Living fossil

A living fossil is an extant taxon that closely resembles organisms otherwise known only from the fossil record. To be considered a living fossil, the fossil species must be old relative to the time of origin of the extant clade. Living fossils commonly are species-poor lineages, but they need not be. Living fossils exhibit stasis over geologically long time scales. Popular literature may wrongly claim that a 'living fossil' has undergone no significant evolution since fossil times, with practically no molecular evolution or morphological changes. Scientific investigations have repeatedly discredited such claims. The minimal superficial changes to living fossils are mistakenly declared the absence of evolution, but they are examples of stabilizing selection, which is an evolutionary process—and perhaps the dominant process of morphological evolution.