Marmosops impavidus (Tschudi, 1845)

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 : 184

97.

Tschudi’s Slender Opossum

Marmosops impavidus

French: Opossum pale / German: Tschudis Schlankbeutelratte / Spanish: Marmosa esbelta de Tschudi

Other common names: Andean Slender Mouse Opossum, Tschudi’s Slender Mouse Opossum

Taxonomy. Didelphys impavida Tschudi, 1845 ,

“der mittleren und tiefern Waldregion.” Interpreted by A. Cabrera in 1958 as “ Montana de Vitoc , cerca de Chanchamayo,” Junin, Peru.

This species is currently considered to be monotypic, but it is possible that some of the synonyms currently included in this taxon may represent distinct species. Monotypic.

Distribution. W slope of the Andes from N Colombia (La Guajira) to S Ecuador (Loja) and E slope from SW Venezuela (Tachira) to S Peru (Cusco), also in W Brazil (Amazonas, Acre) and N Bolivia (Pando).

Descriptive notes. Head-body 9.7-15.2 cm, tail 13.2-20.5 cm; weight 25-51 g. Dorsal fur of Tschudi’s Slender Opossum is dull grayish-brown (predominantly in younger specimens) to reddish-brown (predominantly in older adults). Large black eye-rings contrast with pale brown fur on muzzle, and cheeks are pale orange to buff. Tail length is ¢.135% of head-body length, and tail has short fur on proximal 1.5-2 cm. Naked part of tail can be uniformly dark brown dorsally and ventrally, or indistinctly paler ventrally than dorsally, or paler distally than proximally. Ventralfur is gray-based, paler than dorsal fur, and washed with orange, cream, whitish, tawny, or pinkish-brown. Partial or complete stripe of white or pale fur occurs along midline from chin to anus. Some individuals have entirely gray-based ventral fur with buff tips. Throat gland is absent. Fur measures 7-9 mm on rump. Hindfeet are dusky with white toes, forefeet are white, and males have lateral carpal tubercles. Females lack a pouch and have seven to nine mammae, three to four on each side and a medial mamma. Tschudi’s Slender Opossum has a 2n = 14, FN = 24 karyotype, with all biarmed autosomes, and with a small biarmed X-chromosome and a very small acrocentric Y-chromosome. Skull size and shape are sexually dimorphic.

Habitat. Cloud forests, montane wet forests, and lowland rainforests at elevations of 65-2200 m. Tschudi’s Slender Opossum have been captured in undisturbed and second-growth terra firma forest and cultivated fields.

Food and Feeding. There is no specific information available for this species, but Tschudi’s Slender Opossum appears to feed on fruits and insects.

Breeding. In the Brazilian Amazon, all adult female Tschudi’s Slender Opossums collected in the wet season showed signs of recent lactation but had no pouch young; a female captured during the dry season was ajuvenile. It apparently breeds at least during the wet season. In Peru,a lactating female was collected in September.

Activity patterns. There is no specific information available for this species, but Tschudi’s Slender Opossum is probably nocturnal.

Movements, Home range and Social organization. Tschudi’s Slender Opossums have been reported to be arboreal, but they are probably scansorial because individuals have been captured on the ground and in the understory, at heights of 1-5-2 m above ground,in trees, vines, and shrubs.

Status and Conservation. Classified as Least Concern on The IUCN Red List. Tschudi’s Slender Opossum has a wide distribution and presumably a large overall population. It occurs in several protected areas and can apparently tolerate some degree of habitat modification.

Bibliography. Astua (2010), Cabrera (1958), Diaz, J.F. et al. (2011), Diaz, M.M. (2014), Eisenberg (1989), Emmons & Feer (1997), Gardner (2005), Gardner & Creighton (2007a), Handley (1976), Hershkovitz (1992a), Patton & Costa (2003), Patton et al. (2000), Tate (1933), Voss, Tarifa & Yensen (2004).

Figures

76. Patagonian Opossum (Lestodelphys halli), 77. Karimi’s Fat-tailed Opossum (Thylamys karimii), 78. Dwarf Fat-tailed Opossum (Thylamys velutinus), 79. Elegant Fat-tailed Opossum (Thylamys elegans), 80. Pallid Fat-tailed Opossum (Thylamys pallidior), 81. Tate's Fat-tailed Opossum (Thylamys tatei), 82. Mesopotamian Fat-tailed Opossum (Thylamys citellus), 83. Dry Chaco Fat-tailed Opossum (Thylamys pulchellus), 84. Chacoan Fat-tailed Opossum (Thylamys pusillus), 85. Paraguayan Fat-tailed Opossum (Thylamys macrurus), 86. Argentine Fat-tailed Opossum (Thylamys sponsorius), 87. Buff-bellied Fat-tailed Opossum (Thylamys venustus), 88. Bishop's Slender Opossum (Marmosops bishop), 89. Junin Slender Opossum (Marmosops juninensis), 90. Delicate Slender Opossum (Marmosops parvidens), 91. Pantepui Slender Opossum (Marmosops pakaraimae), 92. Pinheiro’s Slender Opossum (Marmosops pinheiroi), 93. Handley’s Slender Opossum (Marmosops handleyi), 94. Gray Slender Opossum (Marmosops incanus), 95. Brazilian Slender Opossum (Marmosops paulensis), 96. Neblina Slender Opossum (Marmosops neblina), 97. Tschudi’s Slender Opossum (Marmosops impavidus), 98. Spectacled Slender Opossum (Marmosops ocellatus), 99. Creighton’s Slender Opossum (Marmosops creightoni), 100. White-bellied Slender Opossum (Marmosops noctivagus), 101. Narrow-headed Slender Opossum (Marmosops cracens), 102. Dusky Slender Opossum (Marmosops fuscatus), 103. Panama Slender Opossum (Marmosops invictus)

Distribution. W slope of the Andes from N Colombia (La Guajira) to S Ecuador (Loja) and E slope from SW Venezuela (Tachira) to S Peru (Cusco), also in W Brazil (Amazonas, Acre) and N Bolivia (Pando).