About Platax orbicularis (Forsskål, 1775)
Platax orbicularis, commonly known as the orbicular batfish, is characterized by the round, very deep, highly compressed bodies of adult individuals. Larger adults measuring over 40 cm (16 in) in total length have an indented snout with a bony intraorbital protuberance. Each side of the lower jaw bears five pores. Both jaws have bands of thin, flattened, tricuspid teeth, with the central cusp approximately twice as long as the lateral cusps. No teeth are present on the roof of the mouth. The dorsal fin is supported by 5 spines and 34 to 39 soft rays, while the anal fin contains 3 spines and 25 to 29 soft rays. Adult orbicular batfish are silvery grey, with black vertical bars passing through the eye and pectoral fin. Their dorsal and anal fins are yellowish with black margins, and small black spots may sometimes be scattered across their flanks. Small juvenile orbicular batfish are reddish brown, marked with irregular black spots and blotches, plus small white ocelli with black margins on the body. A small black spot sits at the base of the last 3 rays of both the dorsal and anal fins, and the caudal fin is transparent except for its reddish brown base. The maximum published total length for this species is 60 cm (24 in). Orbicular batfish are native to the Indo-Pacific region. Their native range extends from eastern Africa, including South Africa, Madagascar, the Mascarenes, and the Seychelles, north into the Red Sea, east through the Persian Gulf, and east to Micronesia as far as the Tuamotu Archipelago. The native range reaches north to southern Japan and south to northern Australia. In Australian waters, this species occurs at Ashmore Reef in the Timor Sea, as well as at Christmas Island and the Cocos (Keeling) Islands in the eastern Indian Ocean. On the Australian mainland, orbicular batfish are found from Shark Bay in Western Australia, around the northern tropical coast, and south along the east coast almost to Sydney. This species inhabits shallow, protected coastal waters, including mangroves, coral reefs, and deeper areas with silt substrates. Juveniles typically hide in mangroves and protected lagoons, and often stay among floating flotsam where they mimic dead leaves drifting in the water column. Orbicular batfish have an introduced recorded range in the Western Atlantic off southern Florida, most likely originating from deliberate release from aquariums.
