Systematics of <i>Marmosa</i> Subgenus <i>Micoureus</i> With Emphasis in ‘ <i>rapposa</i> ’ Group (Didelphidae, Marmosini): Geographic Variation and Revalidation of <i>M. budini</i>

ABSTRACT Micoureus is the most species‐rich subgenus within the genus Marmosa . Conflicting arrangements regarding the number of species comprising this subgenus have been proposed and the validity of M . budini has been debated. Here, we used an approach integrating genetic and morphological data were conducted to reanalyze the ‘ rapposa ’ group, investigate its biogeographic context, and test the status of M . budini as a distinct species of the M . rapposa complex. One mitochondrial and one nuclear marker were sequenced to recover species trees; divergence data and population aspects were inferred from mitochondrial data. Museum specimens were examined, including holotypes. The biogeographic data suggest the diversification in the ‘ rapposa ’ group to be associated with tectonism in the Andes and the Pebas System. Genetic analysis and external and craniodental morphology differences corroborate the species status of M . budini , with new record for Rondônia, Brazil, and M . rapposa would remain restricted to Peru. Marmosa rutteri exhibits intrapopulation variations driven by habitat fragmentation in the Pleistocene cycles and fluvial formations of the Amazon, and the separation in relation to M . budini coincides with climatic oscillations of the Late Quaternary and the Ucayali River.