Incertae sedis
A term for taxa with unknown or undefined broader relationships.
Last updated
In zoological nomenclature, the term is used by taxonomists in their classifications to mean "of uncertain taxonomic position".[1] Groups in this situation are often called "enigmatic taxa" as an alternative description.[2]
Quick Facts
- Field
- Taxonomy, biological nomenclature
- Usage
- Formal and informal taxonomic classification
- Related terms
- Incertae familiae
- incerti subordinis
- incerti ordinis
- problematica
- enigmatic taxa
Facts from the source article.
Key facts and history
The International Code of Nomenclature for algae, fungi, and plants stipulates that ranks higher than the genus may be assigned incertae sedis.[3] In zoological nomenclature, "incertae sedis" is not a nomenclatural term per se.[1] The term refers to uncertainty about phylogenetic position, which may be expressed by using a question mark after or before a taxon name.[4] The 2022 "Outline of Fungi and fungus-like taxa" reported about 3,185 genera as incertae sedis.[5]
When a formal phylogenetic analysis omits a particular taxon, researchers may designate it incertae sedis rather than speculate about its placement.[6] Fossil taxa also commonly receive this label, as many fossils are known only from incomplete remains.[6] A taxon may be placed as incertae sedis when research yields contradictory findings or when no agreement exists among scientists about its relationships, pending resolution of the disagreement.[6]
What the research sources say
The International Code of Nomenclature for algae, fungi, and plants is the set of rules governing scientific naming of organisms traditionally treated as algae, fungi, or plants.[7]
References
- Wikipedia, "Incertae sedis" (CC BY-SA 4.0), which cites: "Glossary", International Code of Zoological Nomenclature; "International Code of Nomenclature for algae, fungi, and plants (Melbourne Code) adopted by the Eighteenth International Botanical Congress Melbourne, Australia, July 2011", A.R.G. Gantner Verlag KG, 2012; "Glossary", International Code of Zoological Nomenclature; S. C. Matthews, "Notes on open nomenclature and synonymy lists", Palaeontology, 1973, p. 713–719; S. C. Matthews, "Notes on open nomenclature and synonymy lists", Palaeontology, 1973, p. 713–719; S. C. Matthews, "Notes en.wikipedia.org
- Wikipedia, "Incertae sedis" (CC BY-SA 4.0), which cites: "Glossary", International Code of Zoological Nomenclature; "Frequently Asked Questions", PLANTS database; Allaby, "A Dictionary of Zoology", Oxford University Press, 1999, p. 704; S. C. Matthews, "Notes on open nomenclature and synonymy lists", Palaeontology, 1973, p. 713–719 (we also read that source) en.wikipedia.org
- Wikipedia, "Incertae sedis" (CC BY-SA 4.0), which cites: "International Code of Nomenclature for algae, fungi, and plants (Melbourne Code) adopted by the Eighteenth International Botanical Congress Melbourne, Australia, July 2011", A.R.G. Gantner Verlag KG, 2012 (we also read that source) en.wikipedia.org
- Wikipedia, "Incertae sedis" (CC BY-SA 4.0), which cites: Bengtson, "Open Nomenclature", Palaeontology, January 1988, p. 223–227 (original not read by us) en.wikipedia.org
- Wikipedia, "Incertae sedis" (CC BY-SA 4.0), which cites: Hyde, "The 2024 Outline of Fungi and fungus-like taxa", Mycosphere, 2024, p. 5146–6239 [5165–5168] (original not read by us) en.wikipedia.org
- Wikipedia, "Incertae sedis" (CC BY-SA 4.0), which cites: S. C. Matthews, "Notes on open nomenclature and synonymy lists", Palaeontology, 1973, p. 713–719 (original not read by us) en.wikipedia.org
- "International Code of Nomenclature for algae, fungi, and plants (Melbourne Code) adopted by the Eighteenth International Botanical Congress Melbourne, Australia, July 2011", A.R.G. Gantner Verlag KG, 2012. facts only, no text reused. iapt-taxon.org
Each numbered sentence above was checked against the source it cites before publication. Sentences citing Wikipedia adapt text from the English Wikipedia article Incertae sedis (contributors), used under CC BY-SA 4.0; this entry is available under the same licence. Other sources were used for facts only; no text or images are copied from them.
More in Taxonomy & Evolution
Sources
Compiled from Wikipedia and the sources listed below. Text from Wikipedia is available under CC BY-SA 4.0; this entry is adapted from it.
- Wikipedia: Incertae sedis (CC BY-SA 4.0).
- Word definitions: the Codexery glossary, each quoted from its Wikipedia article.
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