Parasite-Host Associations in Pinworms (Trypanoxyuris spp.) From Spider Monkeys (Ateles spp.)

Pinworms of primates are highly host-specific parasites that, in several lineages, are known to share their evolutionary history with that of their hosts. However, for many primate clades, pinworm diversity has been incompletely assessed, leaving some groups of hosts entirely unexplored and large geographic gaps in our knowledge of primate-pinworm associations. In this study, morphological and molecular data (28S rDNA and COI mtDNA) were integrated to assess pinworm diversity across five spider monkey taxa (Ateles spp.) from Mexico to Ecuador. Only two species of pinworms were found parasitizing Ateles hosts, with morphological traits consistent with Trypanoxyuris atelis and Trypanoxyuris atelophora. Phylogenetic analyses of 28S sequences corroborated species identities, suggesting minimal intraspecific divergence. In contrast, analysis of COI sequences revealed the existence of distinct lineages that paralleled host taxonomic identity for both pinworm species. Divergence levels remained below thresholds typical of species-level differentiation within the genus Trypanoxyuris, suggesting incomplete speciation following host diversification. These results echo those found in previous studies in other primate taxa and highlight the potential of pinworms as valuable indicators of host evolutionary and biogeographic histories. Our results reveal complex, species-specific evolutionary trajectories in Trypanoxyuris infecting spider monkeys and underscore the importance of comprehensive sampling for investigating parasite-host coevolution in platyrrhines.