Dental nomenclature in Ruminantia: Towards a standard terminological framework

Dental characters have always been important in mammal taxonomy and systematics. This is primarily due to the fact that the mammalian fossil record largely consists of teeth, which show tremendous morphological diversity throughout the group and sufficient variability in size and shape to be used as major classifying traits in subordinate taxa. To describe and compare tooth crown morphologies, their individual elements are named by specified nomenclatures (see, e.g. Thenius 1989). These usually comprise terms for the basic cusps and cuspids referring to the descriptive tritubercular terminology (protoconus, paraconus, etc.) of Cope, 1874 and Cope, 1883 and Osborn (1888) and continuative work. They are complemented with additional terms for apomorphic elements of the individual mammalian clades.In Ruminantia a variety of nomenclatures were applied in the past to describe dental features. This paper aims to clarify the meaning and correspondence of the array of previously used terms, focusing not only on permanent cheek teeth but also on deciduous premolars. Therefore, we synonymize the nomenclature used by various authors in table form to facilitate their identification and eventually their further use in a comparative way (e.g. in a phylogenetic analysis). Moreover, we propose a set of terms, based on these previous studies, which we consider most useful for future work on ruminant teeth.