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| Neacomys marci Brito & Tinoco, in Tinoco, Koch, Colmenares-Pinzón, Castellanos & Brito, 2023. |
Abstract
Neacomys is a genus of small spiny or bristly sigmodontine rodents that are common components of mammalian faunas in multiple biomes on Central and South America. Recent studies on this group have demonstrated that there is cryptic diversity yet to be discovered within currently recognized species that have not received comprehensive revisions, as well as in areas that have been overlooked. Here we ratify this assertion by describing a new species previously misidentified as the Narrow-footed Spiny Mouse (Neacomys tenuipes) from the Chocó biogeographic region in northwestern Ecuador, Neacomys marci Brito & Tinoco, sp. nov. Distinctiveness of this entity is supported by the combination of the following morphological characters: small size (head-body length 65–85 mm); long tail (69–126% longer than head-body length); pale buff-colored but gray-based belly fur; white throat; hypothenar pad usually absent; long nasals; and a condylar process higher than the coronoid process. Likewise genetic distance analyses and phylogenetic reconstructions based on cytochrome-b (Cytb) sequence data indicate a clear divergence from typical populations of N. tenuipes, and a sister relationship between them. The results presented here increase the diversity of Neacomys to 24 species, placing it among the most diverse genera within the sigmodontine rodents.
Key words: Chocó biogeographic, Neacomys tenuipes, premontane forest
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| Live specimen of Neacomys marci sp. nov. in its natural habitat (MECN 6230, Estación Fisher, Ecuador). Please note the color of a living animal. |
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| Ventral views of the skin of A Neacomys marci sp. nov. (MECN 6232, holotype; Estación Fisher, Ecuador), and B Neacomys tenuipes (UIS-MHN-M 1723; Finca La Bufalera, Colombia). Note the white-furred throat in N. marci sp. nov. (arrowed). |
Family Cricetidae Fisher, 1867
Subfamily Sigmodontinae Wagner, 1843
Tribe Oryzomyini Vorontsov, 1959
Genus Neacomys Thomas, 1959
Neacomys marci Brito & Tinoco, sp. nov.
Marc’s White-throated Spiny Mouse,
Ratón espinoso de Marc
Neacomys tenuipes: Brito et al. 2021a; Curay et al. 2022 (non Neacomys tenuipes Thomas, 1900).
Diagnosis: A species of Neacomys with the following combination of characters: small size (head-body length 65–85 mm), long tail (69–126% longer than head and body length), belly fur pale buff but with gray based hairs, white throat, long nasals (which extend well beyond the plane of the lacrimal), condylar process higher than coronoid process, M1 anterocone divided, M1 with broad protoflexus; m1–m3 with wide hypoflexids.
Etymology: Named in honor of Marc Hoogeslag of Amsterdam, the Netherlands. He was co-founder and leader of the innovative Land Acquisition Fund of the International Union for the Conservation of Nature - Netherlands, which helps local groups throughout the world to establish new ecological reserves and conserve endangered species. Fundacion EcoMinga’s Reserva Manduriacu, the habitat of this new species, is one of the many reserves which have benefited from Marc’s program. The species epithet is formed from the surname “Marc” taken as a noun in the genitive case, adding the Latin suffix “i” (ICZN 31.1.2).
Nicolás Tinoco, Claudia Koch, Javier E. Colmenares-Pinzón, Francisco X. Castellanos and Jorge Brito. 2023. New Species of the Spiny Mouse Genus Neacomys (Cricetidae, Sigmodontinae) from northwestern Ecuador. ZooKeys. 1175: 187-221. DOI: 10.3897/zookeys.1175.106113