Indo-Pacific: Known from the Gulf of Aqaba, Comoro Islands and Mauritius to southern Japan, the Philippines, Caroline Islands, northeastern Australia, New Caledonia, Fiji, Tonga, American Samoa and the Society Islands.
In Australia, recorded from about Exmouth (Western Australia) to the English Company Islands (Northern Territory). Elsewhere in the South China Sea - Vietnam, The Philippines, China, north of Waigeo, the Bali Sea and the Timor Sea.
Indo-West Pacific: three known specimens from Natal, South Africa; also from north and northwestern Australia, and possibly extending to western Papua New Guinea. Reported from Samoa
Indo-West Pacific: widespread, from off Natal, South Africa to Karachi, Maldives, South China Sea, Philippines, Irian Barat (Teluk Berau), Northwest Shelf of Australia, Timor and Arafura seas, Great Barrier Reef, Guadalcanal and Tonga.
Western Pacific: southern Japan, South China Sea, Philippines, northwest shelf of Australia through Timor and Arafura seas.
Characteristics
Onigocia is distinguished from other flathead genera by having finely serrated suborbital ridges and in the typically having less than 40 pored scales in the lateral line.[9] These are small flatheads with the largest species being the midget flathead (O. spinosa), with a maximum published total length of 25 cm (9.8 in), while the smallest is O. grandisquama, which has a maximum published standard length of 6.2 cm (2.4 in).[5]
^Imamura, H. (2016): Rediagnosis of Onigocia grandisquama (Actinopterygii: Perciformes: Platycephalidae) and Comparison with Congeners. Species Diversity, 21 (2): 151–159.