The Isthmian mouse opossum (Marmosa isthmica) is a species of opossum in the family Didelphidae found in Colombia, Ecuador, and Panama.Fiona A. Reid, A field guide to the mammals of Central America & Southeast Mexico (OUP USA, 2009), p. 50

Foraging along branches and vines for fruit and insects, with the help of a prehensile tail, M. isthmica was formerly considered a subspecies of Robinson's mouse opossum (Marmosa robinsoni) and is supposed to be similar to it in habit, but following Rossi (2005) it is now deemed a species.

In 1935 in the Panama Canal Zone, Enders observed Marmosa isthmica to build nests with leaves in a nestbox fixed to a tree.Papéis Avulsos de Zoologia: vol. 41 (1999), Issues 1-14, p. 177

Notes

References Gardner, A. L. Mammals of South America, Volume 1: Marsupials, Xenarthrans, Shrews, and Bats. University of Chicago Press. 2008. pg. 669 (see p. 59).