Resumen

BRITO, Jorge et al. Unexpected diversity in the Andes of Ecuador: phylogeny of the Thomasomys “cinereus” group and description of a new species (Rodentia, Cricetidae). Mastozool. neotrop. [online]. 2019, vol.26, n.2, pp.308-330.  Epub 24-Sep-2019. ISSN 0327-9383.

Based on specimens collectedin the southeastern Andes of Ecuador, at Parque Nacional Sangay, but also including animals from mammal collections, a revision of the species of the group “cinereus” of the cricetid genus Thomasomys Coues, 1884 (Sigmodontini, Thomasomyini) was made. As a result, concomitantly to a new phylogeny based on a molecular marker (Cytb), a new species is recognized. It corresponds to a medium-sized Thomasomys which can be distinguished from the other species of the genus by the following traits: long tail, broad space between thenar and hypothenar pads, length of the maxillary toothrow < 5.6 mm, breadth of zygomatic plate < 2.9 mm, sphenopalatine vacuities as slits, posterior margin of nasals surpassing the level of the lacrimals, M1 with broad anteroloph and narrow mesoloph, M2 with short mesoloph, m1 with delicate mesolophid, and m2 with minute mesolophid. The new species of Thomasomys, at the moment endemic for the Parque Nacional Sangay, shows a genetic distance of 9.18% with respect to its sister species, T. caudivarius, which inhabits the southwestern Andes of Ecuador. With the reported finding, the richness of Thomasomysin Ecuador increases to 15 species, and rivals the one registered in Colombia. Finally, we pose the necessity to join efforts in order to produce a significant advance in the knowledge of this complex genus of Andean sigmodontines.

Palabras clave : Sangay National Park; Sigmodontinae; Thomasomyini; Thomasomys caudivarius; Thomasomys silvestris.