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(McCulloch, 1914) Ratabulus diversidens Freespine Flathead
[CAAB 37 296011]

Distribution Map see an interactive map here (new window)

Distribution, ecology and habitat:

Continental shelf and upper slope of northern Australia, from off North West Cape to off Port Hedland in the west, and from off Sydney, northward to at least Brisbane in the east. Eastern distribution requires further examination. Distributed internationally from East China Sea, South China Sea, and northern Philippines. Demersal at depths of 9-261 m.

Size:

To about 35 cm TL, commonly to 30 cm TL.

Characteristics:

D IX,I or I,VIII,I,  11; A 11 or 12 (usually 12); P 18-20 (usually 19 or 20); V I, 5; Llat (pored) 52-55 (usually 53 or 54).

Body elongate, slightly depressed. Head elongate (length ~41-42 % SL), moderately depressed, strong stria over temporal and upper preopercular region; supraorbital ridge smooth anteriorly, serrated posteriorly; eyes large (~20% HL), no ocular flap; suborbital ridge with numerous spines and serrations, largest 2 below eye; preocular and preorbital spine present; teeth in jaws and on palate long, needle-like, some depressible, vomerine teeth in 2 parallel longitudinal bands; two or three preopercular spines, upper longest, with basal accessory spine, third spine rarely present, minute; interopercular flap absent; gill rakers on first arch 7-9 (usually 7 or 8). Scales small, finely ctenoid dorsally, cycloid ventrally, covering body and most of head behind eyes; Diagonal scale rows slanting backward above lateral line 64 to 79. Lateral-line scales 52 to 55 (usually 53 or 54), anterior 2 to 8 scales bearing a small spine. First dorsal fin spinous with short base, short first spine variably present, detached, last spine very small, detached from preceding spine. Second dorsal fin with moderately long base, anterior rays longest, nearly as long as longest first dorsal spines. Anal fin similar in shape, opposite and slightly longer-based than second dorsal fin. Caudal fin truncate to slightly rounded. Pectoral fins moderate in size. Pelvic fins long, based below centre of pectoral fins, reaching past anal fin insertion.

Colour:

Grey to light tan above, with several indistinct bands across back, orange or brown spots on head, distinctive orange or green spots on upper body in large specimens; purple blotches along midline; whitish below. Caudal fin pale white, with a submarginal dark band; pectoral fin with fine brown flecks; pelvic fin with fine dark spots.

Fisheries:

Reportedly taken in trawls.

Conservation Status:

None.

Other common names:

Orange-freckled Flathead.

Original citation:

Insidiator diversidens McCulloch, 1914, Biol. Results "Endeavour" 2(3), off Port Stephens Lighthouse, New South Wales, Australia.

References:

Eschmeyer, W.N. (2008) The Catalogue of Fishes on-line. (California Academy of Sciences: San Francisco) Available from: http://www.calacademy.org/research/ichthyology/catalog/fishcatmain.asp (10 March, 2008).

Gloerfelt-Tarp, T. & Kailola, P.J. (1984) Trawled Fishes of Southern Indonesia and Northwestern Australia. Canberra: Australian Development Assistance Bureau, 406 pp.

Hoese, D.F., Bray, D.J., Paxton, J.R. & Allen, G.R. (2006) Fishes. In: P.L. Beesley & A. Wells (eds) Zoological Catalogue of Australia Volume 35. Parts 1-3. Australian Biological Resources Study and CSIRO Publishing, 2248 pp.

Hutchins, J.B. (2001) Checklist of the fishes of Western Australia. Records of the Western Australian Museum Supplement 63: 9-50.

Imamura, H. (1996) Phylogeny of the family Platycephalidae and related taxa (Pisces: Scorpaeniformes). Species Diversity 1(2): 123-233.

Knapp, L.W. (1999) Family Platycephalidae, flatheads, pp. 2385-2421. In: K.E. Carpenter & V.H. Niem (eds). FAO Species Identification Guide for Fishery Purposes. The Living Marine Resources of the Western Central Pacific. Volume 4: Bony Fishes Part 2 (Mugilidae to Carangidae). Food and Agriculture Organization of the United Nations, Rome.

Sainsbury, K.J., Kailola, P.J. & Leyland, G.C. (1985) Continental Shelf Fishes of Northern and North-Western Australia. Canberra, C.S.I.R.O. Division of Fisheries Research, 375 pp.