Two new species of Philander (Didelphimorphia, Didelphidae) from northern South America

The taxonomy of gray four-eyed opossums, genus Philander, from northern South America is reviewed by means of comparative morphological and morphometric analyses. Two hundred eighteen specimens belonging to the following geographic samples were used: P. opossum opossum from French Guiana, Guyana, and Suriname; P. o. fuscogriseus from Central America and Colombia; P. andersoni from Colombia, Ecuador, Peru, and Venezuela; P. opossum from the Orinoco River delta (Venezuela); P. opossum from western Venezuela and eastern Colombia; and P. opossum from central Venezuela. Results obtained allow us to describe 2 new Philander species, one of which occurs in the floodplains of the Orinoco River delta and Paria Gulf (Venezuela), and the other of which is distributed in lowlands and uplands at the northern border of the Guiana Shield in Venezuela, as far as the Orinoco River, and foothills of Cordillera Oriental (Colombia) and Cordillera of Merida (Venezuela). These new taxa were formerly considered to represent forms of P. opossum. In particular, it was suggested that specimens from the Orinoco delta constituted a subspecies of P. opossum, but this taxonomic pattern was not supported with detailed comparative analyses. Furthermore, the subspecific status of animals from western Venezuela and eastern Colombia was controversial and specimens from central Venezuela were considered as P. opossum but no empirical data supported this taxonomic identity. With respect to the other Philander species here considered, the 1st new species clearly differs in features concerning general skull shape and morphology, by its smaller skull size, relatively shorter tail, presence of a wide gray area in the underparts of the coat, and smaller and poorly defined supraorbital spots. The 2nd new species can be distinguished from the other Philander taxa by the general skull shape (relatively wide and short), specific skull traits, pale gray dorsum, and the characteristic coloration of ears (white with a wide black margin).