This is the first installment of a revision of the didelphid marsupial genus Philander, commonly known as gray four-eyed opossums. Although abundant and widespread in lowland tropical forests from southern Mexico to northern Argentina, species of Philander are not well understood taxonomically, and the current literature includes many examples of conflicting species definitions and nomenclatural usage. Our revision is based on coalescent analyses of mitochondrial gene sequences, phylogenetic analyses of mitochondrial and nuclear genes, morphometric analyses, and firsthand examination of relevant type material. Based on these results, we provisionally recognize eight species, of which three are formally treated in this report: P. quica (Temminck, 1824), an Atlantic Forest endemic formerly known as P. frenatus (Olfers, 1818); P. canus (Osgood, 1913), a widespread species formerly treated as a synonym or subspecies of P. opossum (Linnaeus, 1758); and Philander pebas, a new species endemic to Amazonia. The remaining, possibly valid, species of Philander can be allocated to two clades. The first is a cis-Andean complex that includes P. andersoni (Osgood, 1913); P. mcilhennyi Gardner and Patton, 1972; and P. opossum. The second is a trans-Andean complex that includes P. melanurus (Thomas, 1899) and P. pallidus (Allen, 1901). Among other nomenclatural acts, we designate a neotype for the long-problematic nominal taxon Didelphis superciliaris Olfers, 1818, and (in an appendix coauthored by Renate Angermann), we establish that Olfers' coeval binomen D. frenata is based on an eastern Amazonian type and is a junior synonym of P. opossum.
The following accounts include an emended description of the genus Philander, redescriptions of P. quica and P. canus, and a description of our new Amazonian species, P. pebas. Additionally, these accounts serve to summarize geographic distributions, comment on relevant issues of nomenclature and identification, and list the morphological specimens we examined. Our abbreviated synonymies include only original descriptions (subsequent name combinations can be found in Patton and da Silva, 2008). Qualitative morphological comparisons of P. quica, P. canus, and P. pebas are summarized in table 6, and descriptive statistics are summarized in tables 7 and 8. Morphological comparisons with other species are restricted to members of the cis-Andean P. opossum complex.
Philander Brisson, 1762
Type Species: Didelphis opossum Linnaeus, 1758,
by plenary action of the International Commission on Zoological Nomenclature (ICZN, 1998).
Contents: Based on evidence summarized in this report, we tentatively recognize the following eight species as valid (synonyms in parentheses):
• andersoni Osgood, 1913;
• canus Osgood, 1913 (including crucialis Thomas, 1923; mondolfii Lew et al., 2006; and olrogi Flores et al., 2008);
• mcilhennyi Gardner and Patton, 1972;
• melanurus Thomas, 1899 (including fuscogriseus Allen, 1900; grisescens Allen, 1901; and melantho Thomas, 1923);
• opossum Linnaeus, 1758 (including frenatus Olfers, 1818; and superciliaris Olfers, 1818);
• pallidus Allen, 1901;
• pebas, new species (described below); and
• quica Temminck, 1824 (including azaricus Thomas, 1923).
In the absence of genetic information, we are currently unable to assess the validity of deltae Lew et al., 2006, and nigratus Thomas, 1923, either or both of which might also be good species.
Robert S. Voss, Juan F. Díaz-Nieto and Sharon A. Jansa. 2018. A Revision of Philander (Marsupialia: Didelphidae), Part 1: P. quica, P. canus, and A New Species from Amazonia. American Museum Novitates. Number 3891; 1-70. DOI: 10.1206/3891.1 digitallibrary.amnh.org/handle/2246/6839