riented microwear on a tooth of Edestus minor (Chondrichthyes, Eugeneodontiformes): Implications for dental function

Palaeontologia Electronica

Wayne M. Itano¹ 

[1] University of Colorado

关键词: Wayne M. Itano;    Pennsylvanian;    Texas;    Chondrichthyes;    Edestidae;    sharks;    functional morphology;    dental microwear;   

DOI  :  10.26879/831

学科分类：地质学

来源: Palaeontologia Electronica

【 摘 要 】

The symphyseal tooth whorls of the Carboniferous chondrichthyan Edestus consist of files of teeth having sharply-pointed, serrated crowns, joined at their bases. A single tooth whorl was present in each jaw. How these tooth whorls functioned is unclear, since their convex curvature allows only a few of the most lingual crowns of opposing tooth whorls to occlude. Rather than working in opposition, like scissors, the more labial teeth might have been used to cut and disable prey with a vertical motion of the anterior part of the body. Provided the scratches observed on the surface of Edestus teeth can be inferred to have been generated in the process of feeding, their orientation might be used to distinguish whether the teeth were used mainly in occlusion, to cut prey trapped between the jaws, or mainly to cut prey situated outside the oral cavity. Edestus minor teeth having unusually good surface preservation were examined for microwear. The teeth are from the Strawn Group (Desmoinesian, Middle Pennsylvanian) of San Saba County, Texas, USA. The best-preserved crown surfaces display scratches 50 to 500 micrometers long. The scratches are oriented predominantly transversely to the basal-apical axis. This observation appears to support the vertical slashing hypothesis. However, the possibility that interaction with the substrate contributed to the observed wear cannot be discounted.

【 授权许可】

CC BY