Late Pleistocene Altitudinal Segregation and Demography Define Future Climate Change Distribution of the Peromyscus mexicanus Species Group: Conservation Implications.

Mountains harbor a significant number of the World's biodiversity, both on tropical and temperate regions. Notably, one crucial gap in conservation is the consideration of historical and contemporary patterns influencing differential distribution in small mammal mountain species and how climate change will affect their distribution and survival. The mice Peromyscus mexicanus species group is distributed across mountains in Guatemala-Chiapas and Central America, which experienced significant effects of glacial and interglacial cycles. We determined phylogeographic and demographic patterns of lowlands and highlands mountain lineages, revealing that the radiation of modern P. mexicanus lineages occurred during the Pleistocene (ca. 2.6 mya) along Nuclear Central America. In concert with climatic cycles and the distribution of habitats, lowland and highland lineages showed recent population size increase and decrease, respectively. We also estimated the current and future distribution ranges for six lineages, finding marked area size increase for two lineages for which vegetation type and distribution would facilitate migrating towards higher elevations. Contrastingly, three lineages showed range size decrease; their ecological requirements make them highly susceptible to future habitat loss. Our findings are clear evidence of the negative impacts of future climate change, while our ability to manage and conserve these vulnerable ecosystems and mountain species is contingent on our understanding of the implications of climate change on the distribution, ecology, and genetics of wildlife populations.

A new species of long-tailed shrew of the genus Sorex (Eulipotyphla: Soricidae) from Sierra de Omoa, Honduras.

The only known species of the genus Sorex in Honduras is Sorex mccarthyi Matson Ordóñez-Garza, which is endemic to Celaque National Park. This species shows the presence of a postmandibular foramen and canal, a characteristic that is useful to distinguish between species south of the Isthmus of Tehuantepec and unique to the Sorex salvini species group. Recently, two specimens of Sorex were collected in 2018 at Cusuco National Park, northwestern Honduras. These specimens lack the distinctive characteristics possessed by the S. salvini species group and belong to the Sorex veraepacis species group. Previously, the S. veraepacis species group was only known from the highlands of the southern Mexican state of Chiapas and Guatemala. Principal component analysis shows that specimens from Sierra de Omoa are different in size and shape with respect to other known species (i.e., S. veraepacis Alston, S. ibarrai Matson McCarthy and S. madrensis Matson Ordóñez-Garza). We describe these two specimens, currently known only from an isolated cloud forest in the Sierra de Omoa, Honduras, as a new species.