The diprotodontian ‘hypocone’ revisited

Abstract

A controversy has arisen over the terms to be applied to certain cusps of the marsupial upper molar as the result of divergent views over the precedence of functional or structural considerations. It is generally accepted that the posterolingual cusp in the molars of mammals has arisen in a number of ways. Regardless of origin they are often termed a ‘hypocone’ because of their analogous occlusal relationship with the trigonid of the lower molars. In diprotodontian marsupials, however, the posterolingual cusp is homologous with the metaconule, as demonstrated by its linkage through the postprotocrista with the protocone and metacone. This structural relationship is important to the determination of homology, which is fundamental to phylogeny reconstruction.