Coalescent-delimitation framework disentangles species boundaries within the Neotropical mouse-opossums subgenus <i>Marmosops</i>

Abstract The Neotropics encompasses a wide range of biomes and habitat types that place it as one of the most important regions for understanding the prevalence of cryptic and unknown diversity. However, this region is one of the least represented in genetic data in the tree of life. Therefore, advancing intra and interspecific genetic revisions in this region represents a major scientific priority to reduce our ignorance of the planet’s biodiversity. American marsupials of the subgenus Marmosops are distributed in a wide variety of Neotropical habitats, so it is an attractive group for undertaking studies on Neotropical diversification processes, but such research is hindered by the fact that we do not yet fully understand the species limits of some groups within the subgenus. Herein, we evaluate the evolutionary independence of 13 morphologically cryptic mtDNA haplogroups within Marmosops that were identified by our previous single-locus species delimitation analyses. For this purpose, we analyzed a multilocus dataset (12 unlinked nuclear loci and 1 mtDNA locus) in a Bayesian Multispecies Coalescent framework implemented in BPP—combined with heuristic criterion (gdi) that incorporated the speciation-continuum process into species delimitation analyses—to further understand genetic boundaries within this clade of Neotropical mouse-opossums. Our BPP analyses recovered each of the 13 haplogroups as independent evolutionary lineages. However, heuristic gdi showed that the tested lineages range across the entire spectrum of the speciation continuum, and that only 7 lineages recognized by BPP correspond to “true” species. Three of these 7 lineages are currently recognized as valid species, demonstrating the effectiveness of our study; while information on ecogeographic patterns revealed that the remaining 4 lineages have information that could lead to their eventual recognition as new species.