Historical Biogeography, Speciation, and Niche Evolution of Alouatta (Primates, Atelidae)

Aim

This study aims to evaluate the biogeographical and ecological patterns associated with the diversification and distribution of Alouatta species, commonly known as howler monkeys. Our research provides valuable insights into the comprehension of the evolutionary history of this genus.

Local

Neotropical region.

Time Period

Last 13 Mya.

Major Taxa Studied

11 species of Alouatta.

Methods

A dataset including 32 nuclear and mitochondrial genes was employed to reconstruct a dated maximum composite phylogenetic tree. Contemporary biodiversity data were employed in the context of this phylogenetic tree to reconstruct ancestral distribution and to infer the main speciation mechanisms. Niche evolution tests were performed for different bioclimatic and topographic variables to access patterns of niche divergence or niche conservatism.

Results

The diversification of Alouatta seems to have started ~13 Mya, probably near the Northwestern Amazon, and appears to have been driven mostly by niche divergence in parapatry. Despite this, niche conservatism or convergence led to significant overlap in ecological niches between some species, particularly those representing the early divergences of both South American clades.

Main Conclusions

The parapatric distribution presented by several pairs of Alouatta species generally evolved through environmental niche divergence driven by dispersal. The conservation or convergence of some niche traits is correlated with some secondary contacts, which may be increasing due to habitat loss. Niche conservation patterns found for some climatic variables highlight the susceptibility of the genus to climate change.