Research paper Molecular systematics of the genus Necromys (Rodentia: Cricetidae: Sigmodontinae) reveals two cryptic and syntopic species in western Cerrado of Brazil Alexandra Maria Ramos Bezerra a, b, * , Riccardo Castiglia c , Luciana Guedes Pereira d , J ^ anio Cordeiro Moreira e, f , Cibele Rodrigues Bonvicino b, g a Mastozoologia/COZOO, Museu Paraense Emilio Goeldi, Campus de Pesquisa, Av. Perimetral 1901, CEP 66077-830, Bel em, PA, Brazil b Laborat orio de Biologia e Parasitologia de Mamíferos Silvestres Reservat orios, Instituto Oswaldo Cruz, Fiocruz, Av. Brasil, 4365, CEP 21045-900, Rio de Janeiro, RJ, Brazil c Dipartimento di Biologia e Biotecnologie ‘Charles Darwin’, Universit a di Roma ‘La Sapienza’, via A. Borelli 50, CAP 00151, Rome, Italy d Instituto de Biologia, Universidade do Estado do Rio de Janeiro, CEP 20550-900, RJ, Brazil e Laborat orio de Biologia Animal, Instituto Federal Goiano, Campus Rio Verde, Rio Verde, Caixa Postal 66, CEP 75901-970, GO, Brazil f Programa de P os-Graduaç~ ao em Biodiversidade e Biologia Evolutiva, Instituto de Biologia, Universidade Federal do Rio de Janeiro, CEP 21941-590, RJ, Brazil g Divis~ ao de Gen etica, Instituto Nacional de C^ ancer, Rua Andr e Cavalcanti, 37, 4  andar, CEP 20231-050, Rio de Janeiro, RJ, Brazil article info Article history: Received 4 May 2019 Received in revised form 14 February 2020 Accepted 24 February 2020 Available online 29 February 2020 Corresponding Editor: J Ziermann Keywords: Cytochrome-b Holotypes Nasal bones Necromys lasiurus Necromys lenguarum Zoonosis abstract Necromys is a genus of sigmodontine rodent widely distributed throughout South America, from central Argentina to Trinidad and Tobago, and includes eight living species. In Brazil, two species are currently known: Necromys lasiurus, widely distributed, and Necromys lenguarum, known only from a sole locality in Mato Grosso state, core area of Cerrado domain, based on its putative junior synonymy, Zygodontomys tapirapoanus. The latter species have been previously recorded in Bolivia, Paraguay, Argentina, and Peru, but many authors did not acknowledge the presence of the species in Brazil. Based on molecular data (mitochondrial gene Cytochrome b), we present five new localities of the here recognized N. lenguarum, along with new samples of N. lasiurus from sympatric and parapatric localities. Voucher specimens of N. lasiurus and N. lenguarum had their identification confirmed by molecular data, followed by morphological comparison with representatives of other Necromys species, including type specimens. These results prompted new insights into morphology and geographic distribution of N. lenguarum, and revealed that the characters currently proposed as diagnostic for N. lenguarum failed to distinguish it from the N. lasiurus (Lund, 1840). Since that we found syntopy of the two species and the type locality of N. lenguarum fall within the distribution range of N. lasiurus sequenced specimens, in absence of DNA sequence of the N. lenguarum holotype, the taxonomic identity of populations until now referred to N. lenguarum still require further analyses including DNA sequence from its holotype. Furthermore, both species are involved in distinctive zoonotic cycles and were found in syntopy in a new locality, high- lighting the importance of better delimitate cryptic species. © 2020 Elsevier GmbH. All rights reserved. 1. Introduction Hairy-tailed bolo mouse rodents of the genus Necromys Ame- ghino, 1889 comprise eight currently recognized extant Cricetidae species (Pardi ~ nas et al. 2015; Jayat et al. 2016): Necromys obscurus (Waterhouse, 1837), Necromys lasiurus (Lund, 1840), Necromys punctulatus (Thomas, 1894), Necromys urichi (Allen & Chapman, 1897), Necromys lenguarum (Thomas, 1898), Necromys amoenus (Thomas, 1900), Necromys lactens (Thomas, 1918), and Necromys lilloi Jayat, D’Elía, Ortiz & Teta, 2016. The genus is widely distributed mainly throughout a variety of open area environments of South America, from central Argentina to Trinidad and Tobago (Pardi ~ nas et al. 2015). In Brazil, two species, N. lasiurus and N. lenguarum, have been reported; they occur in neighbor localities, so that sympatry is expected for these species (Pardi ~ nas et al. 2015). The * Corresponding author. Mastozoologia/COZOO, Museu Paraense Emilio Goeldi, Campus de Pesquisa, Av. Perimetral 1901, CEP 66077-830, Bel em, PA, Brazil. E-mail address: amrbezerra@hotmail.com (A.M.R. Bezerra). Contents lists available at ScienceDirect Zoologischer Anzeiger journal homepage: www.elsevier.com/locate/jcz https://doi.org/10.1016/j.jcz.2020.02.007 0044-5231/© 2020 Elsevier GmbH. All rights reserved. Zoologischer Anzeiger 285 (2020) 147e158