The name Heikeopsis is taken from the scientific name of a species of Japanese crab called Heikeopsis Japonica, otherwise known as the Heikegani, or "Samurai Crab". The hypothosis goes that "the crabs with shells resembling Samurai were thrown back to the sea by fishermen out of respect for the Heike warriors, while those not resembling Samurai were eaten, giving the former a greater chance of reproducing. Thus, the more closely the crabs resembled a samurai face, the more likely they would be spared and thrown back.
Link to the challenge: https://www.artstation.com/contests/feudal-japan/challenges/55/submissions/34300