Marmosops pinheiroi ( 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 : 26-27

Marmosops pinheiroi ( Pine, 1981)

Figures 1 , 3A , 6A , 9A , 11–13 , 14B

Marmosa parvidens pinheiroi Pine, 1981: 61 (original description).

Marmosa parvidens woodalli Pine, 1981: 62 (original description). Type locality “Nova Area Experimental, Utinga (the wooded area surrounding the Belém waterworks), Belém (1°27′ S, 48°29′ W), Pará, Brazil.”

Marmosops parvidens: Gardner, 1993: 20 , part (name combination; pinheiroi and woodalli listed as synonyms).

Marmosops pinheiroi: Voss et al., 2001: 49 (first use of current binomial).

TYPE MATERIAL: The holotype (by original designation) consists of the skin and skull of an adult male ( USNM 461459, original numbers T-391 and L5049), said to have been collected by personnel of the Instituto Evandro Chagas on 8 May 1969 at Rio Amapari, Serra do Navio (fig. 10: locality 7), Amapá, Brazil. In addition, Pine (1981) examined 15 other specimens (paratypes), but one of these ( USNM 385045) is also a paratype of M. pakaraimae , and two others ( AMNH 130521, USNM 385046) might also be referable to the latter species ( Voss et al., 2013).

DISTRIBUTION, HABITATS, AND SYMPATRY: Based on the material we examined, Marmosops pinheiroi occurs in eastern Venezuela, Guyana, Surinam, French Guiana, and Brazil (Amapá and eastern Pará). We have not examined the specimens that Nascimento et al. (2015) recently identified as M. pinheiroi from the Brazilian state of Maranhão, which would be a significant ecogeographic range extension if their material were correctly identified (see Remarks, below). Throughout its known range, this species probably cooccurs with M. parvidens , but the two have been collected sympatrically only in French Guiana ( Voss et al., 2001; Catzeflis et al., 2014). Specimens of M. pinheiroi associated with definite elevational data were collected from near sea level to about 500 m. The predominant vegetation throughout the geographic range of this species—as documented by examined specimens—is lowland rain forest (e.g., at Paracou, French Guiana; Voss et al., 2001).

DESCRIPTION: Body pelage brownish gray (near Olive Brown or Fuscous) middorsally, but indistinctly paler laterally, and about 6–8 mm long at midback; ventral pelage superficially whitish but extensively gray based in most specimens (only the chin, groin, and a narrow midventral streak of abdominal fur are usually self-white); inner surfaces of fore- and hind limbs covered with gray-based fur, apparently never self-white. Manus covered dorsally with uniformly pale hairs (the metacarpals not contrasting sharply in color with the digits); lateral carpal tubercles spoon shaped in all examined adult males. Mammae 3–1–3 = 7 or 4–1–4 = 9. Tail much longer than combined length of head and body (mean LT/HBL × 100 = 150%); dorsal caudal surface uniformly dark from base to tip, but ventral surface indistinctly paler (especially near the base of the tail).

Nasal bones long (extending well behind the lacrimals) and much wider posteriorly than anteriorly (laterally expanded at the maxillary-frontal suture). Lacrimal foramina usually exposed in lateral view; zygomatic process of squamosal bone broadly overlapped dorsally by the jugal. Palatine fenestrae absent. Dorsolateral margin of ethmoid foramen formed by the orbitosphenoid in some specimens (e.g., ROM 108920, AMNH 267340, 267346), by the frontal in others (e.g., AMNH 267341, 267342), occasionally with bilateral variation (e.g., AMNH 267345).

Upper canine (C1) short, apparently always with anterior and posterior accessory cusps in both sexes. Upper third molar (M3) anterolabial cingulum discontinuous with preprotocrista (anterior cingulum incomplete). Lower canine (c1) premolariform (procumbent, with posterior accessory cusp) and subequal in height to p1; c1 anterolingual accessory cusp absent. Entoconid of m1 shorter than adjacent m2 paraconid in some specimens (e.g., AMNH 266423, 267342, 267345), but these cusps subequal in others (e.g., AMNH 267349, 267357); unworn m4 talonid often with only two distinct cusps.

COMPARISONS: Diagnostic comparisons of Marmosops pinheiroi with M. pakaraimae and M. parvidens are provided in earlier species accounts (see above).

REMARKS: In our previous analyses of molecular sequence data ( Voss et al., 2013; Díaz-Nieto et al., 2016a), we recovered two cytochrome- b haplogroups among the material here referred to Marmosops pinheiroi , the first consisting of six sequences from the Guianas and the second including two sequences from southeastern Pará (south of the Amazon and east of the Rio Xingu). On the assumption that these haplogroups are physically separated by the lower Amazon, then the epithet pinheiroi could be associated with the former group and woodalli with the latter. Although this phylogeographic structure is robustly supported, these haplogroups differ on average by only 3.9% in uncorrected pairwise sequence comparisons, and we are unable to morphologically distinguish their corresponding voucher material. Therefore, we continue to treat woodalli as a junior (subjective) synonym.

The specimens that Nascimento et al. (2015) identified as Marmosops pinheiroi extend the potential range of this species by almost 700 km, into the Brazilian state of Maranhão. These specimens are also remarkable for having been collected in savanna, whereas all others known to us have been taken in lowland rain forest. Unfortunately, the identification of this interesting material is apparently based only on sequence analysis and external measurements. Supporting evidence from craniodental morphology would be very welcome.

SPECIMENS EXAMINED (N = 33): Brazil — Amapá, Serra do Navio (USNM 461459, 461460, 461462–461465); Pará, 52 km SSW Altamira (USNM 549294), Belém (USNM 545543), Utinga (USNM 393529–393532, 393534). French Guiana —Paracou (AMNH 266423, 267340, 267341, 267342, 267345, 267346, 267349, 267352, 267357; MNHN 1995-931, 1995-932). Guyana — Potaro-Siparuni, Forest Canopy Walkway (ROM 119852), 10 km NW Kurupukari (ROM 108920), Kabukalli Landing (ROM 111558, 111663). Surinam — Bokopondo, Finisanti (FMNH 95320); Nickerie, Sipaliwini Airstrip (CM 63506); Sipaliwini, Bakhuis Transect (ROM 116974). Venezuela— Bolívar, Auyántepui (AMNH 130568, 130570).

Figures

FIG. 1. Dorsal and ventral cranial views and occlusal view of the maxillary dentition of Marmosops pinheiroi, showing the anatomical limits of 11 craniodental measurements defined in the text.

FIG. 3. Plantar views of left forefoot (manus) and wrist of Marmosops pinheiroi (A, AMNH 267346) and M. bishopi (B, MUSM 23801) illustrating different morphologies of the lateral carpal tubercle (lct), which is spoon shaped in adult males of M. pinheiroi and bladelike (laterally compressed) in adult males of M. bishopi.

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. 9. Lateral view of posterior braincase of Marmosops (Sciophanes) pinheiroi (A, AMNH 267345) and M. (M.) noctivagus (B, MUSM 13288) illustrating diagnostic subgeneric morphologies of the squamosal (green) and petrosal (yellow). Abbreviations: als, alisphenoid; exo, exoccipital; lspc, lateral surface of pars canalicularis (of petrosal); par, parietal; pet, petrosal; sps, sulcus for the prootic sinus (of petrosal); sq, squamosal; ssf, subsquamosal foramen; zps, zygomatic process of the squamosal.

FIG. 11. Dorsal views of skulls of the Parvidens Group of Sciophanes. Left to right: Marmosops pakaraimae (ROM 115129, holotype), M. parvidens (AMNH 267359), and M. pinheiroi (AMNH 267345). All views about ×3.

FIG.12. Ventral views of skulls of the Parvidens Group of Sciophanes. Left to right: Marmosops pakaraimae (ROM 115129, holotype), M. parvidens (AMNH 267359), and M. pinheiroi (AMNH 267345). All views about ×3.

FIG. 13. Lateral views of skulls and mandibles of the Parvidens Group of Sciophanes. Top to bottom: Marmosops pakaraimae (ROM 115129, holotype), M. parvidens (AMNH 267359 [skull], 267353 [mandible]), and M. pinheiroi (AMNH 267345). All views about ×3.

FIG.14. Lateral views of the anterior orbital region of Marmosops parvidens (A, AMNH 267359) and M. pinheiroi (B, AMNH 267345) illustrating species differences in the lacrimal foramina (lf), which are usually concealed inside the orbit in M. parvidens, but which are laterally exposed on the orbital margin of M. pinheiroi.