Wastebasket taxon

classification of organisms that do not fit in other classifications

A wastebasket taxon [1][2][3] is a term used by biologists for a taxon which has organisms that do not fit anywhere else.

Antelopes are assorted groups of bovids that are not goats, sheep or cattle.

Species or groups are put in the wastebasket taxon when they do not fit into one of the regular taxa. Regular taxa are supposed to be monophyletic. By definition, wastebasket taxa are either paraphyletic or polyphyletic. Their name may still be very useful to biologists, because its members may be an important evolutionary grade. Antelopes are a group which is ecologically very important, and have many similar features. However, they are not monophyletic. Species are called 'antelopes' if they look like one.

Invertebrates are often called the "everything-else" category, meaning all animals without backbones. Little-known fossil groups are sometimes later found to be wastebasket taxa. The crocodile-like Triassic group Rauisuchia is an example.[4]

Loosely related animals often look rather alike. This is because they adapt to similar environments. This leads to convergent evolution.


  1. or dustbin taxon or catch-all taxon
  2. Hallam A. & Wignall P.B. (1997). Mass extinctions and their aftermath. Oxford: Oxford University Press. p. 107. ISBN 978-0-19-854916-1.
  3. Monks N. (2002). "Cladistic analysis of a problematic ammonite group: the Hamitidae (Cretaceous, Albian-Turonian) and proposals for new cladistic terms". Palaeontology. 45 (4): 689–707. doi:10.1111/1475-4983.00255. S2CID 85777108.
  4. Nesbitt, S. J. (2003). "Arizonasaurus and its implications for archosaur divergence". Proceedings of the Royal Society B. 270 (Suppl. 2): S234–S237. doi:10.1098/rsbl.2003.0066. PMC 1809943. PMID 14667392. Full free text.