A hint on the unknown diversity of eastern Andes: high endemicity and new species of mammals revealed through DNA barcoding

Abstract

The eastern Andean slopes harbours a diverse fauna with multiple endemic and endangered species. The region is identified as a biodiversity hotspot with high conservation priority. However, it remains one of the least studied in South America regarding the diversity of mammals. Here we present new data on the diversity of non-volant small mammals (marsupials and rodents) from Parque Nacional del Río Abiseo (PNRA), a poorly known, remote site located in the eastern Andean slopes in central-northern Peru. We sequenced the mitochondrial gene cytochrome b to provide identification of the collected specimens, and to discuss zoogeographic patterns of the species from PNRA and closely related taxa. In 15 days of sampling at PRNA we registered 16 species (12 rodents, 4 marsupials) on montane forests between 2500 and 2800 m above sea level (asl). Combined with results from previous surveys, the diversity of non-volant small mammals at PNRA (23 species) is the highest ever recorded for high Andes. Remarkably, only four of the 16 species recorded in our expedition could be assigned to described species based on molecular identification. The remaining 12 species need urgent taxonomic attention, several of which are potentially new to science. Moreover, 11 of the 16 species (69%) registered are currently unknown from other sites, suggesting a large beta diversity. A combination of exceptional levels of endemism in Andean montane forests and an obvious sampling bias resultant of the lack of comprehensive surveys explain the high number of ‘unique’ species at PNRA. Our phylogenetic analyses suggest that the non-volant small mammals from PNRA seem to have diverse phylogeographic affinities, with a closer proximity with central Andes. The scarcity of sequenced samples for comparative analyses from multiple Andean sites is, however, a major barrier to the development of accurate historical reconstructions for these endemic faunas.

Key words:

• Didelphimorphia
• faunal survey
• Montane forests
• non-volant small mammals
• Peru
• Rodentia
• Yungas

Acknowledgments

The expedition to Parque Nacional del Río Abiseo was only possible due to support provided by National Geographic Society through an Explorers Grant (NGS-381R-18). We are particularly grateful to F. Câmara, as well as park personnel from PNRA and the inhabitants of Pataz and Los Alisos for their crucial help during fieldwork. We thank L. Cayo from SERFOR, for her valuable advice and orientation regarding permits to access genetic resources, and SERNAMP for facilitating collection permits and access to the PNRA. We are indebted to R. Voss, J. Maldonado, L. Emmons, and M. McGowen, who provided support and shared precious insights that inspired us to apply for funding to pursue this project.

SEP was supported by grants from Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq, Brazil), and the Oliver P. Pearson award from the American Society of Mammalogists. EFA was supported by grants from CNPq (147145/2016-3, 203692/2017-9, and 165553/2017-0) and the Richard Gilder Graduate School of the American Museum of Natural History (Gerstner Scholar Postdoctoral Fellowship). RB was supported by resources from the FINEp grant ‘Parque analítico do MPEG: análise das transformações da Amazônia e seus reflexos na sociobiodiversidade e na paisagem’ (01.18.0031-00), the Natural Environment Research Council (NERC NE/T000341/1), and FAPEAM (01.02.016301.01763/2021). PP was supported by grants from CNPq and an award from the Maxwell/Hanrahan Foundation.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplemental material

Supplemental material for this article can be accessed here: https://dx.doi.org/10.1080/14772000.2024.2302196

Associate Editor: Dr Peter D. Olson

Notes

1 Although the total number of specimens registered in La Playa + Las Papayas equals to 309, we excluded 31 records of “Nephelomys spp.” and computed the R/E abundance curves with the remaining 278 records. The 31 records excluded correspond to the specimens of Nephelomys released in the field, that could only be confidently identified to the genus level and therefore could not be included on the R/E abundance curves.

Additional information

Funding

This work was supported by the National Geographic Society under Grant [NGS-381R-18].