OK, new trivial fact (I think it hasn't been told, but I asked the question)

I've heard the meaning of Thamnophis. I've heard the english meaning of many of the species names such as sirtalis, radix, etc. Some of the species names refer to the person who first described the species on paper. I always wondered what concinnus meant. At first my gut told me it referred to the orange/red color but that's not it. If it was called T.s. rufus or T.s. rutilus then yes, that would refer to the color as those latin words refer to the color red.

I finally found out what concinnus translates to:

to sing together, celebrate.

I don't recall any garter snakes singing together or alone. Sure, concinnus get together but generally in less numbers than other garters in their range with which they share dens.

Ordinoides is pretty self explanatory since the english word "ordinary" is from the latin word. Basically, an extremely common and plain snake is to be assumed by the species name and that would be pretty accurate.

What I don't understand is how Oregon red-spotted garter snakes came to be named concinnus. to sing together, celebrate.

I'm going to go out on a limb here and say that perhaps the red spots looked "festive" when compared to the other drab, ordinary snakes in their range?