Nominal taxon

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In zoological nomenclature, a taxon is called a nominotypical taxon , also (formerly) nominate form , which is defined by the same name-bearing type as the higher-ranking taxon to which it belongs.

In biology, newly discovered "forms" ( taxa ), such as a species , are described and named using a so-called type specimen . The great tit was scientifically described by Carl von Linné in 1758 under the name Parus major . After this species was divided into several subspecies by other biologists, Linnaeus' description and the name-bearing type specimen now define not only the species Parus major , but also the subspecies Parus major major . Therefore this subspecies is the nominate form of the species Parus major .

According to the International Rules for Zoological Nomenclature , however, the term nominotypic taxon is used today. This concept only applies to the priority groups family , genus and species .


The name of a taxon (a subspecies, species, genus or family) is linked in the rules for naming (nomenclature) to an actually existing specimen (or several), the so-called type . The purpose of this rule is to clearly define the bearer of the name - even in the event that the taxon is later redefined, divided or merged with another. If, for example, a species is split into two species based on newly recognized characteristics, a decision is made based on the type as to which of these species will keep the original name. The other species, previously considered to be part of the same species, is then given a new name. Taxa that follow in rank above the species (such as genera and families or ranks derived from them) do not receive their own type, but are assigned the type of a species. When describing a new genus, a type species must always be specified, analogously for families. The type of this species thus also becomes the type of the genus or the family. This regulation ensures that, in the case of taxonomic regroupings, the name can never move completely away from the original group on which the first description was based - no matter how often and how deeply it is regrouped later.

In the event that a taxon is later split up, for example a family into subfamilies, the nomenclature code regulates that the subfamily that contains the type for the family also receives the same name as the family (of course with an adapted ending). This subfamily with the named type becomes the "nominotypical" taxon.

If, for example, the family “Tipulidae” is split into subfamilies, one of the subfamilies is always given the name “Tipulinae” - namely that which contains the type genus Tipula . The type species in this case is Tipula oleracea Linnaeus, 1758, the (neo-) type of which is in the Museum Alexander Koenig in Bonn. The subfamily to which the museum specimen kept in Bonn belongs must therefore be called “Tipulinae”, regardless of how it is otherwise circumscribed and delimited. Analogous regulations apply to sub-genera and subspecies. In the case of subspecies, this means that there must always be at least one nominotypical subspecies ("nominate form"). This is not the most common or “typical”, but the one that contains the type specimen of the species.


Subfamily Homininae in the Hominidae family

All genera of the so-called great apes (including the genus orangutans ) together make up the family of Hominidae . This taxon is based on "man"; H. of the genus Homo as a typical taxon of this family. In the terminology of the zoological nomenclature code , the genus Homo as a type genus thus forms the name-bearing type of the family Hominidae. The genus Homo, in turn, is defined by the type species Homo sapiens as a name-bearing type.

Now it can happen that in order to better illustrate the systematic relationships in the nomenclature within a ranking group, further taxa of lower or higher ranks are introduced, e.g. B. a new subfamily. One such subfamily are the homininae , in which humans, chimpanzees and gorillas (along with all their fossil ancestors) are grouped together; however, the more distantly related orangutans are not among them. The subfamily Homininae is also defined by the genus Homo as a name-bearing type. Taxa of such ranks, which are defined on the same named type of a taxon of a higher rank, but within the same rank group, are called nominotypic taxa.

Nominotypical taxa within the species group

In 1855, Gray introduced the magnificent terrapin Rhinoclemmys pulcherrima under the original name combination Emys pulcherrimus . A large number of Rhinoclemmys pulcherrima subspecies have now been established. Consequently, the subspecies Rhinoclemmys pulcherrima pulcherrima (Gray, 1855) exists as a nominotypical taxon for the species Rhinoclemmys pulcherrima (Gray, 1855). Both taxa are based on the same named type, in this case a specific type specimen. All other pulcherrima subspecies are based on their own specific type specimen as a name-bearing type.

Nominotypical taxa within the genus group

Here nomenclatory actions on taxa of the generic group within the trilobite family Phacopidae Hawle & Corda, 1847, are explained:

In 1972 Wolfgang Struve introduced a new sub-genus under the title Phacops (Pedinopariops) n. Sg. a. The name-bearing type is the species Phacops (Phacops) lentigifer Struve, 1970. Struve later raised Pedinopariops to the rank of a genus and introduces Struve, 1982 as a subgenus Pedinopariops (Hypsipariops) . According to these nomenclature actions, a nomenclature results with the genus Pedinopariops Struve, 1972 and its nominotypical taxon Pedinopariops (Pedinopariops) Struve, 1972. Both are based on the species Phacops (Phacops ) lentigifer Struve, 1970 as the named type. Another sub-genus of the genus Pedinopariops is Pedinopariops (Hypsipariops) Struve, 1982 with the species Pedinopariops (Hypsipariops) lyncops Struve, 1982 as the name-bearing type.

Nominotypical taxa within the family group

The detailed but complex example shows the principle of coordination in conjunction with the priority principle :

The Belgian Echinodermologe Georges Ubaghs leads 1953 with the superfamily "Melocriniticea Ubaghs nov." A new nominal crinoids taxon with the families Melocrinitidae Zittel , 1878 and Scyphocrinitidae Jaekel , 1918. Due to the rules of nomenclature, Ubaghs later interpreted and corrected this nomenclature act as follows: The family Melocrinitidae Zittel, 1878 becomes synonymous with the family Melocrinitidae d'Orbigny , 1852 (pro Melocrinidae d'Orbigny 1852). Due to the principle of priority, the family Melocrinitidae d'Orbigny, 1852 becomes the valid name. In accordance with the principle of coordination, a superfamily Melocrinitacea, introduced as a latent by d'Orbigny in 1852, becomes available at the same time. This taxon becomes valid as an older synonym for Melocriniticea Ubaghs, 1958. According to the nomenclature actions presented here, the valid nomenclature is the superfamily Melocrinitacea d'Orbigny, 1852 with the family Melocrinitidae d'Orbigny, 1852 as a nominotypical taxon. Both are based on the genus Melocrinites Goldfuß , 1824 as the name-bearing type. Within the superfamily there is the further family Scyphocrinitidae Jaekel, 1918 with the genus Scyphocrintes Zenker, 1833 as the name-bearing type.

Use in botany

In botany , the term nominotypical taxon is also used by some scientists, even if it does not appear in the code of botanical nomenclature . Instead, the term autonym has been used there since 1972 .


  • Gerhard Becker (2001): Compendium of Zoological Nomenclature. Terms and symbols explained by German official texts. Senckenbergiana lethaea, 81 (1): 3-16; Frankfurt am Main.
  • International rules for zoological nomenclature . Adopted by the International Union of Biological Sciences. Official German text . In: Otto Kraus (Ed.), International Commission on Zoological Nomenclature (Ed.): Treatises of the Natural Science Association in Hamburg (NF) 34 . 4th edition.

Individual evidence

  1. IRZN 2000: p. 168
  2. Code Article 61. Principle of Typification.
  3. Code Article 37. Nominotypical taxa.
  4. Code Article 44. Nominotypical taxa.
  5. Code Article 47. Nominotypical taxa.
  6. Name-bearing type: “The type genus, type species, the holotype, lectotype, the series of syntypes (these are generally considered to be the name-bearing type) or the neotype; they all guarantee the objective reference basis on the basis of which the use of a name for a nominal taxon can be determined. ”IRZN 2000: 169 [Glossary].
  7. ^ W. Struve (1972): Phacops species from the Rhenish Devonian. 2. Sub-class assignment. Senckenbergiana lethaea, 53 (2): 395; Frankfurt am Main.
  8. W. Struve (1982): New studies on Geesops (Phacopinae; Lower and Middle Devonian). Senckenbergiana lethaea, 63 (5/6): 488; Frankfurt am Main
  9. G. Ubaghs (1953): Classe des Crinoides . In: J. Piveteau [Ed.], Traité de Paléontologie , 3: pp. 741-742; Paris.
  10. G. Ubaghs (1978): Camerata . In: RC Moore [Ed.], Treatise on Invertebrate Paleontology , Part T (Echinodermata 2), Volume 2: T491-T492; Lawrence / Kansas.
  11. ^ Gerhard Wagenitz: Dictionary of Botany. Morphology, anatomy, taxonomy, evolution. 2nd, expanded edition. Nikol, Hamburg 2008, ISBN 978-3-937872-94-0 .

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