This might be a relative of our pill bugs? But there is probably a lot more evolution between them than between, e.g., horses and sharks. Which, by the way, is also bigger than between bony fish and sharks.
I had no idea something like this size and related existed in the sea! Incredible! I wonder now what the evolutionary tree looks like.
Edit: Corrected Family -> Order - oops! Thank you pvaldes.
It seems there is an opportunity here, crouching like a cat, to dedicate one of this new species to Hayao Miyazaki. Bathynomus ohmu seems an pretty convenient name also. Maybe the next.