Taxonomic reassessment of the chaco mice of the genus Andalgalomys Williams and Mares, 1978 (Rodentia, cricetidae) with a redefinition of Andalgalomys olrogi Williams and Mares, 1978

Abstract

The genus Andalgalomys Williams and Mares, 1978 includes three species of small phyllotine rodents: Andalgalomys olrogi Williams and Mares, 1978; Andalgalomys pearsoni (Myers, 1977); and Andalgalomys roigi Mares and Braun, 1996. These mice are distributed from southeastern Bolivia and western Paraguay to west-central Argentina, occupying mostly semi-desert environments, such as the Dry Chaco and High Monte. Available phylogenetic analysis of DNA sequences suggests that Andalgalomys olrogi and Andalgalomys roigi, which also share the same diploid complement, constitute the same species. We tested this hypothesis through a qualitative and quantitative morphological approach, in order to integrate different lines of evidence. Based on the largest sample analyzed to date, we found that some of the supposedly diagnostic traits of both Andalgalomys olrogi and Andalgalomys roigi (e.g., dorsal coloration) are more variable than previously documented. In addition, principal component analysis failed to separate Andalgalomys olrogi from Andalgalomys roigi in the multivariate space, although clearly segregate Andalgalomys pearsoni from these two taxa. Based on these findings, plus previous evidence, we consider Andalgalomys roigi as a junior synonym of Andalgalomys olrogi.