paleontology Paleontology, also spelled as palaeontology or palæontology, is the scientific study of the life of the past, mainly but not exclusively through the study of fossils. Paleontologists use fossils as a means to classify organisms, measure ge ...

, an Elvis taxon (plural ''Elvis taxa'') is a

taxon In biology, a taxon (back-formation from ''taxonomy''; : taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular name and ...

that has been misidentified as having re-emerged in the

fossil record A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

after a period of presumed

extinction Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

, but is not actually a descendant of the original taxon, instead having developed a similar morphology by

convergent evolution Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last comm ...

. This implies that the extinction of the original taxon is real, and one taxon containing specimens from before and after the extinction would be

polyphyletic A polyphyletic group is an assemblage that includes organisms with mixed evolutionary origin but does not include their most recent common ancestor. The term is often applied to groups that share similar features known as Homoplasy, homoplasies ...

Etymology

The term "Elvis taxon" was coined by D. H. Erwin and M. L. Droser in a 1993 paper to distinguish descendant from non-descendant taxa:

Related but distinctive concepts

By contrast, a

Lazarus taxon 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 either in later fossil records, or as actual living organisms, and often in isolated, obscure, ...

is one that really is a descendant of the original taxon, and highlights

transitional fossil A transitional fossil is any fossilized remains of a life form that exhibits traits common to both an ancestral group and its derived descendant group. This is especially important where the descendant group is sharply differentiated by gross ...

records, which might be found later. A

zombie taxon In paleontology, a zombie taxon (plural ''zombie taxa'') or the zombie effect refers to a fossil that was washed out of sediments and re-deposited in rocks and/or sediments millions of years younger. That basic mistake in the interpretation of th ...

has been considered a

because it has been collected from younger strata, but it later turns out to be a fossil that was freed from the original seam and was refossilized in a sediment of a younger age. An example is a

trilobite Trilobites (; meaning "three-lobed entities") are extinction, extinct marine arthropods that form the class (biology), class Trilobita. One of the earliest groups of arthropods to appear in the fossil record, trilobites were among the most succ ...

that gets eroded out of its

Cambrian The Cambrian ( ) is the first geological period of the Paleozoic Era, and the Phanerozoic Eon. The Cambrian lasted 51.95 million years from the end of the preceding Ediacaran period 538.8 Ma (million years ago) to the beginning of the Ordov ...

-aged limestone matrix and reworked into

Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

-aged siltstone.Archer, Michael, Suzanne J. Hand, and Henk Godthelp. Australia's lost world: prehistoric animals of Riversleigh. Indiana University Press, 2000.

Examples

*'' Rhaetina gregaria'', one of the most common Late Triassic

brachiopod Brachiopods (), phylum (biology), phylum Brachiopoda, are a phylum of animals that have hard "valves" (shells) on the upper and lower surfaces, unlike the left and right arrangement in bivalve molluscs. Brachiopod valves are hinged at the rear e ...

species, has been regarded as a survivor that ranges across the Triassic-Jurassic boundary into the Early Jurassic. The external morphology of specimens from before and after the

Triassic–Jurassic extinction event The Triassic–Jurassic (Tr-J) extinction event (TJME), often called the end-Triassic extinction, marks the boundary between the Triassic and Jurassic periods, . It represents one of five major extinction events during the Phanerozoic, profoundly ...

were initially thought to be identical. Study of the internal features of the early

Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately 143.1 Mya. ...

material showed that it was actually quite distinct from the

Triassic The Triassic ( ; sometimes symbolized 🝈) is a geologic period and system which spans 50.5 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.4 Mya. The Triassic is t ...

specimens, and should be assigned to the genus '' Lobothyris'' as '' L. subgregaria''. *The flightless bird Aldabra rail became extinct approximately 136,000 years ago following

sea level rise The sea level has been rising from the end of the last ice age, which was around 20,000 years ago. Between 1901 and 2018, the average sea level rose by , with an increase of per year since the 1970s. This was faster than the sea level had e ...

and the total inundation of the island of

Aldabra Aldabra, the world's second-largest coral atoll (the largest is Kiritimati), is located east of the continent of Africa. It is part of the Aldabra Group of islands in the Indian Ocean that are part of the Outer Islands (Seychelles), Outer Islands ...

it inhabited. Fossil evidence suggests this species reappeared approximately 100,000 years ago when sea levels dropped and related species reinhabited the island, from which the modern white-throated rail evolved, where it is found to the present day.

References

{{reflist Extinction Phylogenetics

Taxon In biology, a taxon (back-formation from ''taxonomy''; : taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular name and ...

Etymology

Related but distinctive concepts

Examples

See also

References