Chapter 16: Types in the Species Group

Article 75. Neotypes.

75.1. Definition. A neotype is the name-bearing type of a nominal species-group taxon designated under conditions specified in this Article when no name-bearing type specimen (i.e. holotype, lectotype, syntype or prior neotype) is believed to be extant and an author considers that a name-bearing type is necessary to define the nominal taxon objectively. The continued existence of paratypes or paralectotypes does not in itself preclude the designation of a neotype.

75.2. Circumstances excluded. A neotype is not to be designated as an end in itself, or as a matter of curatorial routine, and any such neotype designation is invalid.

Example. If an author designates a neotype for Xus albus Smith, a species about whose identity there is no doubt and which is not involved in any complex zoological problem at the time at which it was designated, the purported "neotype" has no name-bearing status.

75.3. Qualifying conditions. A neotype is validly designated when there is an exceptional need and only when that need is stated expressly and when the designation is published with the following particulars:

75.4. Priority. The first neotype designation published for a nominal species-group taxon in accordance with the provisions of this Article is valid and no subsequent designation, except one made by the Commission under the plenary power [Art. 78.1], has any validity (also see Article 75.8 for the status of a neotype if a former name-bearing type is rediscovered).

Recommendation 75A. Choice of neotypes. Authors are advised to choose neotypes from any surviving paratypes or paralectotypes unless there are compelling reasons to the contrary, such as data inadequate to meet taxonomic requirements, the poor condition of the specimens, or probable mixture of taxa. All things being equal, topotypic specimens (see Glossary) from the type series should be given preference.

Recommendation 75B. Consultation with specialists. Before designating a neotype, an author should be satisfied that the proposed designation does not arouse serious objection from other specialists in the group in question.

75.5. Replacement of unidentifiable name-bearing type by a neotype. When an author considers that the taxonomic identity of a nominal species-group taxon cannot be determined from its existing name-bearing type (i.e. its name is a nomen dubium), and stability or universality are threatened thereby, the author may request the Commission to set aside under its plenary power [Art. 81] the existing name-bearing type and designate a neotype.

Example. The holotype of the ammonite species Cycloceras laevigatum M'Coy, 1844 lacked important diagnostic features. Upon request the Commission under its plenary power set aside the type status of this specimen and designated a neotype (Opinion 1720 (1993)).

75.6. Conservation of prevailing usage by a neotype. When an author discovers that the existing name-bearing type of a nominal species-group taxon is not in taxonomic accord with the prevailing usage of names and stability or universality is threatened thereby, he or she should maintain prevailing usage [Art. 82] and request the Commission to set aside under its plenary power [Art. 81] the existing name-bearing type and designate a neotype.

Example. On discovering that the only existing type specimen of Aradus caucasicus Kolenati, 1857 (Heteroptera) was a specimen of another species, Kerzhner & Heiss (1993) proposed that the prevailing usage of the names of both species should be conserved by the designation of a neotype for A. caucasicus under the Commission's plenary power, and this was accepted in Opinion 1783 (1994).

75.7. Status of neotypes designated before 1961. A neotype designation published before 1961 takes effect from its date of publication if it then fulfilled all the provisions of this Article; it is invalid if it did not fulfil them.

Recommendation 75C. Invalid designations. An author who published an invalid neotype designation before 1961 should if possible be given an opportunity to make it valid before another author designates a neotype for the same nominal species-group taxon.

Recommendation 75D. Preference for earlier invalid "neotypes". If an invalid neotype designation was published before 1961, the specimen then designated should be given preference when a neotype for the same nominal species-group taxon is validly designated.

75.8. Status of rediscovered former name-bearing types. If, after the designation of a neotype, the name-bearing type (holotype, syntypes, lectotype or previous neotype) of the nominal species-group taxon that was (were) presumed lost is (are) found still to exist, on publication of that discovery the rediscovered material again becomes the name-bearing type and the neotype is set aside (unless, following an application, the Commission rules that the neotype is to be retained as the name-bearing type).

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FranciscoWelterSchultes   Art. 75.5, 75.6, 75.8


It has been suggested at the ICZN meeting at the IUBS Congress 14-16 Dec 2015 in Berlin to insert a provision of an epitype designation, also in course of a discussion to alingn Biocodes. In botany they made good experiences with epitypes.


However various arguments were brought forward that suggested it might be better to avoid it. A new term epitype would make the ICZN Code once again more complicate than necessary. Also the zoological community displays less harmony than the community of botanists. Zoological epitypes might much more easily become disputed, which would lastly increase workload for the Commission.


A better solution might be to work with neotypes instead of epitypes, and to insert a rule that adds a countdown time span (40 years seems to be an appropriate figure) that would have to elapse until a designated neotype would become the accepted name-bearing type of the taxon. Neotypes could be designated in all cases where taxonomists regard an existing type as unidentifiable (this would replace the epitype provision). If the designated neotype would not be disputed in any publication during this time span, it would effectively replace the existing name-bearing type after the countdown time passed.


Maybe combined with a rule that such a designated neotype must be announced in ZooBank, and perhaps also placed on an ICZN website so that every expert could look up quickly the currently pending neotype designations in their special taxonomic field of interest.


The publication containing the dispute would have to bring forward taxonomic reasons to justify the dispute (provision necessary to prevent abuse by blank disputes).

2015-12-18 18:46:38
FranciscoWelterSchultes   Recommendation 75A should be modified:

(...) All things being equal, topotypic specimens (see Glossary) from the type series should be given preference. When selecting a neotype, the author should, if possible, verify the accuracy of the locality ascribed to it. A neotype of accurately known locality should be preferred to one of inaccurrate or unknown origin.

This seems to be necessary, some authors seem to prefer historic specimens from vaguely known origins as neotypes for very local species, so an equivalent of Recommendation 74E (where the same was recommended for lectotypes) makes sense.
2009-03-31 08:16:15

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