Changing Only Slowly: The Role of Phylogenetic Niche Conservatism in Caviidae (Rodentia) Speciation

Abstract

The dynamics of species diversification have attracted significant scientific attention in recent decades. Many lineages tend tomaintain their niche characteristics over evolutionary time, a phenomenon known as phylogenetic niche conservatism (NC),which can slow the processes of ecological speciation by diversification selection. NC can, however, promote speciation throughneutral evolution, favoring the geographic isolation of populations. Among the mega-diverse Rodentia group, the low speciesrichness of the family Caviidae stands out. Here, we analyzed if the processes of climatic NC are related to the slow diversificationobserved in the Caviidae family. Locality data for 13 species and nine climatic variables were used to generate ecologicalniche models. Niche similarity was quantified using the Schoener D index and used to examine correlations between the times ofspecies divergence and niche similarities, thus characterizing their niche occupation profiles (NOP). The NOP were subsequentlyused to perform phylogenetic niche reconstructions for these species. Niche models accurately described known distributions ofspecies. The greatest niche overlap documented was between Kerodon rupestris and Galea spixii (0.86). The niche and speciesdivergence times showed a negative correlation (beta = -0.013; p = 0.01). These results support the existence of NC, withphylogenetically closer species occupying similar niches, and emphasize the importance of NC in diversification processes atcontinental scales in a slowly diversifying group.