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, as the only extant species is Ginkgo biloba.
- 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 dugong is the only extant taxon in its entire family.
- Homo Sapiens (humans) are the only extant species in their genus along with too little genetic diversity to harbor any living sub-species.
- monodon monoceros, also known as the narwal is a medium sized cetacean that shares a family with belugas, but are the only extant member of its genus.
- The ornithorhynchus anatinus is the only extant member in the ornithorhynchidae family in contrast with tachyglossidae with four species.
- The aardvark (Orycteropus afer) is the only species in the order Tubulidentata.
- Ozichthys albimaculosus, the cream-spotted cardinalfish, found in tropical Australia and southern New Guinea, is the type species of the monotypic genus Ozichthys.
- Panurus biarmicus, the bearded reedling, has a three subspecies across its range, but belongs to the genus Panurus, which current knowledge considers monotypic (the only genus) within the family Panuridae.
- Ursus maritimus, the polar bear, despite being only one of six extant members of the Ursus genus, is still left with no living subspecies.
- 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.
- "Are humans Monotypic?". philosophy-question.com. Retrieved 2022-01-17.
- 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.
- "Ornithorhynchidae (Platypus)".
- Schlitter 2005, p. 86 harvnb error: no target: CITEREFSchlitter2005 (help)
- 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".
- Rice, Dale W. (1998). Marine Mammals of the World: Systematics and Distribution. Special Publications of the Society for Marine Mammals. Vol. 4. Lawrence, Kansas: The Society for Marine Mammalogy. ISBN 978-1-891276-03-3.
- The dictionary definition of monotypic at Wiktionary