Callichimaera perplexa is a species of small crabs known from the Cretaceous Churuvita Group of Colombia and the Frontier Formation of the United States.

The specific name is derived from the Latin "perplexus", meaning intricate (or perplexing in that manner), a reference to the complex anatomical affinities this species displays.

This includes features like large compound eyes,[5] a small fusiform body, and thin mouth parts.

[2][6] Because Callichimaera has large paddle-like legs, it was probably an active swimmer, opposed to predominantly living on the seafloor.

[7] An in-depth study of the crab's eyes indicated that Callichimaera was an active predator living high in the water column.