Gracilinanus emiliae ( Thomas, 1909 )

Voss, Robert S., Fleck, David W. & Jansa, Sharon A., 2019, Mammalian Diversity And Matses Ethnomammalogy In Amazonian Peru Part 3: Marsupials (Didelphimorphia), Bulletin of the American Museum of Natural History 2019 (432), pp. 1-89 : 57-58

Gracilinanus emiliae ( Thomas, 1909)

Figures 9C , 10C

VOUCHER MATERIAL (TOTAL = 1): Nuevo San Juan (MUSM 15292).

OTHER INTERFLUVIAL RECORDS: None.

IDENTIFICATION: Our single voucher conforms in all respects to the morphological diagnosis of Gracilinanus emiliae provided by Voss et al. (2009b), who also tabulated external and craniodental measurements of MUSM

15292 and compared them with homologous values from other specimens, including Thomas’s (1909) subadult holotype. Within the Yavarí-Ucayali interfluve G. emiliae might be confused with two superficially similar sympatric species, Hyladelphys kalinowskii and Marmosa lepida , but numerous external and craniodental differences are sufficient for unambiguous identifications of specimens in hand (table 4).

Gracilinanus emilae is the only species of Gracilinanus expected to occur in the Yavarí-Ucayali interfluve, although G. peruanus —formerly synonymized with G. agilis (see Semedo et al., 2015)—is known from scattered localities in the lowlands and foothills of central and southern Peru. Based on material we examined, G. peruanus occurs in the departments of Cusco (e.g., at La Convención, Camisea, San Martín: MUSM 14086), Huánuco (Tingo Maria: BMNH 27.11.1.268, 27.11.1.269), Madre de Dios (Pakitza: MUSM 8922), Pasco (near Villa Rica: AMNH 67242), and Ucayali (Balta: LSUMZ 16378). 10 The only other Peruvian congener, G. aceramarcae , appears to be a strictly montane taxon. Semedo et al. (2015: table 10) provided diagnostic comparisons among the three known Peruvian species of Gracilinanus .

Recently reported specimens of Gracilinanus emiliae from scattered localities in Brazil ( Silva et al., 2013; Brandão et al., 2014; Rocha et al., 2015) confirm that this species is very widely distributed in Amazonia. Despite substantial (ca. 5%) divergence at the cytochrome b locus between our Peruvian voucher and the eastern Amazonian material analyzed by Rocha et al. (2015), 10 The specimen that Huamani et al. (2009) reported as Gracilinanus agilis from the Zona Reservada Pucacuro in northern Loreto (MUSM 24430) is a juvenile specimen of G. emiliae . Another specimen that Huamani et al. (2009) identified as G. agilis (MUSM 14085) is an unidentifiable Marmosops with molar teeth worn almost to the roots. The specimens from Bellavista (in Cajamarca department [ Stephens and Traylor, 1983]) that Tate (1933: 199) tentatively identified as “ Marmosa agilis peruana ” (MCZ 17057–17059) consist only of skins; although these are unambiguously identifiable as Gracilinanus , and are clearly not G. emiliae (the ventral fur is extensively gray-based), they are not identifiable to species without cranial material.

this appears to be a phenotypically homogeneous taxon, without any obvious morphological differences among the specimens we examined.

ETHNOBIOLOGY: The Matses do not distinguish this species from other pouchless, longtailed, black-masked species of small opossums (all known as chekampi; see the account for Marmosa , above) and therefore have no particular beliefs about it.

MATSES NATURAL HISTORY: The Matses have no definite knowledge of this species.

REMARKS: Our single specimen was shot at night by a Matses hunter in hilltop primary forest as it perched low in the crown of an understory tree.

OTHER SPECIMENS EXAMINED (TOTAL = 11): Brazil — Pará, Belém (BMNH 9.3.9.10 [holotype]), Capím (AMNH 203363). Colombia — Meta, Los Micos (FMNH 87924). French Guiana —Paracou (AMNH 267006). Guyana — Upper Takutu-Upper Essequibo, 20 mi E Comiwariwau Head (ROM 33103), 12 km E Dadanawa (ROM 35465, 35466), 40 mi E Dadanawa (ROM 55519). Peru — Loreto, Zona Reservada Pucacuro (MUSM 24430). Surinam — Marowijne, Langamankondre (RMNH 18231). Venezuela — Monagas, 47 km SE Maturín (USNM 385066).

Figures

FIG. 9. Dorsal and ventral cranial views of three small opossums. A, Hyladelphys kalinowskii (AMNH 267338, an adult male from French Guiana); B, Marmosa lepida (AMNH 273186, an adult male from the Yavarí- Ucayali interfluve); C, Gracilinanus emiliae (MUSM 15292, an adult female from the Yavarí-Ucayali interfluve). Abbreviations: amp, anteromedial process of the alisphenoid bulla (enclosing a secondary foramen ovale); pal, palatine fenestra; pop, postorbital process (of frontal); rp, rostral process (of premaxilla).

FIG. 10. Lateral cranial views of three small opossums (same specimens as in fig. 9). A, Hyladelphys kalinowskii; B, Marmosa lepida; C, Gracilinanus emiliae. Abbreviations: P2, second upper premolar; P3, third upper premolar; pac, posterior accessory cusp (of upper canine); rp, rostral process (of premaxilla).