Parasites in primates : indicators of the host phylogeny

The use of parasites to infer host relationships is well established. This thesis applies this concept to the parasites in catarrhine primates. Three catarrhine phylogenies are outlined, a 'troglodytian', a 'hylobatian' and a 'pongoian' hypothesis. The existence of these conflicting host phylogenies raises the possibility of using parasite data as an a priori tool to help choose between them. The central theme of this thesis is to see whether any one of the three primate phylogenies better explains the available parasitological evidence. Parasite data are of a different class than the data usually used to infer host relationships, and have thus been considered consilient. Two types of parasite data have been used to infer primate relationships. These include analyses of presence/absence checklists, and analyses of particular groups of parasites in primates. Both these types of data are featured in this thesis. The presence/absence data were analysed using a percentage calculation of shared parasites, and a phylogenetic protocol. The results of these analyses show that humans and cercopithee ids have the most parasites in common. Thus, this evidence can not be used to support any one of the three primate phylogenies outlined. With the exception of humans the presence/absence data support a coevolutionary pattern between primates and their helminth parasites. The divergence of humans from this pattern is the result of a number of host transfers to humans by parasites normally found in cercopithee ids. A phylogenetic analysis of twelve species in three subgenera of the hookworm genus Oesophagostomum is also presented. This analysis was based on twenty two characters and the overall c-index for the proposed phylogeny was 80%. The phylogeny of these parasites is more supportive of the 'troglodytian' primate hypothesis. This conclusion is however, dependant on the absence of a coevolved Oesophagostomum species in orangutans. Regardless of which primate phylogeny is correct the relationship between the Oesophagostomum species and primates appear to be predominantly coevolutionary. The biogeographic relationships between Oesophagostomum species and their hosts are also discussed. The support of the Oesophagostomum phylogeny for the 'troglodytian' hypothesis is in conflict with a previous study in which the pinworms (Enterobius) in primates were shown to support the 'hylobatian' primate hypothesis. These findings, along with the presence/absence results suggest that the parasite data at present do not support any one particular primate phylogeny. There are however, no parasite data supporting the 'pongoian' primate hypothesis.Science, Faculty ofZoology, Department ofGraduat