Marmosops handleyi ( Pine, 1981 )

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 : 37-40

Marmosops handleyi ( Pine, 1981)

Figures 2 , 18 , 19

Marmosa handleyi Pine, 1981: 67 (original description).

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

TYPE MATERIAL: The holotype (by original designation) consists of the skin, skull, and postcranial skeleton of an adult female ( FMNH 69838 ; original number PH 4371) collected by Philip Hershkovitz at a site 9 km south of Valdivia (fig. 20: locality 24) in the Colombian department of Antioquia at an elevation of 1400 m on 16 June 1950. In addition, Pine’s (1981) original material included an adult male paratype ( FMNH 70926 ) .

DISTRIBUTION, HABITATS, AND SYMPATRY: Examined specimens of Marmosops handleyi are all from the northern terminus of the Cordillera Central (central Andes) of Colombia, where they have been collected in humid premontane and montane rain forest at elevations ranging from 1400 to 1950 m (fig. 20). This species has been collected sympatrically with M. chucha (a new species of the Bishopi Group; see below) and with M. caucae (a member of the nominotypical subgenus; Díaz-N. et al., 2011).

DESCRIPTION: Body pelage dark brown to chestnut brown middorsally, indistinctly paler laterally, about 9–10 mm long at midback, and somewhat woolly in texture; ventral pelage superficially whitish, but hairs of throat, chest, and abdomen uniformly gray based (only the apex of the chin, the oral margins, the scrotum, and mammary region consistently have selfwhite fur). 9 Metacarpals covered dorsally with dark hairs (contrasting in color with the pale manual digits); lateral carpal tubercles bladelike. Mammary formula 3–1–3 = 7 in all examined females with conspicuous teats. Tail longer than combined length of head and body (mean LT/ HBL × 100 = 125%), dorsal caudal surface dark gray but somewhat paler distally; ventral caudal surface distinctly paler.

Nasal bones long (extending well behind the lacrimals) and much wider posteriorly than anteriorly (laterally expanded at the maxillary-frontal suture). Upper lacrimal foramen not visible in lateral view, but lower foramen laterally exposed; zygomatic process of squamosal broadly overlapped dorsally by the jugal. Palatine fenestrae present (usually as a pair of large rounded perforations). Dorsolateral margin of ethmoid foramen with equal contribution of frontal and orbitosphenoid.

9 Pine (1981: 68) described the dorsal pelage as “fuscous,” a grayer shade than we observed in fresh skins. Unfortunately, none were compared by us with color swatches in Ridgway (1912). One specimen (CTUA 415, a subadult male) has a 5 × 15 mm midventral streak of self-white abdominal hairs.

Upper canine (C1) short in both sexes but sexually dimorphic in shape: male C1 with posterior accessory cusp only, female C1 with both anterior and posterior accessory cusps. Upper third molar (M3) anterolabial cingulum discontinuous with preprotocrista (anterior cingulum incomplete). Lower canine (c1) premolariform (procumbent, with posterior accessory cusp) and small, subequal in height to p1; c1 anterolingual accessory cusp present. Entoconid of m1 subequal in height to adjacent m2 paraconid; unworn m4 talonid with three distinct cusps.

COMPARISONS: Comparisons of Marmosops handleyi with M. carri and M. fuscatus have already been described (see above).

Although Marmosops handleyi averages slightly larger than M. invictus in most same-sex comparisons of external dimensions (tables 5, 6), sample sizes for both species are small, and it seems unlikely that any external measurement will prove to be diagnostic as more material becomes available. A more consistent external difference between these species is pelage color (distinctly brownish in handleyi versus dark grayish brown to blackish gray in invictus ) and fur length (9–10 mm middorsally in handleyi versus 6–7 mm in invictus ). The two species broadly overlap in craniodental measurements, none of which, therefore, is useful for identification. Instead, M. handleyi is more readily distinguished from M. invictus by the consistent presence of palatine fenestrae (consistently absent in M. invictus ), by the presence of both anterior and posterior accessory C1 cusps in females (females usually have only a posterior accessory C1 cusp in M. invictus ), by lacking a complete M3 anterior cingulum (M3 has a narrowly complete anterior cingulum in M. invictus ), and by having an m1 entoconid that is subequal in height to the adjacent m2 paraconid (the m1 entoconid is shorter than the m2 paraconid in invictus ).

REMARKS: Marmosops handleyi had not been collected for 60 years before it was rediscovered and redescribed by Díaz-N. et al. (2011), whose report should be consulted for additional mor- phological, geographical, and ecological information. Using the dichotomous key in Gardner and Creighton (2008), this species would be misdidentified as M. juninensis .

SPECIMENS EXAMINED (N = 10): Colombia— Antioquia, Finca Costa Rica (CTUA 410–412, 433); Finca El Bosque (CTUA 413, 414), Finca Villa Nueva (CTUA 415, 416), 9 km S Valdivia (FMNH 69823, 69838).

Figures

FIG. 2. Marmosops handleyi (above; photographed by J. Díaz-Nieto at Finca Costa Rica, Antioquia, Colombia) and M. parvidens (below; photographed by T. Semedo near Urucará, Amazonas, Brazil). In addition to obvious differences in body pelage color, these species differ in forefoot markings: whereas M. handleyi has dark metacarpal fur that contrasts with the pale fur of the manual digits, M. parvidens has all-pale forefeet.

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.