Incertae sedis
term to indicate an uncertain taxonomic position
Incertae sedis (Latin for 'of uncertain placement') or problematica is a term used for a taxonomic group whose broader relationships are unknown or undefined. Alternatively, such groups are frequently referred to as "enigmatic taxa". 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.
Examples
The fossil plant Paradinandra suecica could not be assigned to any family, but was placed incertae sedis within the order Ericales when described in 2001.
The fossil Gluteus minimus, described in 1975, could not be assigned to any known animal phylum. The genus is therefore incertae sedis within the kingdom Animalia.
While it was unclear to which order the New World vultures (family Cathartidae) should be assigned, they were placed in Aves incertae sedis. It was later agreed to place them in a separate order, Cathartiformes.
Bocage's longbill, Motacilla bocagii, previously known as Amaurocichla bocagii, is a species of passerine bird that belongs to the superfamily Passeroidea. Since it was unclear to which family it belongs, it was classified as Passeroidea incertae sedis, until a 2015 phylogenetic study placed it in Motacilla of Motacillidae.
The public source identifies “Incertae sedis” as term to indicate an uncertain taxonomic position. This brief keeps that definition visible, then builds a research path around Incertae, sedis and term.
Why this record matters
A short description can identify a subject without explaining its stakes. For “Incertae sedis”, the useful work is to connect “term to indicate an uncertain taxonomic position” to the records capable of establishing context and consequence.
Named sources, stable identifiers and responsible institutions provide the strongest route from overview to verifiable evidence. The source revision retrieved here is dated May 30, 2026. The linked authority identifier is Q235536. None of the 0 selected statements returned an explicit reference. The first chronological checks are 2001, 1975 and 2015.
Overview language is designed for orientation and should not be treated as a substitute for the evidence cited beneath it. The source lead contains qualifying language; that uncertainty should survive quotation, summary and reuse. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.
How to read it
Use the entry as an orientation point, then follow its citations and revision history. Names, dates and institutional relationships should be checked against the original record.
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This entry incorporates text from “Incertae sedis” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.