Phylogenetic relationships of Mesoamerican spider monkeys (Ateles geoffroyi): Molecular evidence suggests the need for a revised taxonomy.

Mesoamerican spider monkeys (Ateles geoffroyi sensu lato) are widely distributed from Mexico to northern Colombia. This group of primates includes many allopatric forms with morphologically distinct pelage color and patterning, but its taxonomy and phylogenetic history are poorly understood. We explored the genetic relationships among the different forms of Mesoamerican spider monkeys using mtDNA sequence data, and we offer a new hypothesis for the evolutionary history of the group. We collected up to ∼800 bp of DNA sequence data from hypervariable region 1 (HV1) of the control region, or D-loop, of the mitochondrion for multiple putative subspecies of Ateles geoffroyi sensu lato. Both maximum likelihood and Bayesian reconstructions, using Ateles paniscus as an outgroup, showed that (1) A. fusciceps and A. geoffroyi form two different monophyletic groups and (2) currently recognized subspecies of A. geoffroyi are not monophyletic. Within A. geoffroyi, our phylogenetic analysis revealed little concordance between any of the classifications proposed for this taxon and their phylogenetic relationships, therefore a new classification is needed for this group. Several possible clades with recent divergence times (1.7-0.8 Ma) were identified within Ateles geoffroyi sensu lato. Some previously recognized taxa were not separated by our data (e.g., A. g. vellerosus and A. g. yucatanensis), while one distinct clade had never been described as a different evolutionary unit based on pelage or geography (Ateles geoffroyi ssp. indet. from El Salvador). Based on well-supported phylogenetic relationships, our results challenge previous taxonomic arrangements for Mesoamerican spider monkeys. We suggest a revised arrangement based on our data and call for a thorough taxonomic revision of this group.

Revisiting the phylogenetic relationships, biogeography, and taxonomy of spider monkeys (genus Ateles) in light of new molecular data.

Spider monkeys (Ateles) are one of the most endangered groups of primates in the Neotropics. The genus is widely distributed from Mexico to the north of Bolivia and includes many morphologically distinct forms in terms of pelage color and patterning. The taxonomy, phylogenetic relationships, and biogeographic history of the genus have been subject to much debate, making scientific communication difficult and creating challenges for conservation actions. We extracted DNA from samples of all currently recognized species of spider monkeys collected from across the geographic range of the genus, sequenced ∼3.5 kilobases of coding sequence from the mitochondrial genome, and used this large dataset to (a) infer the phylogenetic relationships among the different forms of spider monkeys, (b) evaluate whether currently recognized species of spider monkeys form reciprocally monophyletic groups that are concordant with contemporary classifications, and (c) estimate divergence dates among the different lineages of Ateles. We found that all proposed species of spider monkeys for which we have samples from multiple localities indeed appear to form monophyletic groups. However, in contrast to previous studies, several of our analyses robustly inferred Ateles marginatus from northeast Brazil as the sister taxon to all other spider monkeys. A Bayesian dating analysis suggests that the most recent common ancestor of extant Ateles dates to ∼6.7 Ma, in the late Miocene, and most species-level splits within the genus took place in the late Pliocene, suggesting that the modern diversity in spider monkeys cannot be explained principally by isolation and divergence of populations in forest refugia during the Pleistocene. Based on our new phylogenetic inference and dating analysis, we propose a revised biogeographic scenario for the evolution of this genus.