Variation in the lower dentition of a late Blancan (Late Pliocene)
Cotton rat (Sigmodon
Two late Blancan (late Pliocene) localities from the west coast of Florida, Inglis 1A and Inglis 1C, produced a large number of specimens of the extinct cotton rat Sigmodon curtisi. The teeth recovered represent a wide range of wear stages. These large samples provide a rare opportunity to examine variation within the species. No correspondence was found between the wear stage and the number of roots on the lower first molar (m1). Qualitative changes, however, were pronounced. The anteroconid is the last feature on the occlusal surface of the m1 to obtain the mature wear pattern. Subsequently, the lower second and third molars develop an enamel pit from the constriction of the second buccal reentrant angle by the anterior cingulum. With further wear, the lingual reentrant angles become constricted in all lower molars, and eventually are completely worn away.
KEY WORDS: Blancan; Pliocene; cotton rat; Sigmodon; Inglis
PE Article Number:
Copyright: Society of
Vertebrate Paleontology November 2011
Submission: 15 June 2007. Acceptance: 29 March 2011