Arion subfuscus/fuscus species complex

Hi! I’m new to both iNat, taxonomy and gastropods and had a question to learn a bit more on all three.

It seems that Arion subfuscus and Arion fuscus can only be distinguished anatomically through dissection, and can be considered a species complex. I can’t find any species A. fuscus/subfuscus species complex on iNat, though. I assume that this prevents many A. fuscus/subfuscus observations from reaching research grade and getting stuck at subgenus Mesarion.

Is there a reason for the situation or have I misunderstood something?



There is an option to add species complexes to iNat’s taxonomy. Generally for these sorts of questions, you should flag the parent/closest taxon for curation and begin a conversation there. If the complex is recognized in the literature it will probably be added. I’d flag it for you but I’m on mobile right now P:

Also, observations can reach RG at Genus level or below. For this to happen, you have to go into the Data Quality Assessment, and check Yes, the ID can no longer be improved. It is better to do this than to try and push an observation to a finer ID when there isn’t evidence ;)


Thank you for the introduction! I just flagged Mesarion. Good to know even genus-level can be RG.

1 Like

I’m not super familiar with these species (I usually just put genus and leave it at that) but I know that many species in the genus are best IDed by dissection (true of many terrestrial gastropods in general). I know other people will ID to subgenus, but if these are the only 2 species needing dissection in the subgenus a complex might be helpful. I’ll look into this a little more when I get back to a laptop. :) Are you thinking of a particular region?

1 Like

Thank you Thomas! I’m in Sweden, and only one of the two species seems to occur here. I haven’t been able to find a source corroborating that, though.

This is the flag:

This topic was automatically closed 60 days after the last reply. New replies are no longer allowed.