living fossil A member of a living animal or plant species that is almost identical to species known from the fossil record (not the recent fossil record), i.e. they have changed very little over a long period. For example, Latimeria chalumnae (coelacanth) is close to Late Palaeozoic genera; Xiphosura species (horseshoe crabs) are close to Middle Palaeozoic genera; Tapirus pinchaque (Andean tapir) is close to a Miocene species; and Sphenodon (tuatara) has changed little since the early Mesozoic. The dawn redwood (Metasequoia glyptostroboides), a deciduous coniferous tree found growing in China in 1948, had been known previously only as fossils in America, from which it differs little; it is now widely cultivated as an ornamental. Note, however, that none of these species is identical to any fossil taxon; evolution has been slow, but not absent.

living fossil A member of a living species of animals that are almost identical to species known from the fossil record (not the recent fossil record); i.e. that have changed very little over a long period. For example, Latimeria chalumnae (coelacanth) is close to Late Palaeozoic genera; Xiphosura species (horseshoe crab) are close to Middle Palaeozoic genera; and Tapirus pinchaque (Andean tapir) is close to a Miocene species. Note, however, that none of these species is identical to any fossil taxon; evolution has been slow, but not absent.

living fossil An organism that has persisted, essentially unchanged, since its first appearance. For example, Lingula (a brachiopod) has remained much the same since Ordovician times and Sphenodon (tuatara) since the early Mesozoic.

living fossil Any organism whose closest relatives are extinct and that was once itself thought to be extinct. An example is the coelacanth, a primitive fish that was common in the Devonian era, the first recent living specimen of which was discovered in 1938.