Thylamys citellus (Thomas, 1912)

Russell A. Mittermeier & Don E. Wilson, 2015, Didelphidae, Handbook of the Mammals of the World – Volume 5 Monotremes and Marsupials, Barcelona: Lynx Edicions, pp. 129-186 : 177

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Thylamys citellus


82. View Plate 9: Didelphidae

Mesopotamian Fat-tailed Opossum

Thylamys citellus

French: Opossum d'Entre Rios / German: Pampas-Fettschwanzbeutelratte / Spanish: Marmosa coligruesa de Mesopotamia

Taxonomy. Marmosa citella Thomas, 1912 ,

“ Goya , Corrientes, Argentina.”

This species is monotypic.

Distribution. NE Argentina (Entre Rios and Corrientes S of Ibera Wetlands). View Figure

Descriptive notes. Head-body 9.9-11.5 cm, tail 10.2-12.5 cm; weight 55-66 g. Dorsal fur of the Mesopotamian Fat-tailed Opossum is brownish with an overall cinnamon tint and the typical tricolored pattern of species of Thylamys , markedly paler on body sides. Mid-dorsal fur has four-color, banded cover hairs: hairs are gray at bases, followed by a narrow, dark brown band, then a creamy brown one. Tips of hairs are dark; guard hairs are brownish with dark bases. Head is colored as dorsum, but facial fur is paler, with distinct dark mid-rostral stripe and moderately developed dark brown eye-rings that extend toward but do not reach nose. Tail length is ¢.105% of head-body length, and tail is bicolored proximally (dark brown dorsally and whitish ventrally), entirely white on distal one-fifth to one-sixth of its length. When tail is incrassated (enlarged with stored fat), it reaches 6-7 mm in diameter. Ventral fur is creamy white from cheeks to anus, and fur on throat sometimes has yellowish tint. Fur is soft and fine, long and dense in mid-dorsum, with 8-9 mm long cover hairs and longer (10-11 mm) guard hairs. Hairs in ventral region are shorter (7-8 mm long). Forefeet and hindfeet are large and whitish. Ears are large and rounded, dark brown at their tips and yellowish at their bases, and they appear naked except for conspicuous tufts of whitish hairs at their posterior bases. Females lack a pouch, and 13 mammae are present, six on each side and a medial mamma. Karyotype of the Mesopotamian Fat-tailed Opossum is unknown.

Habitat. Seasonally flooded forests and grasslands in a landscape composed of grassy savannas, open grasslands, and wetlands with patches of palm savannas, subtropical gallery forests, and xerophytic woodlands. The Mesopotamian Fat-tailed Opossum occurs in Southern Cone Mesopotamian Savanna and Mesopotamian sector of the Humid Pampas ecoregions.

Food and Feeding. There is no information available for this species.

Breeding. There is no information available for this species.

Activity patterns. There is no information available for this species.

Movements, Home range and Social organization. There is no information available for this species.

Status and Conservation. Classified as Least Concern on The IUCN Red List. The Mesopotamian Fat-tailed Opossum has wide distribution and presumably a large overall population. It occurs in at least one protected area (El Palmar National Park, Entre Rios Province) and is tolerant of some degree of habitat modification. Its area of occurrence, however, is directly affected by habitat degradation or conversion for agriculture or pastures for cattle, so it conservation status needs to be carefully monitored.

Bibliography. Giarla et al. (2010), Palma et al. (2014), Teta, D'Elia et al. (2009).














Thylamys citellus

Russell A. Mittermeier & Don E. Wilson 2015

Marmosa citella

Thomas 1912