[Taxacom] sufficient evidence for new species

Fri Jan 25 02:12:34 CST 2019

Hi!

I am a botanist, so I possibly face more problems with hybrids and genetically abarrant individuals than zoologists generally do, but my view on this, both personally and as editor of a major journal in the field, is that presumed taxa only known from a single individual should better not be described and named. At least as long as the single individual known has not been kept in cultivation, observed for a long time and been genetically investigated, the risk is far too large that a single individual with unusual morphology is a unicum, possibly a hybrid or genetically defect individual, rather than a member of stable population of a species.

Furthermore, I use to argue that since it is impossible to know anything about the range of variability of a taxon only known from a single specimen it is simply not possible to provide a morphological description of it that is useful. In my own research, I continiously have to struggle with taxa described from very scanty material and I have several cases with species that I feel I have to treat as if they have never been refound/recollected although there are modern collections of specimens that may possibly belong to these species but which are not identical in all respects with the original diagnose and type material and which I does not dare to identify as members of the old species (in particular not since that would have large implications for various conservation measures.

However, if you are publishing a revision/treatment of the relevant species, it may still of course be a good idea to briefly mention and describe whatever deviating specimens you may have, just to make people aware of their existance if or when similar specemens are recollected in the future.

Yours,
Torbjörn

25 jan. 2019 kl. 08:30 skrev Donat Agosti <agosti at amnh.org<mailto:agosti at amnh.org>>:

Hi John
This analysis https://doi.org/10.3897/rio.3.e12502 of how many specimens are cited in taxonomic  treatments in a sample of recent publications indicates that you would not be the only scientist describing species based on a single (holotype) specimen.

"About a third of treatments (72 of all species treatments, 34 of new species descriptions) were based on a single specimen" .

The relatively high number of treatments with only one specimen cited is not just an artifact. In fact, a raw analysis of 8.716  treatments of new species including a holotype in TreatmetBank shows that 26% of descriptions of new species are based only on one specimen, and 90% of such treatments include 9 or less specimens.

Donat

-----Original Message-----
From: Taxacom <taxacom-bounces at mailman.nhm.ku.edu<mailto:taxacom-bounces at mailman.nhm.ku.edu>> On Behalf Of John Grehan
Sent: Thursday, January 24, 2019 6:26 PM
To: taxacom <taxacom at mailman.nhm.ku.edu<mailto:taxacom at mailman.nhm.ku.edu>>
Subject: [Taxacom] sufficient evidence for new species

Dear colleagues,

I would be interested in any feedback opinion on what I admit might be taxonomic heresy but I am in a bit of a dilemma. I have a situation where I have single specimens of moths of the same genus, each from different islands (Indonesian Lesser Sunda). In some cases I have genitalic differences so there is no problem recognizing different species for each island. But in two cases the abdomen had decayed (due to tropical field conditions presumably) that the genitalia were not preserved. However, in the other species I have also noted differences in the mouthparts. If for the two decayed specimens their mouthparts (labial palps) were intact and showed distinct differences, is there any major problem my describing these as new species based on that difference? It seems to me that it would be just as valid as genitalia or even any other consistent different, although not usual practice.

These moths are extremely rarely caught (at light, although likely actually present in high numbers) and it has taken years to obtain the single specimens. Of course I could just wait until more specimens turn up, but then I am getting on in years and don't want to chance missing the opportunity. There is no overriding rule about this but I would be interested in reactions (even to anticipate what I might have to confront in due course). Many thanks. John Grehan _______________________________________________
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Nurturing nuance while assaulting ambiguity for 32 some years, 1987-2019.
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Nurturing nuance while assaulting ambiguity for 32 some years, 1987-2019.

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Torbjörn Tyler, Ph.D,

– Curator at herbarium LD.
– Editor in Chief of Nordic Journal of Botany.

– Responsible for the project The Hieracia of Sweden.

Postal address:
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Private address: Enningervägen 12, SE-243 31 Höör (=Hoeoer), Sweden
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