I was researching my tribe's clan history and came across something interesting. Osages, like most American Indian tribes, name their clans after either mythological creatures, or common animals (typically with a mythological backstory for the choice).
One of the other subclans caught my eye: "Puma in the Water". This appears to be a reference to a common American Indian mythological character, Underwater Panther. I had never previously heard of this creature.
Apparently, he is the opposite and nemesis of Thunderbird (which I had heard of)*. He's not an actual panther, but rather an aquatic hybrid creature with a feline body, but also horns, scales, and a very long tail.
However, every reference to Underwater Panther I could dig up was in the mythology of Great-lakes area Algonquin-speaking tribes. Osages are not Algonquians, but rather Mississippi Valley Sioxans. And yet, there Underwater Panther is in my tribal history.
Wikipedia does now mention some possibility of a connection with the Mississippians, but completely unattested. My tribe maintains that the Middle Mississippians were their ancestors, and there does seem to be some consensus that at least some of them were probably Siouxan. That's about the best breadcrumb I have.
So the question here is exactly how widespread was Underwater Panther mythology among the Native American tribes? What nations featured it? Is he everwhere that has Thunderbird as well?
* - Yes, Osages have a clan associated with Thunderbird as well.