Nephelomys albigularis is a sigmodontine rodent of the tribe Oryzomyini distributed in the Andean forests from central Ecuador to central Peru. Although several studies recognize this species as monotypic, significant morphological variation has been reported in Peruvian populations that were not properly assessed by direct comparisons with the type series from central Ecuador. We present a preliminary review of N. albigularis with an integrative approach and emphasis on Peruvian populations. We analyzed specimens using morphological and morphometric methods, complemented with phylogenetic analyses and species delimitation using sequence data from the cytochrome-b gene. Our results reveal that N. albigularis (sensu lato) comprises two taxa: N. albigularis s.s., from the montane forests in central and southern Ecuador and northwestern Peru, and Nephelomys sp. nov. from montane forest east of the Marañón River. These taxa are morphologically distinct and are separated by a genetic distance of 5.90 ± 1.01%. Nephelomys sp. nov. differs from N. albigularis s.s. by longer rump hairs, narrow hypothenar pads, faintly bicolor tail; absent interorbital ridges, low zygomatic plates, smoothly squared posterior margin of the hard palate or with a small median postpalatal process, smoothly edged ventral margin of the external auditory meatus, and slightly angular mandibular sigmoid notches. In this work, we present a diagnosis and description of the new species of Nephelomys and discuss the role of the Marañón River as a potential driver for speciation in the genus Nephelomys.
Bibliographical noteFunding Information:
We thank Luz Segura, Mercedes Molina, Miluska Sánchez, Isabel Centeno, Maribel Taco, Rocío Bardales, Luis Moreno, Nadia Espinoza, Raisa Cairampoma, and Pilar Herrera for assisting during fieldwork, and to senior collectors that obtained many of the specimens of Nephelomys in MUSM collection, including Elena Vivar, Richard Cadenillas, Carlos Tello, Heidi Quintana, Alicia Vásquez, and Edith Salas. We thank José La Torre for allowing us to collect in the Area de Conservación Privada Huiquilla. We thank SERFOR for the research permit Resolución de Dirección General N°115-2016-SERFOR/DGGSPFFS. We also thank Jorge Brito for allowing us access to the In-stituto Nacional de Biodiversidad collection, Bruce Patterson (Field Museum of Natural History, Chicago), and Roberto Portela and the Picture Library of the Natural History Museum, London for sharing photos of the type series of Hesperomys albigularis. We thank Ulyses Pardiñas (Centro Nacional Patagónico, Chubut) for his comments on this manuscript. Finally, we thank the two reviewers who helped improve this manuscript. This study was partially funded by INNOVATE Peru by Contract N°402-PNICP-PIBA-2014. This work was made under the objectives of the DIMAPA research group of the Vicerrectorado de Investigación y Posgrado of the UNMSM.
© 2021 Magnolia Press.
- Huancabamba depression
- Marañón River
- Mountain forests