Lazarus taxon

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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 New Testament story of Lazarus, whom Jesus miraculously raised from the dead. Lazarus taxa are observational artifacts that appear to occur either because of (local) extinction, later resupplied, or as a sampling artifact. If the extinction is conclusively found to be total (global or worldwide) and the supplanting species is not a lookalike (an Elvis species), the observational artifact is overcome. The fossil record is inherently imperfect and contains gaps not necessarily caused by extinction, particularly when the number of individuals in a taxon becomes very low. If these gaps are filled by new fossil discoveries, a taxon will no longer be classified as a Lazarus taxon.

The terms "Lazarus effect" or "Lazarus species" have also found some acceptance in neontology — the study of extant organisms, as contrasted with paleontology — as an organism that is rediscovered alive after having been widely considered extinct for years (a recurring IUCN Red List species for example). Examples include the Wollemi pine, the Jerdon's courser, the ivory-billed woodpecker, the Mahogany Glider and the takahe, a flightless bird endemic to New Zealand. It should be noted, however, that being "extinct" strongly relates to the sampling intensity and the whims of the IUCN, and that such a period of apparent extinction is too short for species to be designated as "Lazarus taxa" (in its paleontological meaning).

Lazarus taxa that reappear in nature after being known only as old enough fossils can be seen as an informal subcategory of the journalist's "living fossils", because a taxon cannot become globally extinct and reappear. If the original taxon went globally extinct, the new taxon must be an Elvis taxon. On the other hand, all species "correctly considered living fossils" (with all conditions fulfilled, living and found through a considerable part of the geologic timescale) cannot be Lazarus taxa.

1 Reappearing species
- 1.1 Reappearing IUCN red list species
- 1.2 Reappearing fossil taxa
2 Other Notable Biota
3 See also

[edit] Reappearing species

[edit] Reappearing IUCN red list species

Madeiran land snail (Discus guerinianus) — Thought extinct in 1996 but found again in 1999.
Fernandina rice rat (Nesoryzomys fernandinae) — Thought extinct in 1996 (last seen 1980) but found again in late 1990s.
Ivory-billed woodpecker (Campephilus principalis) — Thought extinct in 1944 before an unconfirmed sighting in 1999, and possible rediscovery in 2005 (though disputed).
Lord Howe Island stick insect (Dryococelus australis).
Bavarian pine vole (Microtus bavaricus).
Mount Diablo buckwheat (Eriogonom truncatum) — Thought extinct around 1935 but found again in 2005.
Jerdon's Courser (Rhinoptilus bitorquatus) — A wader from India, assumed extinct until 1986.
Madagascar serpent-eagle (Eutriorchis astur).
Grand Comoro scops-owl (Otus pauliani).
Furbish's lousewort (Pedicularis furbishiae).
Takahe (Porphyrio hochstetteri) — Assumed extinct in 1898 but found again in 1948.
New Zealand storm-petrel — Believed extinct from 1850 but sighted again in 2003.
Painted frog (Atelopus ebenoides marinkellei) Believed extinct 1995, rediscovered in 2006.
Forest Owlet (Heteroglaux blewitti) — Assumed extinct in the 19th century, but rediscovered in central India in 1997.
Woolly flying squirrel (Eupetaurus cinereus)
Gilbert's Potoroo (Potorous gilbertii), extremely rare Australian mammal presumed extinct from 1800s until 1994.
Night Parrot (Pezoporus occidentalis), extremely rare Australian bird presumed extinct from 1880s until 1990.
New Holland Mouse (Pseudomys novaehollandiae) was first described by George Waterhouse in 1843, it vanished from view for over a century before its rediscovery in Ku-ring-gai Chase National Park north of Sydney, in 1967.
Tammar Wallaby (Macropus eugenii eugenii), this Australian subspecies was presumed extinct from 1925 until genetically matched with imported species in New Zealand in 1998.
Edwards's Pheasant (Lophura edwardii), a Vietnamese pheasant presumed extinct from 1928 was rediscovered in 1998.
Cuban Solenodon (Atopogale cubanus), thought to have been extinct until a live specimen was found in 2003.
Giant Palouse earthworm (Driloleirus americanus); thought extinct in 1980s, but found again in 2006.

[edit] Reappearing fossil taxa

Image:Latimeria chalumnae01.jpg

Coelacanth (Latimeria), a member of a clade (Coelacanthimorpha) thought to have gone extinct 80 million years ago; found in 1938.
Laotian Rock Rat (Laonastes aenigmamus), a member of a clade (Diatomyidae) thought to have gone extinct 11 million years ago; found in 1996.
Monito del Monte (Dromiciops), a member of a clade (Microbiotheria) thought to have gone extinct 11 million years ago.
Lazarussuchus, an Oligocene member of a clade of freshwater reptiles (Choristodera) thought to have gone extinct at the end of the Mesozoic. As Lazarussuchus is thought to be outside the clade including other choristoderans, it may indicate a ghost lineage going back to the Late Triassic, a span of over 170 million years.
Gracilidris, a genus of dolichoderine ants thought to have gone extinct 15-20 million years ago was found in Paraguay, Brazil, and Argentina and described in 2006.

[edit] Other Notable Biota

This is a list of plants and animals that may not qualify as a Lazarus taxon or a living fossil, but are noteworthy due to retaining most of their features from the distant past or being a rather isolated representative of a limited branch of evolution.