Abstract Ecological niche conservatism and divergence are key indicators of diversification and speciation processes. Niche conservatism often indicates allopatric speciation, where geographical barriers separate populations, while divergence typically arises when ecological adaptations promote reproductive isolation and speciation. Diversification in the nocturnal primate family Galagidae of mainland sub-Saharan Africa has been hypothesized to have been driven by adaptational changes or climate change-induced allopatry. However, few studies have characterized ecological niche-based characteristics to validate these hypotheses. We constructed ecological niche models using bioclimatic variables and the Maxent distribution modelling algorithm for sister species within the nocturnal primate family Galagidae. We assessed niche separation with principal component analyses, equivalency, and similarity analyses. Sister species in Galago and Euoticus exhibited non-equivalent niches, whereas Otolemur and Paragalago species exhibited equivalent niches. Niches for Paragalago sister species were more similar than expected. Range overlap was unrelated to niche overlap. These results indicate limited but mixed roles for ecological niche divergence and adaptations in family-wide diversification. Divergence in Euoticus is especially intriguing, potentially pointing to unique adaptational diversification processes in the Gulf of Guinea rainforests. Future research should examine alternative mechanisms for speciation in this group and explore regional diversification patterns in greater detail.
Miller et al. (Tue,) studied this question.