Ecological polarity in primate tion

Relationships of the catarrhine primates based on morphological similarity are presented and then combined with habitat data to determine polarity of ecological change in the catarrhines. The ancestral habitat of two sister-groups is estimated by combining that of the sister groups, so that if they share one habitat type the ancestral condition is taken to be that type, or if they differ the ancestral condition is taken to be both alternatives. Analysed in this way the ancestral habitat preference of the Catarrhini is tropical lowland forest, and while the Hominoidea retain this primitive condition, the Cercopithecoidea are derived with a savanna habitat preference. Most hominoids retain the primitive forest habitat condition, and those groups that are associated with woodland-savanna habitats, notably the ramapitbecines and hominines, therefore share a derived habitat preference. There is no evidence, however, that this arose through common ancestry, and it is concluded that the functional similarities between the two groups could have arisen through parallel adaptation to the same habitat type. Similarly, many of the extant cercopithecoid groups that are now forest living may have re-entered forest independently. The derived savanna habitat preference of the cercopithecoids is linked with a number of morphological characters that also are derived with respect to catarrhine ancestry, and these include their terrestrial and/or their above-branch adaptations, and their specialized digestive, dietary and dental adaptations. In contrast, the hominoids that retain the primitive catarrhine habitat preference also retain the primitive condition in all these characters.