[Taxacom] Retaining genus when its type species isn't diagnosable

Stephen Thorpe stephen_thorpe at yahoo.co.nz
Tue Dec 6 19:13:43 CST 2016

On the subject of "ongoing controversy" (relevant to the often overblown importance attributed to types), I have submitted the following correspondence to Zootaxa (no harm in giving people here a preview, and it may be modified somewhat after review): 

Is photography-based taxonomy really inadequate, unnecessary, and potentially harmful for biological sciences? A reply to Ceríaco et al. (2016).
Independent researcher, Auckland, New Zealand. E-mail: stephen_thorpe at yahoo.co.nz
An opinion piece was recently published in this journal which, remarkably, is less than one page in length, but has 493 authors (signatories) and has gained over 15 thousand reads on ResearchGate in a very short time. Ceríaco et al. (2016) argue for a blanket ban to be imposed on the uncommon practice of basing new species descriptions in zoology on photographic evidence only of the animal. I herein aim to show that their argument is a non sequitur, i.e. their stated reasons do not support their desired conclusion.
The arguments presented by Ceríaco et al. (2016) are vague, which makes it somewhat difficult to pin them down for the purposes of rebuttal. However, one line of argument involves the notions of material evidence, replicability and refutability. This is somehow linked to the idea that specimens have many characters not visible in photographs. They claim that the link between name and taxon is uncertain without the objectivity provided by a preserved type specimen, and that photo-based taxonomy will promote the flooding of the scientific literature with unverifiable and/or dubious taxa. They claim that it will also promote the idea that taxonomy can be done without dead specimens, leading to increased difficulties in obtaining collecting permits. Finally, they claim that photo-based taxonomy is unnecessary due to the fact that taxa can be referred to by informal names until preserved specimens can be secured.
Naming a new species is effectively to propose a hypothesis. That much is uncontroversial. However, the hypothesis is to be tested against subsequent material (specimens), not necessarily against the type specimen(s). This testing is an ongoing process. The type specimen is merely a nomenclatural entity to link a name with a species. That link may be uncertain for any number of reasons. There are various ways for routinely dealing with such uncertainty (including, for problematic cases, the designation of a neotype). These problems are the same whether we are dealing with preserved type specimens or type specimens known only via photographs. It is true that a photograph only has a limited subset visible of the full suite of characters, but the same is true of many preserved specimens. If you compare an ideal perfect preserved specimen with a photograph, then the former is indeed much better than the latter. However, the proper scientific approach is to make good use of whatever evidence one has got. Many new species hypotheses are based on imperfect specimens. It is impractical to require quality control checking of type specimens prior to publication of new species. A good photograph can, in some cases, be better than a poor specimen, so why impose a ban on the use of sufficient evidence, just because it is a photo? The fact that the use of poor photos can cause certain problems does not justify a ban on the practice, any more than the fact that the use of poor type specimens can cause (the very same) problems justifies a ban on specimen-based taxonomy. Specimens degrade over time and may even be inadequate initially (wrong sex or life stage, etc.) This leads to the same problems as for the use of poor photos. Ideally, we want a perfect type specimen to be preserved indefinitely, but sometimes a good photo may be sufficient for the purposes of naming a likely new species. Subsequent testing of that hypothesis will require careful analysis of specimens, but not necessarily the type specimens. Subsequently collected specimens are necessary for testing species hypothesis in any case.
Will the maintenance of the status quo, in which photo-based taxonomy is allowed, lead to a flood of unverifiable and/or dubious taxa? It is hard to understand why it would. It hasn’t so far. There may be a few unverifiable and/or dubious taxa in the literature, but these are mostly the result of problems with type specimens, not photographs. Anyone who proposed a new species based only on an inadequate photo would only be harming their own reputation, opening themselves up to ridicule. Therefore the idea of some coming flood of unverifiable and/or dubious taxa appears to be little more than an alarmist vision of the worst case scenario, with no real evidence in support of it.
Regarding the use of informal names, the whole point of formal scientific names is to provide a robust and rigorous system of naming, in order to avoid confusion. It is therefore very unclear why one would opt for a less robust or rigorous system of naming, thereby risking confusion? Informal names in the literature rapidly become confusing and hard to track. It can be very unclear if two informal names refer to two distinct taxa or the same taxon. This is precisely why we use formal scientific names.
I agree with Ceríaco et al. (2016) that there could be a problem with people misusing cases of photo-based description to lobby for tighter controls to be imposed on collecting. That would be very unfortunate and potentially damaging for the science of taxonomy. I do not dispute this risk, though I am unsure how likely it is to actually happen. Surely, the best approach would be to write papers advocating the importance of preserved specimens for taxonomy/systematics, rather than trying to impose a ban on something which may or may not add to the perceived risk?
Preserved specimens are absolutely necessary for the science of taxonomy, but they are not always necessary for the act of naming new species. There are just a few cases where it might be preferable to describe (name) a new species based only on photographic evidence. Nothing by Ceríaco et al. (2016) provides a compelling reason to impose a blanket ban on such a practice. Good taxonomy should be promoted whatever methodology is used. Photo-based taxonomy is never going to be useful for most taxa, but it may occasionally be useful for a few, so why impose a blanket ban on the practice?
Ceríaco, L.M.P., Gutiérrez, E.E., Dubois, A., et al. (2016) Photography-based taxonomy is inadequate, unnecessary, and potentially harmful for biological sciences. Zootaxa, 4196(3), 435-445. http://dx.doi.org/10.11646/zootaxa.4196.3.9

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