Soft anatomy and morphological variation in <i>Daptomys peruviensis</i> (Rodentia, Cricetidae), a rare ichthyomyine from the northwestern Amazonian forests

The recently resurrected genus <i>Daptomys</i> Anthony, 1929 includes poorly known small cricetid rodents that are widely distributed in tropical South America. Along with <i>Neusticomys</i> Anthony, 1921, these species are the most terrestrial members of the tribe, which is otherwise distinguished by adaptations that allow species to live in both aquatic and terrestrial environments. Newly collected Ecuadorean specimens provide complementary information of the craniodental and soft anatomy of <i>Daptomys</i>, focusing on rhinarium morphology, soft palate, stomach, caecum configuration, and other features. In addition, the phylogeny presented here, combined with species distribution models, suggests a simplified taxonomy indicating that <i>Daptomys peruviensis</i> (Musser & Gardner, 1974) has a wide distribution extending from Venezuela to Peru. In this novel scenario, <i>Daptomys mussoi</i> (Ochoa & Soriano, 1991) would be a junior synonym of <i>D. peruviensis</i>, and the application of a trinominal taxonomy appears premature.