Pseudobiceros kryptos (Newman & Cannon, 1997).

Abstract

Pseudobiceros kryptos is usually found on colonial ascidians under rubble on the reef crest or reef slope. P. kryptos is free swimming flatworm. New record is given from Persian Gulf (Iran, Kish Island). 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. P. kryptos is in part: "Background color 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. Cerebral eyespot in clear, oval area with up to 100 eyes. Maximum length is 80 x 25 mm in Persian Gulf (Iran, Kish Island). Size range 12 x 7 mm (immature) to 40 x 18 mm (mature) in other sites. Male pores well separated. One animal was found with several symbiotic copepods (Pseudoanthessius sp.) which appeared to be living near the pharynx. Named from the Latin (masculine) kryptos = hidden, for its cryptic coloration.