Aegialomys xanthaeolus (Cricetidae: Sigmodontinae) inhabits the arid montane areas of western Ecuador and Peru, and higher elevations in the upper Marañón valley in northern Peru. Some researchers have included this species in broader systematic assessments over the years, but there are no comprehensive studies focusing on intraspecific variation. There are several sources of intraspecific phenotypic variation, including sexual dimorphism and age. These sources may confound the assessment of similarity/dissimilarity among populations, therefore it is essential that non-geographic variation is evaluated before studies on geographical variation and species delimitation are carried out. Here we summarize existing information regarding the geographical... |