ID Based on Range or Appearance

There’s a lot of disagreement in Louisiana/Mississippi about how to identify Lampropeltis holbrooki and L. nigra. There’s essentially two different viewpoints of identifiers: ID based on range (east or west of the Mississippi River) and ID based on appearance (whether or not an individual looks speckled or has few speckles with some dorsal cross bars). The most recent literature is fairly clear (from what I can tell) that range is about the only way to ID this species complex since the black kingsnake looks very similar to a speckled kingsnake in the southern part of its range. See this recent observation and this observation from last year for a quick look into the discussions between the two community viewpoints.

How should these species (and other similar species complexes) be identified for the sake of consistency across iNaturalist?

Irvin (ilouque)


range is a hard one. You have to consider it for a lot of things, like if i find a strange pine tree in Vermont, there are maybe 4 or 5 options, i can’t identify it if i literally consider every pine tree on the planet. But on the other hand, range IDs of closely linked and closely related species is super iffy because it creates a feedback loop. if the way you map a species is by being east of the Mississippi river, and you create data based on that premise, you then have data ‘supporting’ that range, and so forth. What my take is, which others may not agree on, is if they can’t be told apart by anything other than range, they should not be separate species in the first place, or barring that, there needs to be a species complex created and all of them need to be identified to the complex level, not the species level.

That being said i am a plant guy, not a herp guy, so i will leave it at that and see what others think.

edit: thanks Reuven, i totally forgot about the primary literature thing!


Official reference for iNat taxonomy is except for explicit discrepancies described here:

See also this (copied from

Most of our classifications come from our external name providers, but for some groups we try to adhere to different taxonomic authorities. Note that this means when we are tracking a secondary taxonomic authority like this, we explicitly do not track the taxonomy from the primary literature. We have a couple reasons for this:

  1. Taxonomy is subjective and not every scientist agrees with every paper While it may seem like the naming and classification of organisms is a formal process and all scientists agree on what names organisms should have, the truth is much messier. While there are standards for when and how an organism should be named, they do not apply to all taxa, and there are basically no universal standards for when two groups of organisms should be considered separate species. Biologists have never been able to agree on standards in these areas, so the result is much more akin to correct use of language than correct use of the periodic table: everyone has their own opinion, but most people tend to follow authorities (either individuals or groups) who they trust to make reasonable decisions about what names should be used. Thus, using names and classifications just because someone published a paper declaring that they should be used (even a peer-reviewed paper) is not a great idea, because it doesn’t prove that the scientific community supports that paper’s assertions.
  2. iNaturalist is not a place to argue about taxonomy Or at least we don’t want it to be. Since taxonomy is subjective, people argue about it all the time, and since there is no absolute truth one can apply to settle such disputes, they can become rancorous, often to the point of absurdity. Following taxonomic authorities helps us avoid having these arguments on iNat. We can argue about which authorities to follow, but following authorities allows us to skip arguments about each and every paper.
  3. Primary sources are often hidden, while secondary sources are usually open iNat is largely a community of amateurs, and despite the advances made by open-access journals, the bulk of taxonomic literature is still prohibitively expensive for most amateurs to access. Avoiding the primary literature in favor of secondary taxonomic authorities, most of which are freely available on the Web, allows all our users to inspect the sources of taxonomic changes, not just the users with privileged access to the scientific literature.
  4. Following established authorities makes it easier for us to share your data with researchers “What taxonomy do you use?” is often one of the first questions we get from researchers interested in using our data, if we’re even fortunate enough to have that discussion. More often people find our data through aggregators like GBIF, so if we’re using synonymous names that researchers or GBIF doesn’t know about, researchers searching GBIF won’t find our data. Following authorities moderates the pace of taxonomic change in our data and increases the probability that people searching through it by name will find what they’re looking for.

Unfortunately, I’m not sure the authority is ever going to tell you that the range border between two species isn’t where we thought. If the authority can’t resolve the question even in principle, I think you really have to look at other bodies and try to figure out what they are doing. So are North American herp societies, state natural heritage agencies etc. following the new taxonomy? Maybe this will resolve things easily (iNat shouldn’t be switching to a new taxonomy if nobody else is).

Ultimately the point is that iNat wants to follow the consensus among scientists, and not try to determine whether any particular taxonomy is better or worse.

In any case, it shouldn’t be fought over on individual observations, and treatment of the literature should really be consistent across all observations. I see two options:

  1. Just keep all the relevant observations at genus-level until a consensus is obvious or an authority actually resolves things.

If that doesn’t seem reasonable I’d suggest:

  1. Make a journal post laying out the issue, tag in anyone possibly relevant, and try to come up with a consensus for how things should be treated the time being. At that point, people should be following that consensus.

I think this is probably the best way to follow the spirit of the iNat policies when the authorities aren’t useful. Maybe someone else has a better idea.


I actually looked up the two species in question on our authority website. Should have done so initally, sorry:

Speckled Kingsnake
Black Kingsnake

They actually do provide range descriptions, explicitly saying that the Mississippi is the dividing line. So, as far as I can tell, that is how the taxonomy should be treated on iNat, period. If any users feel this taxonomy is wrong, they should take it up at that website, where they seem quite eager to take contributions:
Or at the iNaturalist Reptile Working Group Page:


Charlie and Reuvenm, thanks for the advice! To sum it up, iNat isn’t the place for detailed taxonomic discussions. I can definitely see issues with identifying this particular species complex right along the river since who knows if/how often individuals swim across.


iNat is a great place for taxonomic discussions! Everyone is free to ID as they see things, and where there is a difference of opinion it can be very enlightening to discuss why we take our respective positions, and often new information is presented that can shift your point of view! So my advice on how to handle them, is make your ID as you see fit, and if you feel it is of benefit you can elaborate in the ID comment field, or a standalone comment. That way, others can learn from it all too!


iNat is certainly a great place for taxonomic discussions. But the guidelines are pretty clear that identifications are not the place for taxonomic disagreement.

Under the iNat taxonomy, Lampropeltis nigra explicitly refers to snakes east of the river, and L. holbrooki explicitly refers to snakes west of the river. When you identify something as L. holbrooki on iNat, you aren’t just attaching the name L. holbrooki to that observation. You are attaching the taxonomic concept used on iNaturalist to that observation. Let’s call it [iNat!L. holbrooki].

This is important. It feels like an identification on iNat is attaching a name to an observation. But really, what you are doing is attaching a taxonomic concept to an observation. Most of the time, these two things are exactly the same, because a name can only refer to one taxonomic concept. Unfortunately, Linnaean nomenclature is not perfect in this, in that a single name can refer to multiple taxonomic concepts.

iNat does not (currently) support multiple taxonomies. Identifying an observation as L. holbrooki, is actually saying this is [iNat!L. holbrooki], which is defined as [populations west of the river]. It’s incoherent to identify a snake east of the river as [populations west of the river].

Everyone should be able to agree that currently on iNat, L. holbrooki refers only to snakes west of the river. This is what the authority says, and the iNat guidelines say that we use that authority. If people think that iNat should use some other definition, that’s great! They can say so on individual observations, although it won’t change anything. The best place to take this up is at the authority website, or in the iNaturalist working group project. Or you even argue that iNat should use a different authority, or no authority at all! Such discussion have come up in the past on the Google Group.

But what people should not be doing (based on my interpretation of the guidelines) is identifying while using a different definition than is used on iNaturalist. Of course, this is going to happen all the time when people don’t know that taxonomies have changed, or don’t know what the iNaturalist guidelines say, or are even engaging in some “civil disobedience”. This is an ideal, not an attainable goal.

How far this should be taken is definitely an important question. The linked observation above has a laundry list of many of the most valuable herp identifiers identifying it “wrongly”. People are clearly passionate about this case - it’s probably a good idea to start a discussion at about whether this should be an “explicit deviation”.


My understanding is that the taxonomic tree used in iNat is a determined thing, but as far as what observations are identified as, it is a concensus of what IDs are applied by all identifiers. We can all put different (valid within iNat) IDs and yet none of us could be putting what the system takes as the concensus view. I agree regarding “taxonomic concept”, something that took me a while to get my head around (coming from a novice perspective)

There’s a FAQ item that addresses this issue. It doesn’t explicitly mention range, but it was added to the FAQ based on a very similar case: contentious snake identifications related to taxonomy/range/a swimmable boundary—in that case, Pantherophis alleghaniensis/P. spiloides, which also spurred the creation of this species complex taxon: (P. alleghaniensis + P. spiloides)

From the FAQ:

As much as possible iNaturalist tries to follow secondary taxonomic authorities, for reasons explained here. We understand that not everyone will agree with the current taxonomy on iNaturalist, but we believe it is important that when you add an identification to an observation, you should follow the taxonomy here. This is important because:

  • It ensures we are all talking about the same things. While you may not personally agree with our current definition of Exampelia generica , everyone on iNaturalist will at least understand what is meant by an ID of Exampelia generica .
  • When taxonomy is updated, those updates will be correctly reflected in the ID.
  • It prevents messy taxonomic arguments on observation pages, where they don’t belong.

So if you don’t want to follow iNaturalist’s taxonomy for a taxon, please refrain from adding an ID for said taxon - you can add a polite comment instead. If you have an issue with any taxon on iNaturalist, you can go to the taxon’s page, click on Curate (under the graph) and select “Flag for curation”. There you can write a note (citing evidence), and the site curators can discuss your proposal.

iNaturalist’s taxonomy is a communally-curated synthesis, and thus no one agrees with all of it. If you can’t accept a taxonomy that you don’t completely agree with, iNaturalist is probably not the place for you, and you should instead consider other data recording platforms.


subspecies that potentialy intergrade and are very closely related are in my mind very different from two species that occur on different continents. It’s a balance and we have to use location a lot, but i can’t see any point in classifying subspecies by location, especially if they occur near each other. It’s circular. We mark something as a subspecies based on location and we generate ‘data’ which is then used to reinforce the fact that the subspecies ‘occurs’ in that location. So nothing is gained at all, and the small potential to refine or discover new things about the subspecies range is lost. So what’s the upside? I don’t really understand. (if this spins off discussion i will move it to a new topic)

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agree: it needs a new thread.
But briefly. You would be correct if identifying by subspecies only was the final point. The reality is that most subspecies do have features assisting ID, and the geographical ID is an interim step, like classifying unidentified observations as “plants”. Once categorized an evaluation of morphological features, intermediate characters is possible. In addition is allows an assessment of the intermediate zone, which in some subspecies does not exist, in other species is broad and nebulous, and in some species seems to drift from time to time. In a few species it may be possible that one subspecies is “absorbing” another. All these can be assessed (another cool potential use of iNat), but often the first step is making a first rough cut using recorded distributions, and taking it from there.
Where distribution is the only means to separate subspecies, then I agree with you! Except, that in those cases does the tautology matter? Does it matter in these cases that some users are happy to ID based purely on that one feature?

ok, i moved it to a new thread.

People do this all the time, and it annoys me, i don’t usually bother asking people not t od o it elsewhere and there’s no clearr iNat policy i know of but i won’t agree with subspecies IDs on my own observations without a visible feature, except in rare cases (like one of the two subspecies is a rare island endemic disjunct or something). And I don’t add those IDs for others either. Obviously if you are looking at attributes it’s fine but… even then I usually don’t bother with subspecies.

This is a tough one, because though it seems clear from this discussion that there is a “right answer” on what should be done on iNaturalist (use the secondary authority – the Reptile Database – and thus use the river boundary), the people who strongly disagree with the secondary authority on this particular issue don’t seem to understand (or care about?) this conclusion. People have already mentioned this conclusion and the reasoning behind it in the observation discussions, but that hasn’t slowed down the discussions or altered the direction of the IDs as far as I can tell.

i don’t think trusting a reptile database over field data is a slam dunk choice at all. The point of iNat (among other things) is to document biodiversity, but if you can’t tell a species or subspecies by the photo but are identifying as such anyway, why not just add a casual observation without a photo? Adding data ‘verifying’ range in a published source based on that very source is… circular.


I dunno… we have two spider species that look almost identical, at least to the point that I could not tell from a typical photo which is which. One we have in the North Island, the other in the South Island, seperated by the Cook Straight. The first is Lampona murina and the other is Lampona cylindrata. In the modern descriptions of these size ranges are given, and having found extremely large specimens that fit more with the size of the South Island species, I was sure that location couldn’t be relied upon, but it was the literature that proved to be wrong, as my example was definitely the North Island Lampona murina under the microscope, despite it’s large size! The current position seems to be that we can ID to location, and if we ever find examples of either in the wrong place, then we can go back and review all back to genus.

For birds, we have many subspecies IDd birds here in NZ especially amongst the small passerines, largely because it is known what population was introduced by the acclimatisation societies. Some have a number of possible ssp so it is advisable to stick to species ID unless there are visible features to support the ID.

Adding an observation without a photo would of course not even identify the genus or species. I’m not sure what point you were trying to make there.

All of the options in this L. holbrookia/nigra case seem problematic:

  1. Choose the species based on location. Matches the secondary source chosen by iNaturalist, but seems circular as you say.

  2. Choose the species based on appearance. Directly contradicts the secondary source chosen by iNaturalist, without any supporting evidence.

  3. For any observations near the contact zone that have a (somewhat?) speckled appearance, use only a genus-level ID. Isn’t incorrect in any way, but leaves out information (at the very least, we know the individual is either L. holbrookia or L. nigra).

None of these options seem great, in this particular case. But it sounded to me like the consensus in this discussion was that option (1) was the one that matches iNaturalist’s rules/guidelines.

yeah, i am not trying to be a hardliner or something. I think there are cases where it makes sense, and of course for species you kind of have to do it. I don’t consider every pine species on the planet when I see a white pine in Vermont. But, the example was snakes across a river, which even the Mississippi is only a couple of miles across and with the current things often move across it. Most snakes are good swimmers. Subspecies are tenuous entities that by definition intergrade and are hard to pick apart. With the recent mess of splitters rampaging through taxonomy and declaring nearly all subspecies as separate species, anything remaining a subspecies is usually very indistinct indeed. Granted island endemicism is a little less fluid, and i think island endemics are an example where it’s a bit less problematic.

i’m not saying i am going to go find all the observations of this snake subspecies and knock them back to species but i am saying i don’t think we should do this stuff as a matter of course, and that i won’t do it on my IDs in most cases. The other downside is when you put them to subspecies you lose most of the points on the map on the observation page. I don’t like that either.

the point was that the photo wasn’t sufficient to the level of ID that was being proposed so wasn’t really evidence for that subspecies. Really, it should be research grade to species and casual grade to subspecies. Maybe all subspecies should remain ‘casual’ grade at that level but… i suspect that would piss a lot of people of and wouldn’t fly.

i’m confused. Isn’t the appearance supporting evidence? The bottom line is this is iNaturalist not iTaxonomist. It can be used for some really surprisingly robust data management but the bottom line is, this isn’t hard science entirely backed up by citations. It’s people coming up with reasonable IDs for the snake they find.

that wasn’t something that was clear to me, but i suspect there are some differences by taxa. For instance i mostly look at plants and for those, especially wind pollinated ones, dispersal of genetic material is a lot easier than most animals. If (1) is a consensus i will let this issue drop, but i think users should still be respected if they choose not to do it. We may be able to go taxa by taxa or something, if need be. I know a lot of birders are very anti-subspecies-by-location and i think ebird doesn’t allow the practice? Not that we need to follow ebird, but for plants, i think the practice should be discouraged in the case of grey areas at least for subspecies. And in any event when the two subspecies are very geographically distinct, IDing them doesn’t add any further information because you can just look at the map, see the two clusters 400 miles apart, and know they are different subspecies. Either way you could infer they are distinct non intergrading populations at that point.

My point was that the paper that defines the range boundary as the river explicitly makes the point that appearance is not enough to distinguish the species here. So someone making an ID based on appearance is directly contradicting the taxonomic source that iNaturalist has chosen to use. They are not providing evidence against the taxonomic source, they are just saying that they disagree with it.

That’s a perfectly fine discussion to have, but it should be had (according to iNaturalist’s stated policy) outside of the scope of the specific observation, as @reuvenm explained above.

Note that for this particular case the discussion is not about subspecies but about species, which removes the option of just identifying to the species level.

if there is no way to tell the subspecies apart by appearance, why would anyone try to add IDs to someone else’s observation at subspecies level based on iNaturalist evidence? I personally don’t think that’s an appropriate use of this site, at least not to the point where something becomes ‘research grade’. I guess that is a point of contention but i ask, why do we need or want that sort of inferred ‘data’ here?

Over time as genetic analysis and evidence becomes more ubiquitous, until the possible point in which all phones have genetic sequencers, there will be a period where we realize there are TONS of genetically distinct cryptic ‘species’ that can’t be told apart based on iNaturalist evidence or anything else short of a full genetic scan. I personally think they should be kept as subspecies when this is the case on pragmatic grounds, but since we have no control over taxonomists, this will continue to be an issue. I think we should create taxonomic units that encapsulate all the options that look the same. In the end this is a citizen science website that is extremely powerful and also useful for scientists collecting recon-level data. I use it for ‘real’ science all the time. But it isn’t, i don’t think, a place to be forcing crypitic genetically defined subspecies ID on someone’s photo of a snake they found.

I suppose like many other huge questions we need to resolve this one on iNat one way or another… but this one goes way beyond iNat even. For instance we do lots of plant plots to characterize wetland condition at my workplace. We don’t have genetic sequencers, and even if the different genetic strains of some sedge or willow DO tell you something about the environment, we don’t have the resources to run genetic analysis on each Carex stricta plant and won’t any time soon. So, it goes on the data sheet as Carex stricta. I can’t see holding iNat to a higher standard here.

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I should note that I’m not sure the current iNat policy is necessarily exactly right here - but if following it, I think it’s pretty unambiguous as to the right answer here.