The diprotodontian 'hypocone' revisited

A controversy has arisen over the terms to he applied to certain cusps of t he marsupial upper molar as the result of divergent views over the preceden ce of functional or structural considerations. It is generally accepted tha t the posterolingual cusp in the molars of mammals has arisen in a number o f 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 homolog ous with the metaconule, as demonstrated by its linkage through the postpro tocrista with the protocone and metacone. This structural relationship is i mportant to the determination of homology, which is fundamental to phylogen y reconstruction.