Thylamys (Xerodelphys), Giarla & Voss & Jansa, 2010

Giarla, T. C., Voss, R. S. & Jansa, S. A., 2010, Species Limits And Phylogenetic Relationships In The Didelphid Marsupial Genus Thylamys Based On Mitochondrial Dna Sequences And Morphology, Bulletin of the American Museum of Natural History 2010 (346), pp. 1-67 : 34-36

Xerodelphys , new subgenus

TABLE 14

Nominal Species-group Taxa Referred to Thylamys , Type Specimens, and Type Localities a

DIAGNOSIS: Members of the subgenus Xerodelphys can be distinguished from other congeners (herein referred to the nominotypical subgenus, see below) by their reduction or loss of plantar dermatoglyphs, lack of a concave central palmar surface, tails that are shorter than the combined length of head and body, and absence of distinct modifications for caudal prehension (table 15).

REMARKS: Although the monophyly of Xerodelphys is only weakly supported by phylogenetic analyses of our concatenated- gene dataset ( fig. 11), the absence of a concave central palmar surface (resulting from fusion of plantar pads on the manus) and the reduction or loss of plantar dermatoglyphs are unique in the family Didelphidae and provide supporting evidence that these two species form a clade. Sequence data from nuclear loci will presumably allow future tests of this hypothesis.

The morphological distinctness of the taxa we refer to Xerodelphys was previously recognized by Solari (2003), who, however, regarded karimii as a synonym of velutinus . Carmignotto and Monfort (2006) were the first to clearly identify the diagnostic traits that distinguish T. karimii and T. velutinus from each other and from congeneric species that we refer to the nominotypical subgenus, but they prudently refrained from naming a new genus-group taxon in the absence of a supporting phylogenetic analysis. We commend their restraint and credit them with the morphological observations on which our subgeneric diagnosis is based.