About the concept of species, use of locations for ID, and related expectations on ID accuracy

Starting this new thread as this is a side theme emerged in the Etiquette for ID of species with no visual differences .
I had read some posts there (for instance
@charlie https://forum.inaturalist.org/t/etiquette-for-id-of-species-with-no-visual-differences/9513/16
@melodi_96 with https://forum.inaturalist.org/t/etiquette-for-id-of-species-with-no-visual-differences/9513/22

which came to my mind this morning while discussing (elsewhere, with a lady with degree in Natural Sciences) the topic of species identification using barcoding etc.
What I have been explained is that the topic of definition of a genus is a tricky topic often brought up at the biogeography (sorry from now on for the lingo, I know the italian terms, not sure what are the proper ones in English) exams in the Natural Science curricula.

in particular the old concept of species where the tell-apart factor is sterile hybridization is not considered that valid (or at least universal criteria) and currently there has been a move towards a concept of genetic distance and biogeographycal distance.

Examples brought are

  • Emys trinacriae been distinguished as a new species from E. orbicularis based on their different location. Not on the fact that they cannot interbreed with fertile offsprings if mixed
  • in botany, it seems it has never worked (my interlocutor told her professor of geobotany used to joke that “oaks are prostitutes”
  • micro-organism where reproduction is not sexual.

reference given is a book by Zunini-Zullini " Biogeografia. La dimensione spaziale dell’evoluzione"

Now, I thought worth discussing as there seem to be some animus in using the location as a way to determine species which at this point should not (always) be.
And I think this should also reframe the expectations when striving for the absolute precision using macrophotography to proceed with an ID. 100% certainty in most cases cannot be reached, if what I have been told is correct. And expectations on iNat ID should go along.

Your opinion?
Writing this post to get also some further elaboration from people working with Natural Science. This does not mean I do not welcome other contributions, too.

Please note! I’d like the contributions to be humble and polite, without people throwing adjectives around from their high horses. Saying just to avoid what happened in the other thread. Thanks!


2 comments - the use of location as a factor to separate species, especially at a smaller level of geography is a path toward circular reasoning. ‘This what is supposed to be here, therefore this must be that’ is not evidence that is what it is.

I still hold to what I have written elsewhere that ID’s should be based on the morphological evidence provided, and no more precise than that.

‘Location’ is a very loose term to use - are we talking geographic location, are we talking habitat, elevation etc.

I do have a few concerns about this comment, why should the discussion be limited to people only working in the natural sciences ? Does the fact that my background is in biostatistics invalidate my comments ? If so, then I will remove my post.


no didn’t mean that of course (that’s what the also was there for!). I just hoped to get some more insight on the current view at academic level. Didn’t write “academics contribution welcomed only”. In fact, I asked for opinions. Sorry if that was misunderstood, I’ll see how to rephrase that.


Location data can be and often is used to make a decision about a species when other evidence is ambiguous. Not just on iNat but in research museums and by biologists in the field who might have the organism in hand but still can’t reliably separate it based on physical characteristics from a similar species that occurs elsewhere. It’s not a perfect way to do species IDs and, yes, it relies on assumptions about where species occur and don’t occur. But nothing is perfect.


I am curious why this thread was created when there are already other duplicate threads including recently active ones. Would you all be OK with me merging it into one of those?

of course, could not find them using the search function, but if the topic is the same I’m perfectly fine.

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No. Your point is valid for my amateur observations as well. I have calcareous fen observations that are a special habitat for species distribution well outside the norm. (Strange but true) The plants in question were Id’d off the checklist with the sate biologist present in the field. But the iNat scientific community did not accept the location of the observation and therefore have overruled my ID. I will go do my book work and deal with that myself. The point is that the ID provided in the field by the state Biologist was rejected solely based on distribution.


Did you explain the situation on the observation? I’m not sure what you mean by “did not accept the location of the observation”, but I think nearly all iNat users will be very willing to discuss, explain, and possibly retract their identifications if you engage with them.

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Sorry for that… I am waiting to run into a similar situation for a high ground Ranunculacea I am waiting to flower in my low hills.
In these cases I just explain the situation and opt out of Community ID if people do not listen.
Or, atomic option I have used a couple of times, duplicate and delete to restart afresh when people just do not care or disappear after dropping crazy IDs on obs of uncommon and complicated specimens. Don’t give up!
Of course I am not saying that location should be the only criteria! Just talking in case there is no other reason to believe the ID is different. In your case I would have explained what were the characters used by the biologist for the determination. It would have been a very interesting observation for anyone :slightly_smiling_face:

For species whose distributions are well known, well understood, well documented AND that are very unlikely to disperse outside their documented range, then ID by location is fine. But that rules out lots of species! Geomys (pocket gophers) are an exception–they can ONLY be identified by location (or DNA sequence). Most species have very well documented ranges and there’s no possibility for dispersal. I’ve created very detailed and accurate taxon ranges for the purpose of allowing accurate IDs based on the range maps alone (since it’s usually just the mound that is observed and even if you had one in hand it wouldn’t matter as they all look the same. See here: https://www.inaturalist.org/journal/pfau_tarleton/29122

About the concept of species itself–well, scientists have been debating that for 200 years with no sign of a concensus yet.


You are right. It can be very difficult to express a complex story in short form writing. I certainly meant no disparagement to any one. I would like to take a step back and say the onus is on me to work the extraordinary observation through to the end.
Even my final point did not come across as intended. Wow.

I am saying, the extraordinary finding should be weighted by location and location should be used to require extraordinary proof.

Yes, I can see that what I was thinking was not at all what I said. I hope this helps.


I often have people email me fuzzy photos of some animal they saw and would like IDed. More often than not,my first question to them is “Where did you find it?”. It’s remarkable how often that info is not provided up front, as though it’s unimportant. If I know where the pic was taken, it often excludes many other similar species and I can narrow down the possibilities rather quickly. The example by @pfau_tarleton of pocket gophers is a very good one.

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the more I read, the more I believe we should tune down expectations of species identification based on visual aspect. Probably only barcoding is a safe reference.
This is not meant to embrace nihilism, but the animus on species ID and precision I feel is a bit misplaced, also on a scentific point of view

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