Lazarus taxon
Encyclopedia : L : LA : LAZ : 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 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, and the Takahe, a flightless bird endemic to New Zealand. It should be noted however, that "being extinct" strongly relates to the sampling intensity, the whims of the IUCN, and that the period of apparent extinction is too short 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 a lookalike of the old 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.
Reappearing species
Reappearing red list species
- Madeiran land snail (Discus guerinianus) — Thought extinct in 1996 — Found again in 1999
- Fernandina rice rat (Nesoryzomys fernandinae) — Thought extinct in 1996 (last seen 1980) — Found again in late 1990s
- Ivory-billed Woodpecker (Campephilus principalis) — Thought extinct in 1944 — Unconfirmed sighting in 1999, and possible rediscovery in 2005.
- Lord Howe Island stick insect (Dryococelus australis)
- Bavarian pine vole (Microtus bavaricus)
- Mount Diablo buckwheat (Eriogonom truncatum) — Thought extinct around 1935 — Found again in 2005
- Jerdon's Courser (Rhinoptilus bitorquatus) 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 — Found again in 1948.
- New Zealand Storm-petrel — Believed extinct from 1850 — Sighted again in 2003.
- Painted Frog (Atelopus ebenoides marinkellei) Believed extinct 1995, rediscovered 2006.
Reappearing fossil taxa
- 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 ant thought to have gone extinct 15-20 million years ago was found in Paraguay, Brazil, and Argentina and described in 2006.
See also
From Wikipedia, the Free Encyclopedia. Original article here. Support Wikipedia by contributing or donating.
All text is available under the terms of the GNU Free Documentation License See Wikipedia Copyrights for details.