Taxacom: When to designate lectotypes

[Adam Cotton]

There is no issue with designating a lectotype because there is a 
specific need for one when working on a single taxon or a small group of 
taxa, particularly if there is a nomenclatural issue involved that can 
easily be solved by lectotype designation. The important point here is 
that lectotype designation should be justified, rather than purely to 
put a label on one specimen 'for the sake of it'. If all syntypes are 
definitely the same taxon then in reality there is no good reason to 
designate one of them as the lectotype, even in a revision of the group 
to which the taxon belongs.

John asked:
> Can a single syntype be referred to as a holotype even though no individual specimen was designated in the publication?
I would say the answer to this should usually be 'no', unless it is 
absolutely obvious from the original description that the author only 
saw a single specimen.

In the case that John brought up Rothschild could have seen more than 
one specimen, even though there is currently only a single extant 
specimen in the Rothschild Collection (NHM, London). This should be 
treated as a syntype rather than 'the holotype'. If in future other 
specimens are identified as syntypes then it MAY be necessary to 
designate the Rothschild specimen as lectotype. In the case that there 
is only a single known syntype it is not necessary to designate it as 
the lectotype.

It should also be noted that round red 'type' or 'holotype' labels were 
affixed to many specimens in the NHM Collection during and after WWII, 
but this does not indicate that the specimens are valid holotypes. Their 
status depends on the original description which needs checking in each 
case. Also some NHM specimens labelled in this way are actually 
demonstrably not type specimens at all, particularly in the 'Main 
Collection'. This is usually because in the rush to evacuate type 
specimens from London in 1939 for safety, sometimes the wrong specimens 
were chosen and labelled as types.

Adam.


On 21/02/2025 00:24, John Grehan via Taxacom wrote:
> As one who easily gets lost in the nomenclatural forest (of course my fault
> for not taking this on in detail, but started quite late in life with
> taxonomy and now at my age, with limited time left and too many other fish
> to fry, I tend to lean on the insights and knowledge of others [in
> appreciation] who have made nomenclature a central focus), this feedback is
> quite helpful, although not sure if I have perceived everything accurately.
> But for now, it seems that a primary theme is that "The designation of
> lectotypes should be done as part of a revisionary and other taxonomic work
> to enhance the stability of nomenclature, and not for mere curatorial
> convenience." Also, where there is a single syntype, it should not be
> designated a lectotype (presumably it remains designated as a syntype - by
> 'syn' implies shared and a single specimen is no 'shared' is it? Can a
> single syntype be referred to as a holotype even though no individual
> specimen was designated in the publication?
>
> The restriction of designating lectotypes only as part of a revisionary
> work is problematic. In the world catalog of Hepialidae we designated
> several lectotypes in order to "enhance the stability of nomenclature".The
> alternative to not to do so would have retained ambiguity and uncertainty
> in these cases.
>
> Cheers, John