Marmosops invictus ( Goldman, 1912 )

Díaz-Nieto, Juan F. & Voss, Robert S., 2016, A Revision Of The Didelphid Marsupial Genus Marmosops, Part 1. Species Of The Subgenus Sciophanes, Bulletin of the American Museum of Natural History 2016 (402), pp. 1-72 : 40-42

Marmosops invictus ( Goldman, 1912)

Figures 4A , 18 , 19

Marmosa invicta Goldman, 1912: 3 (original description).

Didelphis (Marmosops) invicta: Matschie, 1916: 270 (name combination).

Marmosops invictus: Gardner and Creighton 1989: 4 (first use of current binomial).

TYPE MATERIAL: The holotype (by original designation) consists of the skin and skull of an adult male ( USNM 178708 ; original number 21517) collected by E.A. Goldman at Cana (fig. 20: locality 57), in Darién province, Panama, on 14 March 1912. In addition to the holotype, Goldman’s original material included an adult female paratype ( USNM 178709 ) .

DISTRIBUTION, HABITATS, AND SYMPATRY: Examined specimens of Marmosops invictus are all from eastern Panama with recorded elevations between 600 and 1500 m above sea level (fig. 20). Handley (1966), who may have examined more material than we have seen, gave the elevational range as ca. 450–1200 m and remarked that the species might occur throughout Panama in suitable habitat. Although the lower elevations at which this species occurs would support lowland rain forest in Amazonia, humid forests of distinctly montane character (e.g., those at the type locality; Goldman, 1920: figs. 1, 2) can be found well below 1000 m on the low mountains and foothills of Central America ( Myers, 1969). Premontane rain forest seems likely to be the usual habitat of this species, which is not known to occur sympatrically with any other species of the subgenus Sciophanes . However, M. caucae , a member of the nominotypical subgenus, occurs at elevations> 1400 m in the Darién highlands of eastern Panama (Loma Cana and Cerro Pirre) and probably coexists with M. invictus in some places.

DESCRIPTION: Dorsal body pelage uniformly dark grayish brown to blackish gray (near Bone Brown to Blackish Brown)—not appreciably paler laterally—and only about 6–7 mm long at midback; ventral fur silvery gray (the hairs with dark-gray bases and whitish tips) over throat, chest, and abdomen (only the chin, oral margins, and groin have self-white fur). Manus with dark fur over all or part of metacarpals (contrasting in color with whitish digits); lateral carpal tubercles bladelike. Mammae 3–1–3 = 7 in all examined females with visible teats. Tail longer than combined length of head and body (mean LT/HBL × 100 = 122%); dorsal caudal surface dark gray from base to tip; ventral caudal surface indistinctly paler in some specimens (e.g., USNM 306386), almost as dark as dorsal surface in others (e.g., USNM 309265).

Nasal bones long (extending well behind the lacrimals in most specimens) and much wider posteriorly than anteriorly (laterally expanded at the maxillary-frontal suture). Lacrimal foramina concealed from lateral view inside anterior orbital margin; zygomatic process of squamosal broadly overlapped dorsally by the jugal. Palatine fenestrae absent (but some specimens have minute palatine perforations on one or both sides). Dorsolateral margin of ethmoid foramen formed by the orbitosphenoid.

Upper canine (C1) short, usually with posterior accessory cusps in male and female specimens (two females—USNM 178709, 306386—have indistinct anterior accessory C1 cusps, and the holotype completely lacks accessory cusps). Upper third molar (M3) anterolabial cingulum narrowly continuous with preprotocrista (anterior cingulum complete). Lower canine (c1) premolariform (procumbent, with posterior accessory cusp) and small, subequal in height to p1; c1 anterolingual accessory cusp usually present. Entoconid of m1 subequal in height to adjacent m2 paraconid; unworn m4 talonid with three distinct cusps.

COMPARISONS: Comparisons of Marmosops invictus with other members of the Fuscatus Group have already been described (see above).

REMARKS: All of the material we examined for this revision was collected>50 years ago, and we are not aware of any recently collected specimens. However, Mangan and Adler (2000) reported trapping Marmosops invictus in the course of an ecological study in western Panama, well outside the specimen-documented range of this species. In the absence of voucher material, the identity of the animals they trapped and released remains to be determined.

In a recent discussion of cytochrome oxidase subunit I (COI) barcoding results, Lim (2012) reported the occurrence of Marmosops invictus in Panama and Ecuador, but the specimens he sequenced (ROM 116281, 118844, and F41897 ) 10 appear to have been misidentified. We examined the Panamanian specimen (ROM 116281), which consists of a skin and skull with all the diagnostic attributes of the nominotypical subgenus, not Sciophanes . In addition, its teeth are larger than those of any measured specimen of M. invictus (e.g., LM = 6.8 mm versus 6.0–6.5 mm), its ventral pelage includes a median streak of self-white fur, and it has well-developed palatine fenestrae. In these and other traits ROM 116281 resembles numerous specimens of a widespread species (or species complex) for which M. caucae is the oldest available name, and the cytochrome- b sequence that we ( Díaz-Nieto et al., 2016a) obtained from ROM 116281 also unequivocally associates this specimen with the M. caucae complex. The two Ecuadorean specimens (ROM 118844, F41897 ) cannot be found at present (Jacqueline Miller, personal commun.), but as their COI barcodes clustered with the barcode obtained from ROM 116281, it seems likely that they are also members of the M. caucae complex, which is abundantly represented among other sequenced Ecuadorean material ( Díaz-Nieto et al., 2016a).

SPECIMENS EXAMINED (N = 10): Panama— Darién, Cana ( USNM 178708 [holotype], 178709), Cerro Tacarcuna ( USNM 337959–337962 ), Tacarcuna Casita Camp ( USNM 309265 ), Tacarcuna Laguna Camp ( USNM 309266 , 309267 ) ; Panamá, Cerro Azul ( USNM 306386 ) .

Figures

FIG. 4. Dorsal views of the rostrum of Marmosops invictus (A, USNM 306386) and M. fuscatus (B, FMNH 22174), illustrating taxonomic differences in nasal width. Abbreviations: fro, frontal; max, maxillary; nas, nasal.

FIG. 18. Dorsal and ventral views of skulls of Marmosops handleyi (left, CTUA 411) and M. invictus (right, USNM 337962). All views about ×3.

FIG. 19. Lateral views of skulls and mandibles of Marmosops handleyi (above, CTUA 411) and M. invictus (below, USNM 337962). All views about ×3.