حفرية حية

A living fossil is a living species (or clade) of organism that appears to be similar to a species otherwise known only from fossils. Normally the similarity is only a superficial physical resemblance between two different species, one extinct, the other extant. Living fossil is a term mostly used in the lay media, sometimes wrongly to imply a lack of evolution, and scientific investigations have repeatedly discredited claims that these species do not change.

شوكيات الجوف كان يعتقد انها انقرضت 65, حتى عثر على عينة حية تنتمي إلى رتبة اكتشف في عام 1938.

Overview

Fossil and living ginkgos

170 million-year-old fossil Ginkgo leaves

Living Ginkgo biloba plant

These species have a fossil record indicating they have survived major extinction events, generally retain low taxonomic diversities today, having no close living relatives. A species that successfully radiates (forming many new species after a possible genetic bottleneck) has become too successful to be considered a living fossil.

A subtle difference is sometimes made between a "living fossil" and a "Lazarus taxon". A Lazarus taxon is a taxon (either one species or a group of species) that suddenly reappears, either in the fossil record or in nature (i.e., as if the fossil had "come to life again"), while a living fossil is a species that (seemingly) has not changed during its very long lifetime (i.e., as if the fossil species has always lived).