Copetarsi (lit. "paddle ankle") are a clade of semiaquatic Platydontia native to equatorial marshes.
A member of the Archeplatydontia branch, Copetarsans are native to marshes and bogs. Their legs are shorter compared to other Platydonts, and have wide feet to help them more effectively swim.
Able to hold their breath for several minutes at a time, Copetarsans feed on the various amphibious and aquatic species within their habitat, such as Myzostomes, Metaxypods, and river-dwelling Acanthopods.
The size comparison charts in Part 7 showed a Copetarsi with a total body length of roughly 0.5 meters.