Cryptic Species Complexes and Range Expansion

Hi - for my first butterfly observation, I just had to pick a cryptic species complex, the Common/White Checkered-skipper complex.

Generally I prefer non-destructive field observations, leave specimen collection to the scientists. Especially with butterflies where here in California, several species are presumed extinct and others are in notable decline.

One issue I can not demand people be aware of but that I want people to be aware of, with a cryptic species complex for a mobile species, using “range maps” to identify the species should in many cases be avoided.

With the Common Checkered-skipper and the White Checkered-skipper, from what I understand it is impossible to distinguish females without genetic analysis. Males can be distinguished but only by examining their reproductive organ. So when a butterfly in that complex is posted here, range is often used to distinguish them.

However with butterflies and from what I have read this species in particular, range maps are not reliable. The White Checkered-skipper prefers warmer climates, but in the United States in response to climate change, its range has been demonstratably moving north often replacing Common Checkered-skipper populations. Unless range information is based upon very recent surveying of a statistically significant number of males that are only only species or the other, the reality is we can highly suspect one subspecies or the other but we can not know for certain.

I politely ask (but have no authority to demand) people when a species from such a cryptic species complex is posted with the identification as the species complex rather than as a species, please do not declare it one species or the other based upon range maps alone, unless you know of very recent scientific surveys in that region that can be cited. The ranges are changing.

Thank you.


While I generally agree with this, iNat’s taxonomy doesn’t have very many species complexes at the moment and it will take significant effort on the part of the relevant curators to get them up and running. This will also naturally require users to re-identify the relevant observations.

EDIT: I want to clarify my position. I agree we should emphasize identification of species complexes, I’m just saying that this won’t be simple or easy to implement


I’m on the other side of the fence on this one. If you have ranges that are clear and distinct enough to ID based on, then use them, but if there is an overlap or “could be either” zone, then that has to be taken into account also. I should add though, that range alone is like only looking at the eyes, or only counting the legs… it is one “character” out of many, and particularly in situations such as you describe I don’t think it is wise to take any single character as being deterministic, but rather a group of characters.

If you think about ranges, nearly every single taxa has had it’s “actual” range completely munted by human activity and habitat destruction anyway!


Is there a set of guidelines on how to handle species complexes? Comes up with fungi all the time.
For example: Chanterelles. Cantharellus cibarius was scientifically deemed incorrect in my region (European species, but I live in Canada), it was broken into about 4-5 species which are quite hard to visually distinguish. Would one still call it part of a “Cantharellus cibarius” clade, or would you just be limited to “Cantharellus?”
Many many examples where I’m not sure how to treat clades

Yes, this is a frequent issue with many fungi, especially now when the cryptics are revealed by DNA. The same happened with Fomitopsis pinicola which now is only from Eurasia but not from America anymore. I would say that in your case the genus level is enough though we do know that it is part of the Cantharellus cibarius clade; one day someone may find ways to ID them from photos. (In Europe, in Paxillus several new species have been described near P. involutus and P. rubicundulus; still IDs are done to these two which are in fact a group of species both.) But, we can identify only to that level that is possible from photos, and in many cases that is the genus level only…

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