Bigtooth Flathead

description

Description. Counts and measurements shown in Table 6. Data for all specimens presented first, followed by holotype condition in parentheses. Snout, area anteroventral to eye, interorbit, and occipital and lower half of suborbital regions naked. Interorbit narrower than orbital diameter in 99.7 mm SL or smaller specimens, wider in larger specimens (including holotype). Upper iris lappet broad, bilobed; lower weakly convex. Nasal, preorbital, preocular, suborbital and supplemental preopercular spines absent. Lower preopercular spine slightly shorter than upper in 99.7 mm SL or smaller specimens, longer than upper, not reaching opercular margin in larger specimens (including holotype). Interopercular flap absent; margin of interopercle scalloped. Maxilla usually reaching to or slightly beyond anterior margin of pupil in 99.7 mm SL or smaller specimens, to middle of eye in larger specimens [up to 426 mm SL (including holotype)] and to posterior margin of eye in largest (460 mm SL). Upper jaw with one or two (two) large caniniform teeth anteromedially. Palatine teeth in two rows, villiform in outer row, moderate or large caniniform (large caniniform) in inner row. Vomerine teeth usuall

Taxonomic revision of the flathead fish genus Platycephalus Bloch, 1785 (Teleostei: Platycephalidae) from Australia, with description of a new species

diagnosis

Diagnosis. A species of Platycephalus with the following combination of characters: second dorsal-fin rays usually 14; anal-fin rays usually 13; caudal-fin rays 9 – 11 (usually 10 – 11); pored lateral-line scales 59 – 68; orbital diameter 11.3 – 21.8 % HL; interorbital width 9.3 – 17.5 % HL; postorbital length 50.0 – 61.1 % HL; snout, area anteroventral to eye, interorbit, occipital and lower half of suborbital naked; one or two large caniniform teeth anteromedially on upper jaw; margin of interopercle scalloped; fleshy sensory tubes from suborbitals and preopercle slightly developed, partly covering dorsal and ventral margins of cheek region.

Taxonomic revision of the flathead fish genus Platycephalus Bloch, 1785 (Teleostei: Platycephalidae) from Australia, with description of a new species

discussion

Remarks. As pointed out by Knapp (1991), P. chauliodous has one fewer anal-fin rays (13 – 14, usually 13) than second dorsal-fin rays (14 – 15, usually 14), an unusual characteristic in Platycephalus (usually the same number of second dorsal- and anal-fin rays). Also unusual is a scalloped interopercular margin that is found elsewhere only in P. orbitalis among species of Platycephalus. Apart from the above characters, P. chauliodous resembles P. aurimaculatus, P. conatus and P. richardsoni in having one or two large caniniform teeth anteromedially on the upper jaw (large caniniform teeth absent on upper jaw in other species of Platycephalus). The first-mentioned can be easily distinguished from the other three species in having 9 – 11 caudal-fin rays (usually 10 – 11) (vs. 12 or 13), 59 – 68 pored lateral-line scales (75 – 90 in P. aurimaculatus, 70 – 81 in P. conatus and 65 – 74 in P. richardsoni), the occipital region naked (vs. scaled), and fleshy sensory tubes from the suborbitals and preopercle slightly developed, partly covering the dorsal and ventral margins of the cheek region (vs. tubes not covering cheek region). The orbital diameter / interorbital width relationship is

Taxonomic revision of the flathead fish genus Platycephalus Bloch, 1785 (Teleostei: Platycephalidae) from Australia, with description of a new species

distribution

Distribution. Known only from southwestern Australia, from Great Australian Bight (149 ° 16 ’ E), WA to near Perth (31 ° 50 ’ S), infrequently taken on shallow coastal reefs in depths from 4 to ca. 40 m (e. g., Hutchins & Swainston, 1986; Knapp, 1991; Hoese et al., 2006; this study). Size. Previously known maximum length 46.5 cm (Hutchins & Swainston, 1986). One specimen examined during the present study measured 460 mm SL (541 mm TL). TABLE 6. Comparison of counts and proportional measurements of Platycephalus chauliodous. * Usually 10, nine in smallest specimen.

Taxonomic revision of the flathead fish genus Platycephalus Bloch, 1785 (Teleostei: Platycephalidae) from Australia, with description of a new species