Living fossil
A popular name for a living species that looks much like its relatives in very old fossils, such as the coelacanth.
Also: relict species
Living fossil is an informal term, not a scientific category. It is used for species that belong to old lineages with few living members and look much like fossil ancestors. The coelacanth is the classic case: known only from fossils and thought to have died out about 66 million years ago, it was found alive off South Africa in 1938, and a second species was found in Indonesia in 1997. Sturgeons, gars, bichirs, lungfish and the frilled shark are often called living fossils too, though all have kept evolving.