Editing Incertae sedis (section)

===Not included in an analysis===
If a formal [[phylogeny|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 phylogeny|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 [[vertebra]]e as principal characters and the taxon in question is only known from a single tooth, it would be necessary to label it ''incertae sedis''.<ref name=Matthews1973/>