What is Lazarus taxon?
In [[paleontology]], a '''Lazarus taxon''' (plural ''taxa'') is a [[taxon]] that disappears from one or more periods of the [[fossil]] record, only to appear again later. The term refers to the [[Gospel of John]], in which [[Jesus]] is claimed to have raised [[Lazarus]] from the dead. Lazarus taxa occur either because of (local) [[extinction]], later resupplied, or as a [[Sampling (statistics)|sampling artifact]]. The [[fossil]] record is imperfect (only a very small fraction of organisms become fossilized) and contains gaps not necessarily caused by extinction, particularly when the number of individuals in a taxon becomes very low. The concept was developed in [[palaeontology]] where, after a major extinction event, some groups reappear after millions of years. The usual explanation is that numbers were driven so low that their chance of fossilisation were extremely low. Then, gradually, their numbers revived. == History of the idea == In 1974 Batten pointed out that the [[Lower Triassic]] record lacked [[genera]] and [[species]] which had been present in the [[Permian]], but which reappeared 20 million years later in the [[Middle Triassic]].<ref>Batten R.L. 1973. The vississitudes of the gastropods during the interval of Guadalupian&ndash;Ladinian time.In A. Logan & L.V. Hills (eds) ''The Permian and Triassic systems and their mutual boundary''. Memoir 2, 596&ndash;607. Calgary, Canadian Society of Petroleum Geologists.</ref> Jablonski later coined the term 'Lazarus taxon' for species and genera which disappear from the fossil record, only to reappear later when conditions return to normal.<ref>Jablonski D. 1986. Background and mass extinctions: alternation of macroevolutionary regimes. ''Science'' '''231''', 129&ndash;133.</ref> == Living examples== There are some well-known examples of it happening to present-day species. Some well-known examples: [[File:Latimeria chalumnae01.jpg|thumb|250px|[[Coelacanth]] ''Latimeria chalumnae''.]] * A complete [[clade]] of [[lobe-finned fish]], the sub-class Coelacant