Three new species of spiny mice, genus Neacomys Thomas, 1900 (Rodentia: Cricetidae), from Brazilian Amazonia

Abstract

Spiny mice of the genus Neacomys Thomas, 1900 are small oryzomyines that occur in forested habitats from Panama to central Bolivia. Previously known by only four species, systematic revisions provided great increase in genus species richness, which currently comprises 20 valid species. Herein we raise this number to 23, describing three new species of spiny mice. The new taxa are found in western and central Brazilian Amazonia in the states of Amazonas and Pará, and their geographic distribution are delimited by major rivers, being coincident with previously described Amazonian centers of endemism: (1) Neacomys aletheia, sp. nov., ranging from the right and left bank of the Rio Juruá, Amazonas state, Brazil to Loreto in Peru, from the Inambari center; (2) Neacomys jau, sp. nov., distributed between the Rio Negro and Rio Solimões, Amazonas state, Brazil, from the Imeri center; and (3) Neacomys elieceri, sp. nov., restricted to the Rondônia endemism center, between the Rio Tapajós and Rio Madeira, Pará state, Brazil. Previously reported more than 20 years ago as putative new species based on molecular and cytogenetic data, morphological analyses now reinforce the validity of these forms. Based on the analysis of 78 specimens, including name-bearing types from most of the distributional range of Neacomys, we formally describe and name these undescribed species. The new taxa can be distinguished from other closely related Neacomys by a set of qualitative traits, such as dorsal and ventral pelage coloration, tail color, morphology of the nasal bones, interorbital region, paraoccipital process, sphenopalatine foramen, incisive foramina, zygomatic plate, auditory bullae, foramen accessorius, anterocone and anteroloph of first upper molars, in association with cytochrome b gene sequences, and karyotype. These data increase the currently known Neacomys diversity, and also contribute to elevate Amazonian sigmodontinae species richness and endemism, in this yet poorly surveyed biome.

urn:lsid:zoobank.org:pub:1721BB20-3542-4959-B95E-A36B0D522F39

Key words:

• Amazonia
• Cricetidae
• Neacomys
• Rodentia
• sigmodontinae
• spiny mice

Acknowledgements

We are grateful to the following curators and collection managers for permitting access to specimens under their care: Robert Voss and Eileen Westwig (AMNH), Roberto Portella (BMNH), John R. Wible and Susan B. McLaren (CM), Suely Marques-Aguiar (MPEG), Luis Fabio Silveira and Juliana Gualda (MZUSP), Christiane Denys (MNHN), Burton Lim (ROM), Ana Cristina Mendes Oliveira (UFPA), Priscilla Tucker and Cody Thompson (UMMZ), Kris Helgen and Darrin Lunde (USNM). We thank Jose Ochoa for kindly providing the Fig. 9; Dr. Guilherme Garbino and Dr. Aldo Caccavo for reading a previous version of the manuscript; and Dr. Pablo Teta, an associate editor and one anonymous reviewer who made several helpful suggestions for the manuscript. We also thank Caroline Tocchet, Gustavo Libardi, José Nascimento, Marcus Brandão, Rafael Mendonça, Raphaella Coutinho, Victor Colombi and Yolanda Salgueiro for aiding in the Juruti field trips for mammalian survey; Laboratório de Scarabaeoidologia at Universidade Federal de Mato Grosso (Cuiabá, Mato Grosso, Brazil), which provided access to the equipment used to make Figs 5–7, obtained as part of the subproject EECBio of UFMT/FINEP (agreement FINEP # 01.12.0359.00), and Vinícius Costa-Silva for helping to obtain the photos; and Georgia Frangou for her counsel with the Greek language.

Disclosure statement

The authors declare no conflicts of interest.

Supplementary material

Supplementary material for this article can be accessed here: https://doi.org/10.1080/14772000.2021.1980449.

Associate Editor: Susan Tsang

Additional information

Funding

This work was partially supported by Fundação de Amparo à Pesquisa do Estado de Mato Grosso (FAPEMAT/PRONEM #477017/2011 to R.V.R); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) - Finance Code 001; Ernst Mayr Grant from the Museum of Comparative Zoology at Harvard University, Cambridge, MA; Small grants from the American Museum of Natural History (New York); Muséum d’Histoire Naturelle (Geneva); Programa de Pós-Graduação em Zoologia da Universidade Federal de Mato Grosso (PPGZOO/UFMT); and by scholarships from Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) and Ministério da Ciência, Tecnologia, Inovações e Comunicações (MCTIC) (301208/2021-2).