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Tuatara: Volume 17, Issue 3, December 1969

The Selection of Lectotypes In Palaeobotany

page 131

The Selection of Lectotypes In Palaeobotany

In the Past some workers in New Zealand palaeobotany did not designate holotypes or type specimens when describing new taxa (see Ettingshausen, 1891; Oliver, 1936). Thus lectotypes have to be designated by the first person to revise the work of these authors.

Holotypes

Under the rules of the International Code of Botanical Nomenclature, 1966 (hereafter called the ‘Code’), a holotype is ‘the one specimen or other element used by the author or designated by him as the nomenclatural type’ (Article 7, Note 2). Note 3 of the same article says that ‘if no holotype was indicated by the author who described a taxon … a lectotype … as a substitute may be designated’. Arber (1917) designated a single ‘type specimen’ for each new species he described. As this constitutes a definite elevation of one specimen of a series above the others, Arber's ‘type specimens’ are holotypes. The specimens associated with a holotype in a syntypic series may be called paratypes.

Lectotypes

The Code states that a lectotype must be selected from the original material, taking into full account the original description and illustrations. It is recommended that the lectotype be selected from figured syntypes, which are those specimens mentioned by an author when no holotype was chosen (Article 7, Note 3).

In a revision of the systematics of the New Zealand fossil flora a type specimen for each species must be chosen from the material described by Ettingshausen (1891) and Oliver (1936). These type specimens will be either holotypes or lectotypes. There are three cases:

1.

When only one specimen was found, validly described and illustrated as new species, this specimen becomes the holotype whether or not the original author designated it as such (Code, p. 71, para. 1). Knightia oblonga Oliver (1936) was represented by only one specimen and this becomes the holotype.

page 132
2.
When a single specimen of a series was validly described and illustrated as a new species, this specimen may be either:
(a)

a holotype, if designated as such or as ‘the type’ by the original author or,

(b)

a lectotype, if it was not designated as the holotype or as ‘the type’ by the original author.

Two specimens of Ulmophyllon pliocenicum Oliver (1936) were found; one was illustrated. This specimen becomes the lectotype. The associated specimen remains a syntype.
3.

When two or more figured specimens of a series are validly described and illustrated as a new species, these specimens are syntypes. A lectotype may be chosen from the original illustrated specimens, taking the original description into full account. All specimens associated with the lectotype remain syntypes. Numerous leaf impressions of Fagus maorica Oliver (1936) were found; two specimens were illustrated. These are syntypes until a lectotype is chosen from them.

The meaning of Article 7, Note 6 of the Code is not entirely clear. It states that ‘the type of the name of a taxon of fossil plants of the rank of species or below is the specimen whose figure accompanies or is cited in the valid publication of the name. If figures of more than one specimen were given or cited when the name was validly published, one of these specimens must be chosen as type’. The word ‘type’ must in this context mean lectotype. Under this provision the choice of lectotypes is restricted to figured specimens even if there are better unfigured syntypes.

The designation of the lectotype should be made by a competent palaeobotanist because ‘the author who first designates a lectotype … must be followed’ (Article 8). If an author feels unable to designate a holotype or lectotype all specimens must be called syntypes.

References

Arber, E. A. N. 1917: ‘The Earlier Mesozoic Floras of New Zealand’. N.Z. Geol. Surv. palaeont. Bull. 6.

Ettingshausen, C. von 1891: ‘Contributions to the knowledge of the fossil flora of New Zealand’. Trans. N.Z. Inst. 31: 557-64.

International Code of Botanical Nomenclature, 1961, Utrecht, Netherlands.

Oliver, W. R. B. 1936: ‘The Tertiary Flora of the Kaikorai Valley, Otago, New Zealand’. Trans. Roy. Soc. N.Z. 66(3): 284-304.

* Present address: New Zealand Geological Survey, Department of Scientific and Industrial Research, Lower Hutt, New Zealand.