Molecular phylogenetics of an endangered species: the Tamaulipan woodrat (Neotoma angustapalata)

Abstract

Neotoma angustapalata (Tamaulipan woodrat) is a large cricetid rodent found only in southwestern Tamaulipas and northeastern San Luis Potosi, Mexico. This species currently is listed as endangered due to habitat alteration, its restricted distribution, and relative rarity. Previous taxonomic assessments have allied N. angustapalata with N. albigula (now encompassing N. leucodon), N. mexicana or N. micropus. We sequenced portions of the mitochondrial cytochrome b gene from two skin samples of the Tamaulipan woodrat, including one of two topotypes. We estimated genealogical relationships between N. angustapalata and other species of Neotoma using maximum likelihood and Bayesian inference. In general, our results confirm the phylogeny of woodrats as proposed previously but we also recovered major genetic differentiation within what currently is recognized as N. mexicana and N. albigula. Our data document that the Tamaulipan woodrat is genetically indistinguishable from geographically adjacent haplotypes of N. leucodon. However, mitochondrial introgression from N. leucodon cannot be ruled out inasmuch as we were not able to obtain nuclear sequence data for N. angustapalata. Morphological analyses document that both male and female Tamaulipan woodrats differ morphologically from N. leucodon. Given that the Tamaulipan woodrat is diagnosable morphologically and occurs in habitat that differs from N. leucodon, we recognize N. angustapalata as a species-level entity.