Marmosa (Exulomarmosa), Voss & Gutiérrez & Solari & Rossi & Jansa, 2014

Voss, Robert S., Gutiérrez, Eliécer E., Solari, Sergio, Rossi, Rogério V. & Jansa, Sharon A., 2014, Phylogenetic Relationships of Mouse Opossums (Didelphidae, Marmosa) with a Revised Subgeneric Classification and Notes on Sympatric Diversity, American Museum Novitates 2014 (3817), pp. 1-1 : 1-

Exulomarmosa , new subgenus

TYPE SPECIES: Marmosa robinsoni Bangs, 1898 .

CONTENTS: isthmica Goldman, 1912 (including mimetra Thomas, 1921); mexicana Merriam, 1897 (including mayensis Osgood, 1913; ruatanica Goldman, 1911; and savannarum Goldman, 1917); robinsoni Bangs, 1898 (including casta Thomas, 1911; chapmani J.A. Allen, 1900; fulviventer Bangs, 1901; grenadae Thomas, 1911; luridavolta Goodwin, 1961; mitis Bangs, 1898; nesaea Thomas, 1911; and pallidiventris Osgood, 1912); simonsi Thomas, 1899 ; xerophila Handley and Gordon, 1979 ; and zeledoni Goldman, 1917 .

DIAGNOSIS: Gular gland consistently present and well developed in adult males; manual claws small (not extending beyond fleshy apical pads of fingers); medial and lateral carpal tubercles present in large adult males 6; dorsal tail scales rhomboidal or oblong, usually in both spiral and annular series on most specimens, but one or the other pattern sometimes predominating; ventral prehensile surface of tail not densely fringed with long hairs. Postorbital processes usually absent, indistinct, or very small in some species (e.g., Marmosa zeledoni ) but consistently large and well developed in adults of other species (e.g., M. simonsi ); palatine fenestrae consistently absent in some species (e.g., M. isthmica ) but consistently present in others (e.g., M. xerophila ); fenestra cochleae usually exposed (but partially concealed in a few examined specimens of M. robinsoni , M. simonsi , and M. xerophila ); M2 preparacrista attaches to or terminates near stylar cusp B.

COMPARISONS: Comparisons of Exulomarmosa with Eomarmosa have already been provided (see above). Species of Exulomarmosa differ consistently from members of the subgenus Marmosa in sexually dimorphic features of the carpal (wrist) region: whereas large adult male specimens of Exulomarmosa have well-developed lateral and medial carpal tubercles, neither sex has large carpal tubercles in the subgenus Marmosa . Additionally, gular glands are consistently well developed (especially in adult males) in Exulomarmosa , but gular glands are absent in most species of Marmosa (appearing polymorphically only in M. waterhousei ; Rossi, 2005). Exulomarmosa also differs from Micoureus in possessing gular glands, and these subgenera further differ in manual claw morphology (small in Exulomarmosa , large in Micoureus ). In Exulomarmosa the caudal prehensile surface lacks the dense lateral fringes of long hairs that occur in both species of Stegomarmosa .

REMARKS: Morphological diagnoses of the species in this subgenus were provided by Rossi et al. (2010), who also discussed relevant synonymies. At least two species ( Marmosa mexicana and M. robinsoni ) contain highly divergent mtDNA haplotype groups that might represent cryptic taxa ( Gutiérrez et al., 2010; Gutiérrez et al., in press).

6 Exemplar adult male specimens in which these tubercles are well developed include AMNH 12454 ( Marmosa mexicana ), AMNH 37890 ( M. isthmica ), AMNH 66852 ( M. simonsi ), AMNH 69939 ( M. robinsoni ), USNM 443920 ( M. xerophila ), and AMNH 147759 ( M. zeledoni ). The same specimens also exhibit the well-developed gular gland that characterizes this subgenus.