In paleontology, a Lazarus taxon (plural taxa) is a taxon that disappears for one or more periods from the fossil record, only to appear again later. The term refers to the account in the Gospel of John, in which Jesus raised Lazarus from the dead.
Potential explanations 
Lazarus taxa are observational artifacts that appear to occur either because of (local) extinction, later resupplied, or as a sampling artifact. The fossil record is inherently imperfect (only a very small fraction of organisms become fossilized, and an even smaller fraction discovered before destruction) and contains gaps not necessarily caused by extinction, particularly when the number of individuals in a taxon is very low.
After mass extinctions, such as the Permian–Triassic extinction event, the Lazarus effect occurred for many taxa. However, there appears to be no link with the abundance of fossiliferous sites and the proportion of Lazarus taxa, nor have missing taxa been found in potential refuges. Therefore, reappearance of Lazarus taxa probably reflects the rebound after a period of extreme rarity during the aftermath of such extinctions.
Related but distinctive concepts 
An Elvis taxon is a look-alike that has supplanted an extinct taxon.
A zombie taxon is a taxon that contains specimens that have been collected from strata younger than the extinction of the taxon. Later such fossils turn out to be freed from the original seam and refossilized in a younger sediment. For example, a trilobite that gets eroded out of its Cambrian-aged limestone matrix, and reworked into Miocene-aged siltstone.
A living fossil is an extant taxon that appears to have changed so little compared to fossil remains, that it is considered identical. Living fossils may occur regularly in the fossil record, such as the lampshell Lingula.
Other living fossils however are also Lazarus taxa if these have been missing from the fossil record for substantial periods of time, such as applies for Coelacanths.
Finally, the term "Lazarus species" is applied to organisms that have been rediscovered as being still alive after having been widely considered extinct for years, whithout ever having appeared in the fossil record. In this last case, the term Lazarus taxon applied in neontology.
Reappearing fossil taxa 
- Chacoan Peccary (Catagonus wagneri), known to scientists only from fossils before its discovery in 1975.
- Coelacanth (Latimeria), a member of a subclass (Actinistia) thought to have gone extinct 65 million years ago; live specimens found in 1938.
- Nightcap Oak (Eidothea hardeniana and E. zoexylocarya), representing a genus previously known only from fossils 15 to 20 million years old, were recognized in 2000 and 1995, respectively.
- 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.
- Laotian Rock Rat (Laonastes aenigmamus), a member of a family (Diatomyidae) thought to have gone extinct 11 million years ago; found in 1996.
- Majorcan midwife toad (Alytes muletensis), described from fossil remains in 1977, living animals discovered in 1979.
- Dawn Redwood (Metasequoia), a genus of conifer, was first described as a fossil from the Mesozoic Era by Shigeru Miki in 1941, but in 1943 a small stand was discovered in China in Modaoxi by Zhan Wang.
- Monito del Monte (Dromiciops), a member of a clade (Microbiotheria) thought to have gone extinct 11 million years ago.
- Monoplacophora, a class of molluscs believed to have gone extinct in the middle Devonian Period (c. 380 million years ago) until living members were discovered in deep water off Costa Rica in 1952.
- Mountain Pygmy Possum (Burramys parvus), Australia's only truly hibernating marsupial, known originally from the fossil record and then discovered in 1966.
- Wollemi Pine (Wollemia), a species previously known only from fossils from 2 to 90 million years old representing a new genus of Araucariaceae, was discovered in 1994.
Reappearing IUCN red list species 
- Afrothismia pachyantha
- Antirhea tomentosa
- Asplundia clementinae
- Badula platyphylla
- Blunt Chaff Flower (Achyranthes mutica)
- Bulbophyllum filiforme
- Bulbostylis neglecta
- Café marron (Ramosmania rodriguesii) — Thought extinct in the 1950s but rediscovered in 1980.
- Camellia piquetiana, long known only from the 19th century herbarium specimens labeled as Thea piquetiana until it was rediscovered in Vietnam in 2003.
- Climbing Alsinidendron (Alsinidendron viscosum)
- Cyanea dunbariae
- Cyanea procera
- Eugenia bojeri
- Franciscan Manzanita (Arctostaphylos hookeri) — Thought to be extinct in the wild since 1942, rediscovered in 2009.
- Furbish's lousewort (Pedicularis furbishiae) - Canadian species identified as an extinct species in 1880, rediscovered in the 1970s.
- Jellyfish tree (Medusagyne oppositifolia)
- Mammillaria schwarzii
- Medemia argun
- Mount Diablo buckwheat (Eriogonom truncatum) — Thought extinct around 1935 but found again in 2005.
- Pittosporum tanianum
- She cabbage tree (Lachanodes arborea)
- Sicilian Fir (Abies nebrodensis)
- Takhtajania perrieri
- Turbinicarpus gielsdorfianus
- Virginia Round-leaf Birch (Betula uber)
- Discus guerinianus, a Madeiran land snail thought extinct in 1996 but found again in 1999.
- Giant Palouse earthworm (Driloleirus americanus); thought extinct in 1980s, but found again in 2006.
- Canterbury knobbed weevil (Karocolens tuberculatus), last seen in 1922 until it was rediscovered near Lake Tekapo in December 2004.
- Lord Howe Island stick insect (Dryococelus australis); thought to be extinct by 1930 — rediscovered in 2001.
- Nothomyrmecia macrops, Australian ant discovered in 1931, not seen again until 1977.
- Xylotoles costatus, New Zealand longhorn beetle, considered extinct from 1986 to 1996, found again on Chatham Islands
- Bone skipper fly (Thyreophora cynophila), first described (1794) and last seen in Central Europe (1850), before being photographed in Spain in 2009.
- Black kokanee (Oncorhynchus nerka kawamurae) Believed extinct in 1940, rediscovered in 2010
- Armoured Frog (Litoria lorica)
- Painted frog (Atelopus ebenoides marinkellei) Believed extinct 1995, rediscovered in 2006.
- Atelopus laetissimus
- Atelopus nahumae
- Israel Painted Frog (Discoglossus nigriventer)
- Isthmohyla rivularis
- Ixalotriton niger
- Large-crested toad (Bufo cristatus)
- Northern Tinker Frog (Taudactylus rheophilus)
- Philautus chalazodes
- Sumatra Toad (Bufo sumatranus)
- Telmatobufo venustus was not seen from 1899 until 1999.
- Thorius minutissimus
- Bavarian pine vole (Microtus bavaricus) - believed extinct in the 1960s, but rediscovered in 2000.
- Brazilian Arboreal Mouse (Rhagomys rufescens)
- Caspian horse - thought to be descended from Mesopotamian horses which became extinct in the 7th century, but was rediscovered in the 1960s.
- Central Rock Rat (Zyzomys pedunculatus)
- Cuban Solenodon (Atopogale cubanus), thought to have been extinct until a live specimen was found in 2003.
- Fernandina rice rat (Nesoryzomys fernandinae) — Thought extinct in 1996 (last seen 1980) but found again in late 1990s.
- Gilbert's Potoroo (Potorous gilbertii), extremely rare Australian mammal presumed extinct from the 19th century until 1994.
- Miller's grizzled langur (Presbytis hosei canicrus) Presumed extinct 2010, rediscovered 2012.
- Leadbeater's Possum (Gymnobelideus leadbeateri), thought to be extinct until 1965
- Mahogany Glider (Petaurus gracilis) which was described in 1883 and not recorded between 1886 and 1973. An expedition by the Queensland Museum in 1989 found a living population.
- New Holland Mouse (Pseudomys novaehollandiae) described by George Waterhouse in 1843, it was re-discovered in Ku-ring-gai Chase National Park, North of Sydney, in 1967.
- Philippine bare-backed fruit bat (Dobsonia chapmani)
- Santiago Galápagos Mouse (Nesoryzomys swarthi ) Thought extinct and last recorded in 1906, but was rediscovered in 1997.
- Tammar Wallaby (Macropus eugenii eugenii), this Australian subspecies was presumed extinct from 1925 until genetically matched with imported species in New Zealand in 1998.
- Woolly flying squirrel (Eupetaurus cinereus) - known only from pelts collected in Pakistan in the late 19th century, until live specimens were collected in the 1990s.
- Yellow-tailed woolly monkey (Lagothrix flavicauda)
- Arakan Forest Turtle (Heosemys depressa) was last seen in 1908 but found again in 1994.
- El Hierro Giant Lizard (Gallotia simonyi), rediscovered in 1974
- Gray's monitor (Varanus olivaceus), was described in 1845, and not seen again by scientists for 130 years
- La Gomera Giant Lizard (Gallotia bravoana), rediscovered in 1999
- La Palma Giant Lizard (Gallotia auaritae) Thought to have been extinct since 1500, but rediscovered in 2007.
- New Caledonian Crested Gecko (Rhacodactylus ciliatus)
- Terror Skink (Phoboscincus bocourti) a 50-cm-long lizard, was previously known from a single specimen captured around 1870 and was long presumed extinct. In 2003, on a tiny islet, it was rediscovered.
- Bahia Tapaculo (Eleoscytalopus psychopompus)
- Banggai Crow (Corvus unicolor) not recorded since 1884/1885, confirmed with a photograph in 2008
- Beck's Petrel (Pseudobulweria beckii), not seen between 1929 and 2007
- Berlepsch's Parotia (Parotia berlepschi)
- Bermuda Petrel or "Cahow" (Pterodroma cahow) — Thought extinct since 1620 until 18 nesting pairs were found in 1951 on an uninhabited rock outcropping in Bermuda. Bermudian David B. Wingate has devoted his life to bringing the birds back, and in the 2011-12 breeding season they passed the 100-pair mark.
- Grand Comoro scops-owl (Otus pauliani).
- Bruijn's Brush-turkey (Aepypodius bruijnii)
- Cebu Flowerpecker (Dicaeum quadricolor)
- Cone-billed Tanager (Conothraupis mesoleuca) a Tanager species that was undetected from 1938 to 2003, but was then rediscovered in gallery forest in Emas National Park.
- Cuban Kite (Chondrohierax wilsonii), confirmed with a photograph in 2009
- Edwards's Pheasant (Lophura edwardii), a Vietnamese pheasant presumed extinct from 1928 until it was rediscovered in 1998.
- Fiji Petrel (Pseudobulweria macgillivrayi), first rediscovered on land in 1983, at the sea in 2009
- Forest Owlet (Heteroglaux blewitti) — Assumed extinct in the 19th century, but rediscovered in central India in 1997.
- Golden-fronted Bowerbird (Amblyornis flavifrons)
- Ivory-billed woodpecker (Campephilus principalis) — Thought extinct circa 1987 before unconfirmed sightings in 1999, 2004, and 2006 in Arkansas and Florida.
- Jerdon's Courser (Rhinoptilus bitorquatus) — A wader from India, assumed extinct until 1986.
- Kaempfer's Woodpecker (Celeus obrieni), a Brazilian woodpecker feared extinct after no specimen had been found since its discovery in 1926. Rediscovered in 2006.
- Large-billed Reed-warbler (Acrocephalus orinus), a warbler rediscovered in Thailand in 2006, previous known only from a specimen collected in India in 1867.
- Long-legged Warbler (Trichocichla rufa)
- Madagascar Pochard (Aythya innotata), thought extinct since 1991 until a small group were spotted in 2006.
- Madagascar serpent-eagle (Eutriorchis astur) - rediscovered in 1993, sixty years since the previous sighting.
- New Zealand storm-petrel (Oceanites maorianus) Believed extinct from 1850 but sighted again in 2003.
- Night Parrot (Pezoporus occidentalis), extremely rare Australian bird presumed extinct from 1880s until 1990.
- Noisy Scrub-bird (Atrichornis clamosus)
- São Tomé Fiscal (Lanius newtoni)
- São Tomé Grosbeak (Neospiza concolor)
- Silvery Pigeon (Columba argentina), confirmed with a photograph in 2008
- Stresemann's Bristlefront (Merulaxis stresemanni)
- Takahe (Porphyrio hochstetteri) — Assumed extinct in 1898 but found again in 1948.
- Utila Chachalaca (Ortalis vetula deschauenseei), subspecies of the Plain Chachalaca from Honduras, not recorded between 1963 and 2000 and confirmed with a photograph in 2005
- White-winged Guan (Penelope albipennis)
- White-collared Kite (Leptodon forbesi)
See also 
- Elvis taxon
- List of extinct animals
- List of fossil sites (with link directory)
- Living fossil
- Signor-Lipps effect
- Zombie taxon
- Wignall, P. B.; Benton, M. J. (1999). "Lazarus Taxa and Fossil Abundance at Times of Biotic Crisis". Journal of the Geological Society 156.
- Shuker, K.P.N. (2002). The New Zoo: New and Rediscovered Animals of the Twentieth Century. House of Stratus.
- *Heuvelmans, Bernard. On The Track Of Unknown Animals. (New York: Hill and Wang, 1959.
- Naish, Darren (2008-11-24). "New, obscure, and nearly extinct rodents of South America, and... when fossils come alive". Tetrapod Zoology. Retrieved 2008-12-13.
- C.A. McGuinness (2004). Xylotoles costatus. 2006. IUCN Red List of Threatened Species. IUCN 2006. www.iucnredlist.org. Retrieved on 17 March 2007.
- Miguel Carles-Tolrá, Pablo C. Rodríguez & Julio Verdú (2010). "Thyreophora cynophila (Panzer, 1794): collected in Spain 160 years after it was thought to be extinct (Diptera: Piophilidae: Thyreophorini)". Boletín de la Sociedad Entomológica Aragonesa (S.E.A.) 46: 1–7.
- Gehrman, Rare Birds.
- Extraordinary Tale of the Bermuda Petrel and the Man Who Brought It Back from Extinction" (Boston: Beacon Press, 2012).
- Ghost Bird 2009.