扁船蛸-1

This species is the largest one of living argonautids, the shell length may be over 45 cm. They are living in topical and sub-tropical oceans worldwide. The argonautids are the only living octopus that creates paper thin testa. They have significant sexual dimorphism. Only the female makes a shell. The thin and fragile shell consists of calcium. Male argonautids don’t have any shell, and body length only 1/20 of female’s, smaller than 2 cm.