Gracilinanus

Gracilinanus is a genus of opossum in the family Didelphidae. It was separated from the genus Marmosa in 1989, and has since had the genera Cryptonanus, Chacodelphys, and Hyladelphys removed from it.

== Physical description == Gracile mouse opossums, excluding the fat-tailed mouse opossum, in general, have a prehensile tail that is thin and very long. The tails of mouse opossums are naked. Mouse opossums have ears that are, both, large and naked. General opossums, including Gracilinanus species, have noses that are pointed. Another general characteristic that mouse opossum have are mammary glands. Each member of the Gracilinanus species has a dark ring that is found around each eye. The species G. microtarsus has red-brown fur on the top of the body and gray fur on the underside. In comparison with G. microtarsus, G. agilis has paler fur color. Over the years, a new species, G. ignitus, has been added to the genus. G. ignitus has a white patch on its chest. It, as well, has a light, two-tone colored tail that has only a few hairs. The fur color can be used to determine if a member of the genus is part of the G. ignitus species. G. microtarsus, G. emiliae, and G. dryas can be distinguished from G. ignitus by their tails that are only one color. One difference between G. agilis and G. ignitus is that G. agilis has a hairier tail. G. aceramarcae has naked skin compared to G. ignitus. G. emiliae is smaller than G. ignitus. G. emiliae, in general, has a very long tail. A difference between G. emiliae and the rest of the species in the genus is that it has white fur on the underside of the body and the rest of the species have a gray or brown color.