 2014). Given the size of the tooth and relative sizes of the rounded denticles on either margin, we tentatively refer this tooth to Richardoestesia sp.

Remarks.—We refer one tooth to the genus Richardoestesia . The tooth is slightly recurved. The serrations along the distal surface of the crown are relatively large and rounded. The tooth was cracked in two places all the way through the crown when recovered. The specimen has since broken, although photomicrographs were taken before this occurred ( Fig. 7A ). Without more material, it is impossible to ascertain a species level identification of this tooth. Teeth assigned to Richardoestesia are relatively common in the Upper Cretaceous of North America ( Sullivan and Lucas 2006), and Richardoestesia gilmorei has been reported from the Williams Fork Formation by Diem (1999).

Figures

Fig. 7. Representative theropod dinosaur teeth from the J&M site,Colorado, USA, Williams Fork Formation, Campanian–Maastrichtian, Upper Cretaceous. A. cf. Richardoestesia sp., MWC 8865, tooth crown in labial view (A1), mesial (A2) and distal (A3) serration detail views.B. Dromaeosauridae indet., MWC 8872, tooth crown fragment in lingual (B1), distal (B2) and mesial (B3) serration detail views. C. Hadrosauridae indet., MWC 8896, tooth crown in occlusal (C1) and lateral (C2) views.