Monotypic taxon

In biology, a monotypic taxon is a taxonomic group with only one biological type. The term's usage differs slightly between botany and zoology. The term monotypic has a separate use in conservation biology, monotypic habitat,^[1] regarding species habitat conversion eliminating biodiversity and restoration ecology concerning a dominant invasive biological type.

Botany

In botany, a monotypic taxon is a taxon that has only one species: Ginkgo is a monotypic genus, while Ginkgoaceae is a monotypic family. The phrase is not accurate in cases where a species includes more than a single type (specimen); some species may include several subspecies (or other infraspecific taxa) each of which will have a type. A more accurate term in those cases is unispecific.

• An example is the family Cephalotaceae, with only one species: Cephalotus follicularis, the Albany Pitcher Plant.

Zoology

In zoology, a monotypic taxon is a taxon that contains only one immediately subordinate taxon.^[2] For example, a monotypic genus has only one species. Conversely, one can say that the contained taxon is monotypic within the larger taxon; a genus monotypic within a family.

• An example is the genus Tarsius which is monotypic within the family Tarsiidae, which is itself monotypic in the Tarsiiformes. An example of a monotypic species is the Hyacinth Macaw (Anodorhynchus hyacinthinus), in which no subspecies can be distinguished. The Bearded Reedling (Panurus biarmicus) has a few subspecies across its range, but belongs to the genus Panurus (monotypic as to species), which current knowledge considers monotypic within the family Panuridae.

In the view of evolutionary biology, taxonomy is a means to represent phylogenetic knowledge. Thus the creating of monotypic taxa is avoided if it does not seem warranted e.g. is not supported by phylogenetic evidence such as fossils or inference from cladistic analyses.^[3]

Conservation biology and habitats

The monotypic habitat occurs in botanical and zoological contexts, and is a component of conservation biology. In restoration ecology of native plant communities or habitats, some invasive species create monotypic stands that replace and/or prevent other species, especially indigenous ones, from growing there. A dominant colonization can occur from retardant chemicals exuded, nutrient monopolization, or from lack of natural controls such as herbivores or climate, that keep them in balance with their native habitats. The yellow starthistle, Centaurea solstitialis, is a botanical monotypic-habitat example of this, currently dominating over 15,000,000 acres (61,000 km²) in California alone.^[4][5] The non-native freshwater zebra mussel, Dreissena polymorpha, that colonizes areas of the Great Lakes and the Mississippi River watershed, without its home-range predator control, is a zoological monotypic-habitat example.

See also

Biology portal

• Polytypic
• Race (classification of human beings) (a more detailed definition of monotypes in the context of humans, Homo sapiens)
• Conservation biology
• Category:Monotypic genera

Footnotes

References

• Mayr E, Ashlock PD. (1991): Principles of Systematic Zoology (2nd ed.). McGraw-Hill. ISBN 0-07-041144-1
• Parham, J.F. & Feldman, C.R. (2002): Generic revisions of emydine turtles. Turtle and Tortoise Newsletter 6: 28–30. PDF fulltext