Descripción de una nueva especie de comadrejita ratona del género Marmosops Matschie, 1916 (Didelphimorphia, Didelphidae)

Abstract

Introduction: Within the genus Marmosops 17 species are currently recognized. Recent treatment of what has been recognized as the Marmosops parvidens group involves the recognition of five species: M. parvidens, M. pinheiroi [including woodalli], M. bishopi, M. juninensis, and M. pakaraimae. The two former and the last species occurs in Venezuela, being the identity of the single record of M. parvidens north of the Orinoco river placed in doubt by most recent authors.Methods: External measurements were taken from museum labels; craniodental measurements were taken with a caliper to the nearest 0.01mm. Geographic coordinates of relevant localities were taken from literature and altitudes from museum labels. Reviewed specimens (Apendix) are housed in: Museo de la Estación Biológica de Rancho Grande (EBRG, Aragua, Venezuela), Museo de Historia Natural La Salle (MHNLS, Distrito Capital, Venezuela), Museo de Zoología de la Universidad de Carabobo (MZUC, Carabobo, Venezuela) and Colecão Zoológica de Mastozoología, Universidad Federal de Mato Grosso (UFMT, Cuiabá, Mato Grosso, Brazil). Relevant characters of taxa unavailable to us were taken from literature.Results: Recently additional material assignable to Marmosops parvidens from northern Venezuela was analyzed. Closer examination of these specimens led to the description of a new species herein proposed, which is clearly distinguished from other species of the group by a unique combination of characters, among them, a triangle-shaped carpal tubercle in males; posterior accessory cusps on the upper canines in males and females; maxilla not completely covering the fourth upper molar, and fourth lower molar bicuspid (Table 2; Fig. 2, 3, 4 and 5). Known distribution embraces the Cordillera de la Costa Central and Cordillera de Mérida in Venezuela (Fig. 1), with an elevation span of 50 to 1850 m a.s.l.Discussion and Conclusions: Before the recognition of Marmosops pinheiroi as a distinct species, many authors accepted the presence of M. p. parvidens in northern Venezuela and south of the river Orinoco (Amazonas) and M. p. pinheiroi in the south (Bolívar, Canaima National Park). More recently, the presence of parvidens was referred to the north and south of Venezuela and in sympatry with M. pinheiroi at Canaima National Park. However, examination of the specimens of Marmosops housed in Venezuelan natural history museums indicates that M. parvidens is not present in Venezuela (pending the confirmation of the identity of a single specimen from northern Venezuela housed in Washington). Equally, literature records might be misleading (e. g. the sympatry of M. parvidens and M. pinheiroi at Canaima National Park). So far, records of the new species indicate it is restricted to the mountain ranges of northern and western Venezuela.Key words: Cordillera de la Costa Central, Cordillera de Mérida, marsupials, taxonomy, Venezuela.