I know iNat has been very helpful by creating some species groups to include sister taxa that are difficult or impossible to identify based on the typical evidence provided in iNaturalist records. Because they are sister taxa, it is easy to group them in one clade/node.
But I’ve run up against a species identification problem pair for non-sister species. - the Rough and Smooth Earthsnakes.
They had historically been the only two members of the genus Virginia and since they are sometimes difficult to ID from photos, we had the fall back identification of Virginia sp…
But now that recent evidence has shown that they are not a monophyletic clade, one of the species (Rough Earthsnake) has been moved back to its original genus Haldea. So there is no taxonomic unit that includes these two snakes other than the subfamily natricinae. The problem is that natricinae is a cosmopolitan group of 37 genera and several hundred species.
Yet I’m 100% sure from the photos that the snake is either Virginia valeriae or Haldea striatula.
I’m sure there are a lot of other examples where we have to resort to highest common taxon when we know more specifically what we are dealing with. Mimicry and convergence would be expected to create this problem.
Is there a way we can give an “either/or” ID for these sorts of non-sister taxa?
If I recall correctly, these two species overlap broadly in geographic range so location might not be helpful in many cases in making a call on which species it’s most likely to be.
Adding comments to indicate that it’s one of two species and relegating a record to Natricinae might be only option … at least until the taxonomy changes again.
Does iNat support tribes in classification? If the two genera are sister genera within natricinae that might be a solution, someone would just have to name it.
Of course if the two species still wouldn’t form a monophyletic tribe and other species are genetically between them then that wouldn’t work either.
I think Tribe Thamnophiini includes these two genera, and a bunch of others, and would have to be created in the iNat taxonomic framework. Not sure it would really narrow it down by much.
Assuming the below paper is still the accepted phylogeny, it looks like Virginia and Haldea aren’t next to each other on the tree anyway, there’s several other species more closely related to V. valeriae than H. striatula. So never mind the tribe idea. But I guess Thamnophiini would at least narrow it down to fewer species than Natricinae.
In the link you provided, the two species are sisters or at least congeners. The problem I’m dealing with is two species that are not each other’s closest relatives and don’t form a monophyletic group.
The only solution would be an ID category which doesn’t fit on any phylogeny as an entity. I’m not sure if that would work in the taxonomic framework iNat uses.
Here’s a tree showing their current phylogenetic arrangement (Virginia striatula was elevated to the genus Haldea based on this tree). You can see there is no way to group them other than the subfamily grouping.
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