Marmosa (Marmosa) waterhousei (Tomes, 1860)

Voss, Robert S., 2022, An Annotated Checklist Of Recent Opossums (Mammalia: Didelphidae), Bulletin of the American Museum of Natural History 2022 (455), pp. 1-77 : 15

Marmosa (Marmosa) waterhousei

( Tomes, 1860)

TYPE MATERIAL AND TYPE LOCALITY: BMNH 7.1 .1.215, the lectotype (designated by Thomas, 1921a), consists of a skull, said to be that of an adult female, collected at Gualaquiza (3.40° S, 78.55° W; 914 m), Morona-Santiago province, Ecuador. The rest of the specimen, originally preserved in fluid, has been lost. 5 Jenkins and Knutson (1983) referred to this specimen as the holotype, but Tomes’ (1860) description was based on an adult and an unspecified number of young individuals, all of which were, in effect, syntypes .

SYNONYMS: bombascarae Anthony, 1922; maranii Thomas, 1924.

DISTRIBUTION: As currently recognized, Marmosa waterhousei occurs in the lowlands and adjacent Andean foothills of southeastern Colombia, eastern Ecuador, northeastern Peru (north of the Amazon), and a few scattered localities in the Andes of northern Colombia and western Venezuela ( Gutiérrez et al., 2011: fig. 2). A recently published Peruvian record from south of the Amazon (in Junín department; Pacheco et al., 2020) merits phenotypic and genetic confirmation.

REMARKS: Marmosa waterhousei was ranked as a subspecies of M. murina by Tate (1933), and it was treated as a synonym of M. murina by Creighton and Gardner (2008a). Current recognition of M. waterhousei as a valid species follows Rossi (2005), who provided a morphological description, tabulated measurement data, and carried out morphometric comparisons with other congeners. Despite compelling support for currently recognized species limits in the subgenus Marmosa from phylogenetic analyses of

5 Tomes’ (1860) assertion that the fluid-preserved type of Marmosa waterhousei had a pouch is impossible to reconcile with its skull, which clearly belongs to a species in the pouchless nominotypical subgenus of Marmosa . However, the application of this name can only be based on what remains of the specimen, and on the type locality (eastern Ecuador), where only a single species of the nominotypical subgenus is known to occur.

DNA sequence data ( Gutiérrez et al., 2010; Voss et al., 2014), morphological distinctions between some pairs of species remain problematic. Apparently, only measurement data seem to consistently distinguish specimens of M. waterhousei from specimens of M. macrotarsus (see Voss et al., 2019).

This name was originally spelled waterhousii, but most subsequent authors have spelled it waterhousei . The latter spelling would appear to have been an incorrect subsequent spelling (in the special sense of the Code) when it was first adopted by Thomas (1888a), but waterhousei is the spelling in prevailing usage today and should be maintained ( ICZN, 1999: Article 33.3.1).