Notched Flathead, Onigocia macrocephala (Weber 1913)

Notched Flathead, Onigocia macrocephala. Source: Australian National Fish Collection, CSIRO. License: CC BY Attribution-Noncommercial


A small light brown to brownish-red flathead becoming pale below, with about four dark bands across the back, a pale anal fin, and brown spots or blotches often forming bands mostly on the other fins.

Until recently in Australia, the Notched Flathead was misidentified as Onigocia macrolepis, a species that occurs from The Philippines, north to southern Japan, Taiwan and Hong Kong - and not found in Australian waters.

Cite this page as:
Onigocia macrocephala in Fishes of Australia, accessed 23 Jul 2024,

Notched Flathead, Onigocia macrocephala (Weber 1913)

More Info


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.

Inhabits coastal and continental shelf waters to depths of about 30-140 m.


Dorsal fin I+VII-VIII, 10-12; Anal fin II, 11-12; Caudal fin 9-10 (branched rays); Pectoral fin 21-23; Pelvic fin I, 5; Lateral line scales 34-39 (pored scales); Gill rakers 5-7. 

Head large (38.8–42.3% SL); a single ocular flap present, usually extending slightly beyond hind margin of orbit; a few or several small and short papillae on posteromedial portion of eye in larger specimens; upper iris lappet short and branched; lachrymal with two distinct antrorse spines anteriorly and a notch on suborbital ridge below eye; no interopercular flap (Imamura 2012).


Body light brown to brownish-red above, pale below; back crossed by about 4 dark bands. Anal fin pale, other fins mostly with brown spots or blotches, often forming bands.


Carnivore, presumably feeding on fishes and crustaceans.


Little is known of the biology of this species.


May be taken as incidental bycatch in trawls.


Imamura (2012) determined that specimens from Australia previously identified as Onigocia macrolepis (Bleeker 1854) are O. macrocephala (Weber 1913).

Similar Species

Onigocia macrocephala is similar to O. grandisquama, O. macrolepis and O. spinosa in having 9–10 caudal fin rays, a single gill raker on the upper arch, a single ocular flap, a short and branched upper iris lappet, lachrymal with two distinct antrorse spines anteriorly, and no interopercular flap (vs. the combination of characters absent in others). The notch on the suborbital ridge below the eye is found only in O. macrocephala and O. macrolepis. O. macrocephala differs from O. macrolepis in having a larger head (38.8–42.3% SL in O. macrocephala vs. 35.6–38.4% SL in O. macrolepis). Onigocia macrocephala also has a single ocular flap usually extending slightly beyond the posterior margin of the orbit (not reaching its posterior margin in O. macrolepis) and a few or several small and short papillae on the posteromedial portion of the eye in larger specimens (vs. papillae absent in O. macrolepis). The papillae are not seen in all other members of the genus Onigocia

In addition, numbers of pectoral fin rays and gill rakers are helpful to separate O. macrocephala from O. macrolepis [21–23 (mode 22) and 5–7 (6) in total in O. macrocephala vs. 19–22 (21) and 4–6 (5) in O. macrolepis], although overlaps are recognized between the two species (Imamura 2012).

Species Citation

Platycephalus macrocephalus Weber 1913, Die Fische der Siboga-Expedition 57: 508, fig. 107. Type locality: North of Waigeo [Waigiou] (0°02.6'S, 115°24.3'E), depth 100 m, lectotype.

Notched Flathead, Onigocia macrocephala (Weber 1913)


Gloerfelt-Tarp, T. & Kailola, P.J. 1984. Trawled Fishes of Southern Indonesia and Northwest Australia. Jakarta : Dir. Gen. Fish. (Indonesia), German Tech. Coop., Aust. Dev. Ass. Bur. 406 pp. (as Onigocia macrolepis)

Imamura, H. 2012. Validity and redescription of the flathead fish, Onigocia macrocephala (Weber, 1913) (Teleostei: Platycephalidae). Zootaxa 3450: 23-32

Knapp, L.W. 1999. Family Platycepalidae. pp. 2385-2421 in Carpenter, K.E. & Niem, T.H. (eds). The Living Marine Resources of the Western Central Pacific. FAO Species Identification Guide for Fisheries Purposes. Rome : FAO Vol. 4 2069-2790 pp. (as Onigocia macrolepis)

Knapp, L.W., Imamura, H. & Sakashita, M. 2000. Onigocia bimaculata, a new species of flathead fish (Scorpaeniformes: Platycephalidae) from the Indo-Pacific. Special Publication J.L.B. Smith Institute of Ichthyology 64: 1-10

Paxton, J.R., Hoese, D.F., Allen, G.R. & Hanley, J.E. (eds) 1989. Zoological Catalogue of Australia. Pisces: Petromyzontidae to Carangidae. Canberra : Australian Government Publishing Service Vol. 7 665 pp. (as Onigocia macrolepis)

Paxton, J.R., Hoese, D.F., Gates, J.E. & Bray, D.J. 2006. Platycephalidae. pp. 933-948 in Beesley, P.L. & Wells, A. (eds). Zoological Catalogue of Australia. Volume 35 Australia : ABRS & CSIRO Publishing Parts 1-3 2178 pp. (as Onigocia macrolepis)

Sainsbury, K.J., Kailola, P.J. & Leyland, G.G. 1985. Continental Shelf Fishes of Northern and North-Western Australia. Canberra : Fisheries Information Service 375 pp. figs & pls. (as Onigocia macrolepis)

Weber, M. 1913. Die Fische der Siboga-Expedition. Sitzungsberichte der Akademie der Wissenschaften in Wien. Mathematisch-Naturwissenschaftliche Klasse 57: 1-710 123 figs 12 pls See ref at BHL

Quick Facts

CAAB Code:37296025

Danger:Venomous spines

Depth:1-150 m

Fishing:Trawl bycatch


Max Size:about 10 cm SL

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