Cryptic Flatworm

Description

Background colour variable; mottled olive green to lime green and white, large irregular brown and olive green spots on the margin, large irregular orange-brown spots and white dots scattered over dorsal surface, darker medially. Margin narrow, yellow. Gut diverticula usually green. Largest animals with narrow interrupted brown margin and large transverse cream-white bands. Ventral surface light olive green. Pseudotentacles square and ruffled. Cerebral eyespot in clear, oval area with up to 100 eyes. Size range 12 x 7 mm (immature) to 40 x 18 mm (mature).

Distribution

Indo-Pacific Ocean from Persian Gulf (Iran, Kish Island) to Indonesia, Philippines and West Australia.

Habitat

Pseudobiceros kryptos is usually found on colonial ascidians under rubble on the reef crest or reef slope. P. kryptos is free swimming flatworm. P. kryptos is the only polyclads which actively swim with exaggerated undulations of its ruffled margin. This, along with flamboyant coloration, is thought to be aposematic or warning behavior advertising their suspected unpalatability to visual predators such as fish.