Chapter 16: Types in the Species Group

Article 74. Name-bearing types fixed subsequently from the type series (lectotypes from syntypes).

74.1. Designation of a lectotype. A lectotype may be designated from syntypes to become the unique bearer of the name of a nominal species-group taxon and the standard for its application (except in the case of hapantotypes [Art. 73.3]).

74.2. Lectotype found not to have been a syntype. If it is demonstrated that a specimen designated as a lectotype was not a syntype, it loses its status of lectotype.

74.3. Designation to be individual. Lectotypes must not be designated collectively by a general statement; each designation must be made specifically for one nominal taxon and must have as its object the definition of that taxon.

Example. Smith, revising collections described in publications by Dupont, made the statement that in the case of each new species described by Dupont "the specimen bearing the author's determination label is the type" or "the specimen listed first in the publication is designated as the lectotype". Such an act by Smith does not constitute valid lectotype designation.

74.4. Designation by means of an illustration or description. Designation of an illustration or description of a syntype as a lectotype is to be treated as designation of the specimen illustrated or described; the fact that the specimen no longer exists or cannot be traced does not of itself invalidate the designation.

74.5. Lectotype designations before 2000. In a lectotype designation made before 2000, either the term "lectotype", or an exact translation or equivalent expression (e.g. "the type"), must have been used or the author must have unambiguously selected a particular syntype to act as the unique name-bearing type of the taxon. When the original work reveals that the taxon had been based on more than one specimen, a subsequent use of the term "holotype" does not constitute a valid lectotype designation unless the author, when wrongly using that term, explicitly indicated that he or she was selecting from the type series that particular specimen to serve as the name-bearing type.

74.6. Fixation of lectotype by inference of "holotype" or "the type" before 2000. When it has been accepted that a nominal species-group taxon was based on a single specimen and the original description neither implies nor requires that there were syntypes, and if it is considered subsequently that the original description was based on more than one specimen, the first author to have published before 2000 the assumption that the species-group taxon was based upon a single type specimen is deemed to have designated that specimen as the lectotype.

Example. The fossil marsupial "lion" Thylacoleo carnifex Owen, 1858 was described briefly in the Encyclopaedia Britannica. The description included a figure of a cranium. Although the lower dentition was mentioned, there was no information that it did not form part of the same specimen. McCoy (1876) described a new nominal species Thylacoleo oweni, stating at the same time that the cranium described by Owen was "the first described type of the species" T. carnifex. The cranium has been accepted universally as the holotype. It is now known that the original description contained information partly based upon a portion of a mandible from a different locality. McCoy's (1876) inference that the cranium is "the type" is deemed to constitute lectotype fixation.

74.7. Lectotype designations after 1999. To be valid, a lectotype designation made after 1999 must

Recommendation 74A. Agreement with previous restriction. In designating a lectotype, in order to preserve stability of nomenclature an author should act consistently with, and in any event should give great weight to, previously accepted taxonomic restrictions of the application of the name.

Recommendation 74B. Preference for illustrated specimen. Other things being equal, an author who designates a lectotype should give preference to a syntype of which an illustration has been published.

Recommendation 74C. Data on the lectotype. An author who designates a lectotype should publish for it the data listed in Recommendation 73C, besides describing any individual characteristics by which it can be recognized.

Recommendation 74D. Choice between syntypes in several collections. When possible, a lectotype should be chosen from syntypes in the collection of a public institution, preferably of the institution containing the largest number of syntypes of the nominal species-group taxon, or containing the collection upon which the author of the nominal species-group taxon worked, or containing the majority of that author's types.

Recommendation 74E. Verification of locality. When selecting a lectotype, the author should, if possible, verify the accuracy of the locality ascribed to it. A syntype of known locality should be preferred to one of unknown origin.

Recommendation 74F. Paralectotypes. An author who designates a lectotype should clearly label other former syntypes as "paralectotypes". Like paratypes, paralectotypes have no name-bearing status, but they are eligible for designation of neotypes.

Preamble | Articles 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 | Glossary Appendices Constitution

FranciscoWelterSchultes   Art. 74.5 should contain an additional passage.

A lectotype is not to be designated for curatorial reasons alone, and any such lectotype designation is invalid.

This would be useful because the opportunity to designate lectotypes was abused by museum curators who designated lectotypes for curatorial purposes alone, simply because other museums also had lectotypes of the same taxon, to avoid that those could some day become name-bearing types, and that the own museum's types would loose name-bearing status.
I do not see a major problem to take this measure. Any subsequent researcher can select either the same or another lectotype, but it usually would make no difference to have a name-bearing lectotype or syntypes. In most cases the syntypes belonged to the same species.

2009-08-06 15:18:41
FranciscoWelterSchultes   74.7.3 should be modified.

It should contain the content of Amendment Declaration 44 (which practically means that the Article was replaced and that a statement of the taxonomic purpose is not required):

The wording of Article 74.7.3 is amended to read 'contain an express statement of deliberate designation (merely citing a specimen as "lectotype" is insufficient)'.

Example directly below Article 74.7.3:
'Example. A statement such as "lectotype hereby designated", "lectotype by present designation", "I choose specimen X as lectotype" would fulfil this requirement, but "lectotype: specimen X" would not'.

'Recommendation 74G. Not merely for curatorial purposes. The designation of lectotypes should be done as part of a revisionary or other taxonomic work to enhance the stability of nomenclature, and not for mere curatorial convenience'.

These amendments were backdated and apply to all works published after 1999.

Indirectly this means that the "express statement" in the definition of the term "designation" in the Glossary does not mean "express statement of deliberate designation".

I would prefer to have Recommendation 74G as an obligate rule and not only as a recommendation.

I would also consider it very helpful for taxonomic work if the requirement "express statement of deliberate designation" would also apply to lectotype designations from before 2000.
On the one hand this would make a great deal of previous lectotype designations invalid.
On the other hand stability would only be threatened if a taxonomist would deliberately designate as lectotype a specimen belonging to a different taxon than the previous questionable lectotype. This occurs extremely rarely.

It would be much easier for a revisor of a genus to expressly designate a commonly accepted but formally questionable lectotype as new, than to be forced to start a discussion on whether or not the lectotype was validly fixed under 74.6 or other conditions.

It is extremely difficult to make a difference between an incorrectly recorded "lectotype" specimen as a result from a misinterpretation of a previous questionable record, and a deliberately new lectotype designation.

Example: Zilch (1977) recorded types of collection material and mentioned "lectotype: specimen X" for taxon A and "lectotype (Pfeiffer 1956): specimen Y" for taxon B. Specimen Y was not validly designated as lectotype under the provisions of the 4th edition by Pfeiffer (1956), and Zilch's interpretation was incorrect. It is unclear what to do with specimen X in such a case.

Evenhuis (2007, Bishop Museum Occasional Papers 95: 20) argued that unintentional lectotype fixation should not be recognized if mentioning of lectotype specimens was based on previous records or acts which later result to be invalid (problem of "lectotypification by accident"). I agree with this view.
2009-03-16 10:38:25

Article74 (last edited 2009-04-27 12:42:13 by localhost)