Differential climatic niche diversification processes in South American rodents (Octodontoidea) across tropical and extratropical regions

Abstract

1. Studying niche evolution becomes central to understanding the processesdriving species diversification along latitudinal gradients. Octodontoidea rodentsserve as a model group for understanding how the colonisation of extratropicalregions has shaped the climatic niche evolution of species.2. We analyse the time and mode of climatic niche evolution among differentOctodontoidea lineages to understand how niche evolutionary processes operateacross the spatial gradient of the Neotropical region.3. We constructed ecological niche models for living Octodontoidea species toassess the timing and mode of climatic niche evolution across tropical andextratropical lineages. We estimated niche similarity and correlated it withspecies divergence times, and estimated the rate of climatic niche diversificationacross lineages.4. Our results show a trend of greater niche overlap in more recent lineagesand lower niche overlap in older lineages. However, extratropical lineagesexhibit lower climatic niche overlaps. From diversification analysis, we detectedthat the Ctenomyidae group shows higher rates of niche diversification, whereasthe tropical Echimyidae group exhibits the lowest rates of climatic nichediversification.5. Our results support the idea that the lineages restricted to tropical regionstend towards niche conservatism. However, some tropical lineages have successfullycolonised extratropical regions, and this colonisation has been accompaniedby strong selective pressures, leading to higher rates of nichediversification and lower climatic niche overlap among species.