Incertae sedis

Incertae sedis is a term used in the field of taxonomy to refer to a taxonomic group where its broader relationships are unknown or undefined. The term is Latin for "of uncertain placement" and is often used for taxa when the phylogenetic relationships are unclear.

Definition

The term Incertae sedis (Latin for 'of uncertain placement') is often used in the classification of organisms where the taxonomic position is uncertain or undefined. It is used in situations where further research is needed to determine the phylogenetic relationships and classification of a particular group of organisms.

Usage in Taxonomy

In taxonomy, the term Incertae sedis is used to denote a taxonomic group where its broader relationships are unknown or undefined. This can occur when the characteristics of the group do not match the criteria used to define the existing taxa, or when the phylogenetic relationships are unclear. The term is often used in the context of phylogenetic trees, where it denotes a group of organisms that cannot be placed in any particular branch of the tree.

Examples

Examples of taxa that are currently classified as Incertae sedis include the bacterial phylum Armatimonadetes, the fungal class Geoglossomycetes, and the animal phylum Placozoa. These groups are all characterized by a lack of clear phylogenetic relationships with other groups, and their classification as Incertae sedis reflects the current state of knowledge in their respective fields.

See also

• Taxonomy (biology)
• Phylogenetics
• Cladistics

References

• 
  California Condor
• 
  Plumalina plumaria fossil
• 
  Varanops illustration