In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispecific" or "monospecific" is sometimes preferred. In botanical nomenclature, a monotypic genus is a genus in the special case where a genus and a single species are simultaneously described. In contrast an oligotypic taxon contains more than one but only a very few subordinate taxa.
Just as the term monotypic is used to describe a taxon including only one subdivision, the contained taxon can also be referred to as monotypic within the higher-level taxon, e.g. a genus monotypic within a family. Some examples of monotypic groups are:
- In the order Amborellales, there is only one family, Amborellaceae and there is only one genus, Amborella, and in this genus there is only one species, namely Amborella trichopoda.
- The flowering plant Breonadia salicina is the only species in the monotypic genus Breonadia.
- The family Cephalotaceae includes only one genus, Cephalotus, and only one species, Cephalotus follicularis – the Albany pitcher plant.
- The division Ginkgophyta is monotypic, containing the single class Ginkgoopsida. This class is also monotypic, containing the single order Ginkgoales.
- Flowering plant Nandina domestica is the only species in the genus Nandina.
- The madrone butterfly is the only species in the monotypic genus Eucheira. However, there are two sub-species of this butterfly, E. socialis socialis and E. socialis westwoodi, which means the species E. socialis is not monotypic.
- Delphinapterus leucas or the "beluga whale" is the only member of its genus and lacks subspecies to speak of.
- Dugong dugongis the only species in the monotypic genus Dugong.
- Homo sapiens (humans) are monotypic as they have too little genetic diversity to harbor any living subspecies.
- The narwhal is a medium sized cetacean that is the only member of the monotypic genus Monodon.
- The platypus is the only member of the monotypic genus Ornithorhynchus.
- Ozichthys albimaculosus, the cream-spotted cardinalfish, found in tropical Australia and southern New Guinea, is the type species of the monotypic genus Ozichthys.
- The bearded reedling is the only species in the monotypic genus Panurus, which is the only genus in the monotypic family Panuridae.
- Mayr E, Ashlock PD. (1991). Principles of Systematic Zoology (2nd ed.). McGraw-Hill. ISBN 0-07-041144-1
- McNeill, J.; Barrie, F.R.; Buck, W.R.; Demoulin, V.; Greuter, W.; Hawksworth, D.L.; Herendeen, P.S.; Knapp, S.; Marhold, K.; Prado, J.; Reine, W.F.P.h.V.; Smith, G.F.; Wiersema, J.H.; Turland, N.J. (2012). "Article 38". International Code of Nomenclature for algae, fungi, and plants (Melbourne Code) adopted by the Eighteenth International Botanical Congress Melbourne, Australia, July 2011. Vol. Regnum Vegetabile 154. A.R.G. Gantner Verlag KG. ISBN 978-3-87429-425-6.
- Wu, Chung-Shien; Chaw, Shu-Miaw; Huang, Ya-Yi (2013). "Chloroplast Phylogenomics Indicates that Ginkgo biloba Is Sister to Cycads". Genome Biology and Evolution. 5 (1): 243–254. doi:10.1093/gbe/evt001. PMC 3595029. PMID 23315384.
- Kevan, P. G.; Bye, R. A. (1991). "The natural history, sociobiology, and ethnobiology of Eucheira socialis Westwood (Lepidoptera: Pieridae), a unique and little-known butterfly from Mexico". Entomologist. 110: 146–165.
- Designatable Units for Beluga Whales (Delphinapterus leucas) in Canada (PDF) (Report). Committee on the Status of Endangered Wildlife in Canada. 2016.
- Jefferson, Thomas A.; Webber, Marc A.; Pitman, Robert L. (2015). "Taxonomic Groupings Above the Species Level". Marine Mammals of the World. pp. 17–23. doi:10.1016/B978-0-12-409542-7.50003-2. ISBN 978-0-12-409542-7.
- Premo, L. S.; Hublin, J.-J. (6 January 2009). "Culture, population structure, and low genetic diversity in Pleistocene hominins". Proceedings of the National Academy of Sciences. 106 (1): 33–37. Bibcode:2009PNAS..106...33P. doi:10.1073/pnas.0809194105. PMC 2629215. PMID 19104042.
- COSEWIC assessment and update status report on the narwhal Monodon monoceros in Canada (PDF) (Report). Committee on the Status of Endangered Wildlife in Canada. 2004.
- Fraser, Thomas H. (14 August 2014). "A new genus of cardinalfish from tropical Australia and southern New Guinea (Percomorpha: Apogonidae)". Zootaxa. 3852 (2): 283–293. doi:10.11646/zootaxa.3852.2.7. PMID 25284398.
- "ITIS - Report: Panurus biarmicus".
- The dictionary definition of monotypic at Wiktionary