1 Examples 2 In formal nomenclature 3 Reason for use
3.1 Poor description 3.2 Not included in an analysis 3.3 Controversy
4 In zoological nomenclature 5 See also 6 References 7 External links
The fossil plant
Paradinandra suecica could not be assigned to any
family, but was placed incertae sedis within the order
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
Reason for use
This excerpt from a 2007 scientific paper about crustaceans of the
...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 phylogenetic analysis is conducted that does not include a certain taxon, the authors might choose to label the taxon incertae sedis instead of guessing its placement. This is particularly common when 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. 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. In zoological nomenclature In botany, a name is not validly published if it is not accepted by the author in the same publication.Article 36.1 In zoology, a name proposed conditionally may be available under certain conditions.Articles 11 and 15 For uncertainties at lower levels, the system of open nomenclature suggests that question marks be used to denote a questionable assignment. For example, if a new species was given the 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. 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. See also
Glossary of scientific naming Nomen dubium, a name of unknown or doubtful application Species inquirenda, a species that in the opinion of the taxonomist requires further investigation Wastebasket taxon Sui generis (Biology)
^ a b "Glossary". International Code of Zoological Nomenclature.
International Commission on Zoological Nomenclature. Retrieved
^ "Frequently Asked Questions". PLANTS database. United States
Department of Agriculture. Retrieved 2011-06-12.
^ Allaby, M. (1999). A Dictionary of Zoology. Oxford University Press.
p. 704. Retrieved 2013-01-05.
^ a b c d e f S. C. Matthews (1973). "Notes on open nomenclature and
synonymy lists" (PDF). Palaeontology. 16 (4): 713–719. Archived from
the original (PDF) on 2011-07-27.
^ Jürg Schönenberger; Else Marie Friis (March 2001). "
The dictionary definition of incertae sedis at Wiktionary
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