Marmosops magdalenae, Díaz-Nieto & Voss, 2016

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 : 58-59

Marmosops magdalenae , new species

Figures 5C , 6B , 25–27

HOLOTYPE: ICN 19924 (original number MRP82 ), consisting of the skin and skull of an adult female collected by Miguel E. Rodríguez- Posada on 18 July 2002 at Bosque de Roble Cerca de Torre , Reserva Biológica Cachalú (fig. 28: locality 33), vereda Rionegro, municipio Encino, Santander, Colombia.

DISTRIBUTION AND SYMPATRY: Examined specimens of Marmosops magdalenae are from east of the Río Magdalena in northern Colombia, where it has been collected between 104 m and 1940 m above sea level (fig. 28). Capture habitats include lowland rain forest along the right bank of the Río Magdalena (e.g., at Corregimiento Campo Capote [fig. 28: locality 34]) and lower montane moist forest on the western slope of the Cordillera Oriental (e.g., at Reserva Biológica Cachalú [fig. 28: locality 33]; Otálora- Ardila, 2003; Ávila et al., 2010). This species is not known to occur sympatrically with any other congener, but at the upper limit of its elevational range it might cooccur with M. caucae , a member of the nominotypical subgenus that is widespread in Andean cloud forests ( Díaz-Nieto et al., 2016a).

DESCRIPTION: Body pelage fuscous to reddish brown (near Dresden Brown) middorsally, indistinctly paler laterally, and about 9 mm long at midback (based on FMNH 70926); ventral pelage self-white from chin to groin (including the inside surface of the forelimbs and sometimes also the hind limbs), but midventral band of self-white fur narrowed by lateral zones of gray-based abdominal hairs (sometimes with brownish tips) on abdomen. Manus covered dorsally with uniformly pale fur, without pigmental contrast between the metacarpal and digital pelage; lateral carpal tuber- cles bladelike in all examined adult males. Mammary formula unknown. 17 Tail longer than combined length of head and body (mean LT/ HBL × 100 = 125%–130%), indistinctly bicolored, and somewhat paler distally than proximally (but not distinctly particolored).

Nasals not very long (usually not extending posteriorly behind lacrimals) 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 jugal. Palatine fenestrae consistently present and large. Dorsolateral margin of ethmoid foramen usually formed by the frontal.

Upper canines short, with posterior accessory cusps in both sexes (anterior accessory cusps consistently absent in all examined material). 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 absent or indistinct. Entoconid of m1 shorter than adjacent m2 paraconid; unworn m4 talonid usually with only two distinct cusps.

COMPARISONS: Comparisons between Marmosops magdalenae and other species of the Bishopi Group have already been provided in the preceding accounts.

ETYMOLOGY: For the Río Magdalena, economically and culturally the most important river of Colombia, and a well-known dispersal barrier for the terrestrial vertebrate fauna of northwestern South America ( Chapman, 1917; Gutiérrez-Pinto et al., 2012).

REMARKS: The material that we refer to Marmosops magdalenae was previously identified in

17 The skin tag of ICN 19924 mentions the presence of “6 mamas,” but no mammary formula was provided. We inspected the skin of this specimen and found 6 teats in the arrangement 3–1–2. Because no species of Marmosops is known to have unpaired lateral mammae it seems probable that additional mammae are normally present in this species.

the literature as Marmosa parvidens by Pine (1981), as Marmosops parvidens by Díaz-N. et al. (2011), and as Marmosops “East Magdalena ” by Díaz-Nieto et al. (2016a).

SPECIMENS EXAMINED (N = 3): Colombia — Boyacá, Muzo ( FMNH 70926 ) ; Huila, near San Adolfo ( FMNH 70927 , 70928 ) ; Santander, Encino ( ICN 19924), Puerto Parra ( ICN 18788) .

Figures

FIG. 5. Ventral views of the palates of Marmosops parvidens (A, AMNH 267359), M. juninensis (B, AMNH 230016), and M. magdalenae (C, ICN 19926) illustrating species differences in the presence, absence, and morphology of palatal fenestrae and foramina. Abbreviations: if, incisive foramen; max, maxillary bone; mp, maxillopalatine fenestra; p, palatine fenestrae; pal, palatine bone; plpf, posterolateral palatine foramen; pre, premaxillary bone.

FIG.6. Lateral view of anterior left upper dentition (I1– P1) of Marmosops pinheiroi (A, AMNH 267349), M. magdalenae (B, ICN 18788), and M. carri (C, KU 120254) illustrating species differences in the presence or absence of accessory upper canine (C1) cusps. All illustrated specimens are males. Abbreviations: aac, anterior accessory cusp; pac, posterior accessory cusp.

FIG. 25. Dorsal views of skulls of Marmosops ojastii (left, USNM 371299), M. chucha (center, CTUA 434), and M. magdalenae (right, ICN 19924). All views about ×3.

FIG. 26. Ventral views of skulls of Marmosops ojastii (left, USNM 371299), M. chucha (center, CTUA 434), and M. magdalenae (right, ICN 19924). All views about ×3.

FIG. 27. Lateral views of skulls of Marmosops ojastii (above, USNM 371299), M. chucha (center, CTUA 434), and M. magdalenae (below, ICN 19924). All views about ×3.