Lontra canadensis periclyzomae, the Haida Gwaii River Otter, is a ssp. not currently in iNat. I’m not sure how well-defined it is, but I’d assume it warrants adding. Haida Gwaii is notably well-known for its high rate of endemism.
Most in-depth reference I could find: tiny.cc/dd3tcz
I asked a couple of folks knowledgeable or expert in river otter about this. The subspecies in river otter are not well worked out in terms of which should be considered valid, and genetic work has not been done on most forms including this one. But there is apparently no publication that specifically “sinks” this subspecies, so it should probably be considered valid until otherwise indicated.
Looks like the taxon has now been added to iNaturalist, so I am going to close this topic.
Any time you find another taxon missing, the best way to get it added (if the External Sources option doesn’t find it for you) is to Flag for Curation it’s parent taxon, and ask for a curator to add it. Leave supporting information for it in a comment on the flag.