I have opinions (expressed previously) about whether or not “taxon concept” is a well-defined and useful entity for thinking about nomenclature & taxonomy. However, in refining my thoughts on the topic, I arrive at a more basic question:
What resources should be used to understand the term “taxon concept” as used in iNaturalist? Are there published works or online resources that serve to thoroughly explain and nail down what this term means and how it should be used?
Since the concept of species has evolved over time and there are different views on that which keep taxonomic debates going, I think the more general taxon concept (which presumably includes any and all taxa, from domain to subspecies and varieties) would be even harder to pin down.
If I’m understanding what you’re trying to get at … iNat leaves off the name of the original describer and year described for all scientific names. I assume this was intentional, maybe deemed unnecessary for iNat users. My understanding is that if you want to know why (and how) a particular scientific name is being used on iNat you have to go to the source (the taxonomic reference[s] being used for any given organismal group) and then perhaps the primary literature which was used by that reference. iNat is not itself a taxonomic reference, merely a user of taxonomy.
As used in an iNaturalist context, and most other biodiversity informatics contexts so far as I know, a taxon concept isn’t an answer to “what is a taxon?” in the way a species concept is an answer to “what is a species?” Rather, it’s intended to differentiate between different taxonomists referring to differently circumscribed taxa by the same name.
For instance, suppose I recognize Cylindropuntia imbricata and Cylindropuntia spinosior as two separate species, while you consider Cylindropuntia spinosior to be a synonym of Cylindropuntia imbricata. We mean different things by the name “Cylindropuntia imbricata”; my taxon concept for Cylindropuntia imbricata is different than yours. The question, then, is how we deal with this in the data… e.g., how do we unambiguously refer to one taxon concept rather than the other, how different do two circumscriptions of a taxon have to be for us to consider them separate taxon concepts, how do we differentiate misidentifications from use of different taxon concepts, and so on. Not necessarily easier problems, but at least different problems than those surrounding species concepts.
That’s a different issue… e.g., in the example of Cylindropuntia imbricata, the different taxon concepts wouldn’t be reflected in any difference in the authorship of the name.
In principle, the way it’s supposed to work in iNaturalist is that we reference an external authority and everyone uses the taxon concept from that authority. For instance, the iNaturalist entry for Cylindropuntia imbricata might specify that the name is being used for the same taxon concept as the entry for that name in Plants of the World Online. Then those of us identifying plants by that name in iNaturalist would first go check POWO to figure out what the taxon concept is there, and we’d apply the same taxon concept while using iNaturalist. Further, when iNaturalist has multiple entries for the same name but with different taxon ID numbers (almost always, only one of these being “active”), theoretically these ought to represent different taxon concepts. At least, I think that’s how it’s supposed to work. None of this is very well documented, though.
In practice, there are several problems. In terms of mere logistics, I think it’s rare for identifiers on iNaturalist to check whatever external authority is referenced—most IDs on the platform, including most of mine for that matter, are probably being made by people who don’t really have any idea whether or not their concept of a given taxon matches that given by iNaturalist’s external authority. That’s a big problem, but not a conceptually interesting one. :-) The conceptually interesting problem is: Well, what does it mean for me to be using the same taxon concept as POWO in the first place, and how would I or anyone else know whether or not I’m using the same taxon concept? In some cases this is pretty straightforward, but there’s a vast and poorly understood landscape of ambiguous cases.
I’ll grant you it’s imperfect and can be messy. I see iNat still lumps all the Peromyscus maniculatus together and references the Am. Soc. Mammalogists Database, but that database has already split out the western North American populations of Pm into two other species. If I post a record to iNat from New Mexico I have to use P. maniculatus (sensu lato) because that’s the taxon concept still in use there even if that species, in the most current (and narrow) sense, doesn’t occur in the state. Will probably get aligned at some point. Not an ideal situation but I can live with it. .
Given that we are living with it, I think it’s worth understanding what the iNaturalist “taxon concept”-based system (and similar systems implemented elsewhere, for that matter) is actually intended to accomplish and whether or not it does so. :-)
At present, I have opinions on both points, but obviously the best way to know what it’s intended to accomplish is to hear it from the people who intended it to accomplish something—and that I have not yet done. :-)
There’s disagreement among taxonomists, too, on various points. I don’t think I’ve encountered the term “chresonym” before; on googling it, I’m familiar with the concept, but not with a term with that specific meaning.
I’d agree that moving a name from one genus to another does not of itself change the taxon concept, though, and I don’t think there’s anything in iNaturalist that corresponds clearly with either nomenclatural or taxonomic synonymy.
This indicates one of the basic issues I’m curious about. The idea, as I understand it, is that iNaturalist can provide clear and lasting documentation of the taxon concept used here by reference to an external authority. But, of course, anything that is not defunct is updated—we’re pointing at a moving target, not a fixed landmark.
I would add that we cannot practically know that without spending excessive amounts of time researching it. Say you have a standard panel of 30 observations in the “Identify” tab. Are you going to spend one minute researching what taxon concept iNaturalist is using for each of them, for a total of 30 minutes? Would doing so really improve the quality of data enough to be worthwhile?
Agreed. It’s a problem in the “it prevents taxon concepts from accomplishing what I think they’re supposed to accomplish” sense. I’m not convinced that means it’s a problem in the “thing we ought to change” sense, though.
In a nutshell, the concept of a taxon are its boundaries as stated sometimes in its original description, and more often in the current, commonly accepted revision, provided such an object exists.
I have found this paper very useful: https://www.researchgate.net/publication/228951937 : Franz N, Peet R, Weakley A. 2008. On the use of taxonomic concepts in support of biodiversity research and taxonomy, pp. 63–86 In Wheeler QD [ed.], The new taxonomy. Taylor & Francis, Boca Raton, FL.
As someone who is just stumbling upon this post… what IS a taxon concept? Never heard this term before and searching it up just seems to give me a lot of threads of people nit-picking the definition but I still can’t grasp what it means. Anyone want to explain it in baby terms or maybe with an example for me?
An example. If you ask “what is the name of the beetle in this observation https://www.inaturalist.org/observations/109444985 ?” I will answer: According to the current taxon concept, it is Charopus rotundatus Erichson, 1840: a beetle with a wide Western Mediterranean distribution. However, I have recently published a paper that (I hope) demonstrates that in the last 150 years previous Authors did not look close enough to these small fellows, and the Iberian specimens are different enough to be considered a valid species, whose proper name should be C. multicaudis Kiesenwetter, 1866. IF my views are accepted, the taxon concept for C. rotundatus will eventually become much narrower than today. For the moment, in iNat there is just a flag on the species. Better not go at a fast pace on these subjects.