Anderson's mouse opossum  (Marmosa andersoni)

Only seven individuals of this small marsupial have ever been found, all from a small region of southern Peru (2) (3). Anderson's mouse opossum is a Marmosa, or slender mouse opossum, named for their similarity in appearance to mice. The dark grey fur on the upper parts is relatively long and tipped with reddish-brown, whist the underparts are paler. The hair on the cheeks and chin is cream coloured, and prominent black rings surround the eyes (3). Anderson's mouse opossum has large thin ears, providing acute hearing (5). The tail, which is longer than the head and body, is furry at the base, with bristles that become longer and more slender towards the tip (3). Each foot has five digits and the big toe on the hindfoot is opposable, which, along with its prehensile (grasping) tail, makes Anderson's mouse opossums well-adapted for a life in the trees (5)