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Speciation and gene flow in two sympatric small mammals from Madagascar, Microgale fotsifotsy and M. soricoides (Mammalia: Tenrecidae)

Citation

Everson, Kathryn M; Olson, Link E; Goodman, Steven M (2020), Speciation and gene flow in two sympatric small mammals from Madagascar, Microgale fotsifotsy and M. soricoides (Mammalia: Tenrecidae), Dryad, Dataset, https://doi.org/10.5061/dryad.9p8cz8wc1

Abstract

Madagascar’s shrew tenrecs (Mammalia: Tenrecidae: Microgale, Nesogale) form an excellent system for studying speciation. Most species are endemic to the island’s eastern moist evergreen forest, a region renowned for high levels of biodiversity and a high rate of in situ diversification. We set out to understand the speciation dynamics in a clade of recently described taxa: Microgale fotsifotsy and M. soricoides, which have nearly identical distributions in the moist evergreen forest, and M. nasoloi, which occurs in the western dry deciduous forest. A phylogenetic analysis using mitochondrial DNA data recovered two distinct clades of M. fotsifotsy: a south clade that is sister to M. soricoides, and a north clade that is sister to the dry-forest species M. nasoloi. To better understand this result, we analyzed cranioskeletal measurements and performed demographic analyses using nuclear sequence data from ultraconserved elements. Nuclear data found M. fotsifotsy to be monophyletic, but demonstrated that gene flow is absent between the north and south clades. The same analyses also recovered introgression between M. soricoides and the south clade of M. fotsifotsy, which helps to explain the disagreement between the mitochondrial and nuclear phylogenies. Morphometric data revealed several major differences between M. soricoides and M. fotsifotsy, as well as more subtle differences between the two clades of M. fotsifotsy. Our findings demonstrate that the use of multiple datasets to understand speciation history, and contribute to a growing body of evidence that far-northern Madagascar is an important region of microendemism.

Funding

National Science Foundation, Award: DEB-1120904