Marmosa murina (Linnaeus, 1758)

Astúa, D., 2015, Didelphidae, Handbook of the Mammals of the World – Volume 5 Monotremes and Marsupials, Barcelona: Lynx Edicions, pp. 129-186 : 140-141

17.

Linnaeus’s Mouse Opossum

Marmosa murina

French: Opossum murin / German: Maus-Zwergbeutelratte / Spanish: Marmosa de Linneo

Other common names: Murine Mouse Opossum, Murine Opossum

Taxonomy. Didelphis murina Linnaeus, 1758,

“Asia, America.” Restricted by O. Thomas in 1911 to “ Surinam.”

As treated here, this species includes M. tobagi as a synonym, but several taxa formerly included in M. murina have now been recognized as full species. Monotypic.

Distribution. Venezuela, the Guianas, Trinidad and Tobago Is, and C & E Brazil (including E Amazonia).

Descriptive notes. Head-body 9.1-24 cm, tail 13.9-28 cm; weight 19-100 g. Dorsal fur of Linnaeus’s Mouse Opossum varies from pale to dark grayish-brown, variably washed with pale or dark orangish-brown, and is slightly paler on body sides. Head has stripe of mid-rostral fur paler than crown of head and lacks mid-rostral stripe. It has black eyes and dark brown or blackish-brown prominent eye-rings that do not reach base ofears. Tail length is ¢.130% of head-body length, and tail has fur on proximal 10%. Naked part of tail is yellowish to dark brown, slightly paler on ventral side. Ventral fur has a wide stripe offur, varying in color from creamy to pale or dark yellowish to pinkish. Stripe is narrower in abdominal region and is bordered by creamy to orangish-gray-based fur from sides of chest to abdominal and inguinal regions and rarely on sides of neck and ventralsides of limbs. Furis short and velvety, and throat gland is present. Forefeet are orangish-brown or brown, and hindfeet are pale brown or whitish. Females lack a pouch and have eleven mammae, five on each side, and a medial mamma. Karyotype of Linnaeus’s Mouse Opossum is 2n = 14, FN = 24, with all biarmed autosomes, and with a metacentric or an acrocentric X-chromosome reported and an acrocentric Y-chromosome. An FN = 20 or FN = 22 have also been reported for specimens from north-eastern and central Brazil. Skull size and shape are sexually dimorphic.

Habitat. Variety of habitats from sea level to 1350 m in elevation, including several biomes such as dry and wet tropical forests, mangroves, tropical savannas and forests, and xerophytic forests. In Brazil, presence of Linnaeus’s Mouse Opossums in open habitats is restricted to gallery forests or forested enclaves. They seem to be tolerant of human presence and habitat perturbation. In French Guiana, they are found living inside traditional houses of indigenous Wayampi, and in north-eastern Brazil, they frequently are found in or near houses located near forest fragments.

Food and Feeding. Diet of Linnaeus’s Mouse Opossum in French Guiana is mostly insectivorous, including Coleoptera, Hymenoptera (mostly ants), Myriapoda, and Annelida. It also eats fruits and has been seen consuming pulp of Bellucia (Melastomataceae) , Cecropia (Urticaceae) , Ficus (Moraceae) , Henriettea (Melastomataceae) , and sometimes fallen fruits. It also includes flowers and nectar, and occasionally frogs, in its diet. It is possible that it discards larger seeds when consuming pulp, so estimates of fruit consumption based on presence or absence of seeds in feces may be underestimated. When on the ground, Linnaeus’s Mouse Opossums forage under dried leaves for arthropods. In south-eastern Brazil, arthropods were found in 100% offecal samples analyzed and seeds were found in 50% of them.

Breeding. Average littersize of Linnaeus’s Mouse Opossum in Guiana is 8-4 young, but litters of up to eleven young have been recorded. Young are born measuring c.10 mm. In central Brazil, reproductively active females were collected during the dry season. One female was captured with six pouch young in September, and two other females with signs of recent lactation were captured in August and September.

Activity patterns. There is no specific information for this species, but Linnaeus’s Mouse Opossum is nocturnal.

Movements, Home range and Social organization. Linnaeus’s Mouse Opossum uses understory, the ground, and very rarely canopy. In French Guiana,it almost exclusively used stratum below 5 m, very rarely going above that height, regardless of the diameter of the tree or branch used. In Venezuela, 48% of 71 individuals were caught on the ground and 52% on logs, trees, or houses, and in south-eastern Brazil, they were captured more frequently in understory than on the ground. Densities in French Guiana are 55 ind/km?, with a range of 20-100 ind/km?.

Status and Conservation. Classified as Least Concern on The IUCN Red List. Linnaeus’s Mouse Opossum has a wide distribution and presumably a large population;it is tolerant of habitat modification and human presence and occurs in several protected areas throughout its distribution. This most recent IUCN assessment was made prior to taxonomic revision that elevated some ofits former subspecies to full species status. Conservation status of all opossumsis being reassessed by the IUCN New World Marsupial Specialists Group, butit is unlikely that the status will be altered for Linnaeus’s Mouse Opossum.

Bibliography. Adler et al. (2012), Argot (2001, 2002, 2003), Astua (2010), Atramentowicz (1986, 1988), Carvalho et al. (2002), Catzeflis (2012), Charles-Dominique (1983), Charles-Dominigue et al. (1981), Creighton & Gardner (2007b), Dadalto & Caldara (2013), Emmons & Feer (1997), Faria, de Oliveira & Bonvicino (2013), Fleck & Harder (1995), Grand (1983), Gutiérrez et al. (2010), Hannibal & Caceres (2010), Hershkovitz (1992a), Julien-Laferriere (1991), Lambert et al. (2005), Lima (2004), Martinelli & Nogueira (1997), de Muizon & Argot (2003), Palma, A.R.T. (1996), Palma, R.E. & Yates (1996), Paresque et al. (2004), Patton et al. (2000), Pereira et al. (2008), Reig et al. (1977), Rocha, R.G. et al. (2011), Rossi (2005), Santos-Filho et al. (2008), Santos et al. (2004), de Souza et al. (1990), Steiner & Catzeflis (2003, 2004), Svartman (2009), Thomas (1911), Voss etal. (2014).

Figures

65. Pygmy Opossum (Chacodelphys formosa), 66. Agricola’s Opossum (Cryptonanus agricola), 67. Chacoan Mouse Opossum (Cryptonanus chacoensis), 68. Guaiba Mouse Opossum (Cryptonanus guahybae), 69. Unduavi Mouse Opossum (Cryptonanus unduaviensis), 70. . Emilie’s. 9 Opossum.. Gracilinanus. (null), 71. Aceramarca Opossum (Gracilinanus aceramarcae), 72. Agile Opossum (Gracilinanus agilis), 73. Wood Sprite Opossum (Gracilinanus dryas), 74. Northern Gracile Opossum (Gracilinanus marica), 75. Brazilian Gracile Opossum (Gracilinanus microtarsus)

Distribution. Venezuela, the Guianas, Trinidad and Tobago Is, and C & E Brazil (including E Amazonia).