Tarsier brain component composition and its implications for systematics

The taxonomic position of Tarsius has been a topic of some debate. Recent molecular and anatomical studies have shown that tarsiers share a number of derived traits with Anthropoids. These include aspects of their reproductive biology and aspects of their olfactory and visual systems. It has, therefore, been suggested that, despite a number of convergences with strepsirhine primates, tarsiers should be classified with the Anthropoid primates. We use comparative analysis of relative primates brain part volumes to determine whether Tarsius should be classified as a Haplorhine. We show that, for each of seven brain components whose relative size discriminates unequivocally between Strepsirhines and Haplorhines, the tarsiers fall in the Haplorhine distribution. These results confirm their clasification with the Haplorhines.