Incertae sedis

Source: Wikipedia, the free encyclopedia.

Aves until the recognition of the new order Cathartiformes
.
New York State, US. Workers usually assign this organism to the hydrozoans (phylum Cnidaria, class Hydrozoa) or the gorgonarians (phylum Cnidaria, class Anthozoa, order Gorgonaria), but it is probably safest to refer to it as incertae sedis.[1]
Amniota
incertae sedis.

Incertae sedis (

Latin for 'of uncertain placement')[2] or problematica is a term used for a taxonomic group where its broader relationships are unknown or undefined.[3] Alternatively, such groups are frequently referred to as "enigmatic taxa".[4] In the system of open nomenclature, uncertainty at specific taxonomic levels is indicated by incertae familiae (of uncertain family), incerti subordinis (of uncertain suborder), incerti ordinis (of uncertain order) and similar terms.[5]

Examples

In formal nomenclature

When formally naming a taxon, uncertainty about its taxonomic classification can be problematic. The International Code of Nomenclature for algae, fungi, and plants, stipulates that "species and subdivisions of genera must be assigned to genera, and infraspecific taxa must be assigned to species, because their names are combinations", but ranks higher than the genus may be assigned incertae sedis.[14]

Reason for use

Poor description

This excerpt from a 2007 scientific paper about crustaceans of the Kuril–Kamchatka Trench and the Japan Trench describes typical circumstances through which this category is applied in discussing:[15]

...the removal of many genera from new and existing families into a state of incertae sedis. Their reduced status was attributed largely to poor or inadequate descriptions but it was accepted that some of the vagueness in the analysis was due to insufficient character states. It is also evident that a proportion of the characters used in the analysis, or their given states for particular taxa, were inappropriate or invalid. Additional complexity, and factors that have misled earlier authorities, are intrusion by extensive

homoplasies, apparent character state reversals and convergent evolution
.

Not included in an analysis

If a formal

molecular phylogenies are generated, since tissue for many rare organisms is hard to obtain. It is also a common scenario when fossil taxa are included, since many fossils are defined based on partial information. For example, if the phylogeny was constructed using soft tissue and vertebrae as principal characters and the taxon in question is only known from a single tooth, it would be necessary to label it incertae sedis.[5]

Controversy

If conflicting results exist or if there is not a consensus among researchers as to how a taxon relates to other organisms, it may be listed as incertae sedis until the conflict is resolved.[5]

Phylogenetic vs. nomenclatural uncertainty

The term incertae sedis refers to uncertainty about phylogenetic position of a taxon, which may be expressed, among others, by using a question mark after or before a taxon name. This should be distinguished from the situation where either it is uncertain how to use a name, often because the types have been lost (nomen dubium, species inquirenda), or whether a poorly preserved specimen should be included within a given species or genus, which is often expressed using a 'cf.' (from Latin confer, compare, before a taxon name); such a convention is especially widespread in palaeontology.[16]

In zoological nomenclature

In zoological nomenclature, "incertae sedis" is not a nomenclatural term at all per se, but is used by taxonomists in their classifications to mean "of uncertain taxonomic position".

specific epithet album by Anton and attributed with uncertainty to Agenus, it could be denoted "Agenus? album Anton (?Anton)"; the "(?Anton)" indicates the author that assigned the question mark.[5] So if Anton described Agenus album, and Bruno called the assignment into doubt, this could be denoted "Agenus? album (Anton) (?Bruno)", with the parentheses around Anton because the original assignment (to Agenus) was modified (to Agenus?) by Bruno.[5] This practice is not included in the International Code of Zoological Nomenclature, and is used only by paleontologists.[5]

See also

References

  1. ^ "Plumalina plumaria". JSJ Geology. Retrieved 20 January 2021.
  2. ^ a b c "Glossary". International Code of Zoological Nomenclature. International Commission on Zoological Nomenclature. Retrieved 12 June 2011.
  3. ^ "Frequently Asked Questions". PLANTS database. United States Department of Agriculture. Retrieved 12 June 2011.
  4. ^ Allaby, M. (1999). A Dictionary of Zoology. Oxford University Press. p. 704. Retrieved 5 January 2013.
  5. ^ a b c d e f g S. C. Matthews (1973). "Notes on open nomenclature and synonymy lists" (PDF). Palaeontology. 16 (4): 713–719. Archived from the original (PDF) on 27 July 2011.
  6. PMID 11250825
    .
  7. S2CID 39189634
    .
  8. American Ornithologists' Union. Archived from the original
    on 10 October 2007. Retrieved 15 October 2007.
  9. American Ornithologists' Union. Archived from the original
    on 2 March 2009. Retrieved 12 June 2011.
  10. PMID 26064613
    .
  11. S2CID 3592799
    .
  12. PMID 23024290
    .
  13. ISBN 978-1-4020-9211-4
    .
  14. ^
    ISBN 978-3-87429-425-6
    . Retrieved 28 July 2013.
  15. doi:10.11646/zootaxa.1599.1.8
    .
  16. ^ Bengtson, Peter (January 1988). "Open Nomenclature" (PDF). Palaeontology. 1 (31): 223–227.

External links

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