fossa

:  a slender, long-tailed, carnivorous mammal (Cryptoprocta ferox of the family Eupleridae) of Madagascar that has retractile claws, usually reddish-brown or sometimes black, short, thick fur, and anal scent glands <The fossa evolved on the catless island of Madagascar, where it became the ecological equivalent of a cat. With nothing else around to fill the role, the fossa became a sort of mini-leopard, hunting lemurs and other small animals in the forest at night. — Fiona Sunquist>

:  an anatomical pit, groove, or depression <the temporal fossa of the skull> <the fossa in the liver for the gallbladder>