@redgarter Here's another from the same paper. It almost appears to support subspecies, but doesn't explicitly say it. Johnson et al. (2018) was a similar study: both looked at shell shape, geography, and DNA. However, Johnson et al. (2018) used nuclear sequencing in addition to 2 types of mitochondrial sequencing (Lopes-Lima et al. [2019] just did the 2 mitochondrial types). Their results would not support subspecies, but also didn't look at much morphology.

Also tagging @srichard89, who brought this up, and top IDer @dbarclay.

Ideally both would be included, along with other factors like geography, habitat, behavior, etc. It's pretty rare to see all those though, and it's up to personal discretion whether you accept any given taxonomic conclusions regardless of how they're reached.

Ah well I was more talking theoretically in the broad sense. iNat prefers to follow external sources for taxonomy, and so we use MolluscaBase for mollusks. This merge is consistent with MolluscaBase. I just didn't want to start merging a whole bunch of names when there are folks on iNat who know way more about these animals than I do. I've ruffled feathers before and would prefer to avoid that again. :)