Platycephalus conatus Waite & McCulloch, 1915

Imamura, Hisashi, 2015, Taxonomic revision of the flathead fish genus Platycephalus Bloch, 1785 (Teleostei: Platycephalidae) from Australia, with description of a new species, Zootaxa 3904 (2), pp. 151-207 : 181-183

Platycephalus conatus Waite & McCulloch, 1915

Common English name: Deepwater flathead ( Fig. 22 ; Table 8 )

Platycephalus (Neoplatycephalus) conatus Waite & McCulloch, 1915: 466 , pl. 12, figs. 1–3, 5 (type locality: Great Australian Bight, SA, Australia).

Neoplatycephalus conatus: May & Maxwell, 1986: 271 , unnumbered fig.; Knapp, 1991: 29, tab. 1; Kuiter, 1994: 517, fig. 460.

Platycephalus conatus: McCulloch, 1929: 401 ; Last et al., 1983: 332, fig. 28.19; Paxton & Hanley, 1989: 468; Hoese et al., 2006: 941; Imamura, 2006: 304, tab. 1; Gomon, 2008: 519, unnumbered fig.

Platycephalus speculator (not Klunzinger, 1872): Coleman, 1980: 112, unnumbered color fig.

Neoplatycephalus speculator (not Klunzinger, 1872): Scott et al., 1980: 167, unnumbered fig.

Material examined. Paratypes (2 specimens, 243–269 mm SL, from southern Australia): AMS I. 13649, 243 mm SL, Great Australian Bight, 146–219 m depth, Apr. 1913; AMS I. 13650, 269 mm SL, Great Australian Bight, 145–220 m depth, Apr. 1913.

Other specimens (17 specimens, 158–607 mm SL, from southwestern and southern Australia): AMS I. 12393, 236 mm SL, AMS I. 2394, 227 mm SL, Investigator Strait, SA (35°25’S, 137°22’E), 1912; AMS I.18710-007, 2 specimens, 158–174 mm SL, Great Australian Bight, WA (33°20.8’S, 127°29.7’E), 300–310 m depth, 27 Feb. 1976; AMS I.25551-001, 303 mm SL, Great Australian Bight, SA (37°45’S, 139°45’E), 11 Nov. 1984; CSIRO H1919-05, 486 mm SL, Great Australian Bight, SA, 130 m depth, Feb. 1988; CSIRO H4133-04, 550 mm SL, Great Australian Bight, WA (32°S, 129°E–33°S, 131°E), 130 m depth, Jan. 1996; CSIRO T 529, 337 mm SL, Great Australian Bight, WA (32°32’S, 129°05’E – 33°22’S, 128°57’E), 235 m depth, 22 May 1983; CSIRO T 532, 179 mm SL, Great Australian Bight, SA (33°22’S, 128°57’E), 222 m depth, 22 May 1983; NMV A 2916, 291 mm SL (dissected by Imamura, 1996), 29 km south-southwest of Lakes Entrance, Vic (38°S, 147°59’E), 53 m depth, date unknown; NMV A 9033, 166 mm SL, 120 km south-southwest of Middini Beach, Great Australian Bight, WA (33°13’S, 127°02’E), 98–147 m depth, 14 Feb. 1990; NMV A 9488, 410 mm SL, 95 km southwest of Geraldton, WA (29°21’48”– 29°20’24”S, 113°46’36”– 113°45’54”E), 530–942 m depth, 6 June 1991; NMV A 24526 , 191 mm SL, Great Australian Bight, WA (33°S, 127°E), 160 m depth, 7 Dec. 2001; NMV A25185 -001, 365 mm SL, Port Lincoln, Spencer Gulf, SA (34°44’S, 135°52’E), 28 July 2003; NSMT-P 112677, 607 mm SL, Great Australian Bight, SA (33°18.8’S, 130°8.7’E), 157 m depth, 30 Nov. 1975; QM I. 22822, 237 mm SL, off Portland, Vic (38.2°S, 141.4°E), 140 m depth, date unknown; WAM P.28617-005, 432 mm SL, SA (35°00’S, 117°52’E), 1975.

Paratypes Non-types n = 2 n = 17 SL (mm) 243–269 73.0–504 Counts:

Diagnosis. A species of Platycephalus with the following combination of characters: second dorsal- and analfin rays usually 14; caudal-fin rays 12–13; pored lateral-line scales 70–81; gill rakers 1–2 + 6–9 = 7–11; orbital diameter 16.9–22.6% HL; interorbital width 7.4–14.1% HL; postorbital length 49.7–56.2% HL; suborbital width 5.4–9.7% HL; occipital and lower half of suborbital regions scaled; margin of interopercle smooth; one or two large caniniform teeth present anteromedially on upper jaw; all or most pored lateral-line scales with one pair of sensory ducts and exterior openings posteriorly; swimbladder present; abdominal cavity dark brown or black.

Description. Counts and measurements shown in Table 8 .

Snout, interorbit, and occipital and lower half of suborbital regions scaled; area anteroventral to eye naked. Interorbit narrower than orbital diameter. Upper iris lappet simple, weakly pointed; lower absent. Nasal, preorbital and supplemental preopercular spines absent. One suborbital spine present below and slightly posterior to posterior margin of eye in 337 mm SL or smaller specimens, absent in larger specimens; one additional spine also present below middle of eye on right side of 191 mm SL specimen. Lower preopercular spine longer than upper, not reaching opercular margin; some specimens with lower spine more than twice length of upper. Interopercular flap absent; margin of interopercle smooth. Maxilla not usually reaching anterior margin of pupil or beyond, although it may reach to middle of eye in some specimens. Upper jaw with one or two large caniniform teeth anteromedially. Palatine teeth in two rows, villiform or small conical in outer row, large conical to large caniniform in inner row. Vomerine teeth in one or two rows. Fleshy sensory tubes from suborbitals and preopercle not covering cheek region. Posterior tip of pelvic fin reaching origin of anal fin to base of third anal-fin ray. Posterior margin of caudal fin slightly concave. Swimbladder present.

Color in alcohol. Ground color of head and body pale brown above, paler below. Side of body with single row of purplish gray spots. First and second dorsal fins with indistinct pale brown spots. Pectoral and pelvic fins pale brown, with or without indistinct brownish bands; lower margin of fins paler. Anal fin with melanophores along rays. Caudal fin usually dusky; NMV A9033 with brown spots anteriorly, brown bands posteriorly. Abdominal cavity dark brown or black.

Distribution. Known from southern Australia, from Lakes Entrance, Vic (147°59’E) to Geraldton, WA (ca. 29°21’S), including SA, on continental shelf and upper slopes in depths from 53 to 530 m (e.g., May & Maxwell, 1986; Hoese et al., 2006; Gomon, 2008; this study).

Size. Maximum length 70 cm SL ( Gomon, 2008). The largest specimen examined during the present study was 607 mm SL (701 mm TL).

Remarks. Platycephalus conatus most resembles P. richardsoni in having the lower half of the suborbital region scaled, a swimbladder present and the abdominal cavity dark brown or black; this combination of characters does not occur in other species of Platycephalus . Platycephalus conatus can be separated from P. richardsoni in having 7–11 total gill rakers (vs. 12–17 in P. richardsoni ), and all or most pored lateral-line scales with one pair of sensory ducts and exterior openings posteriorly (vs. usually two pairs of sensory ducts and exterior openings).

Figures

FIGURE 22. (A) Dorsal and (B) lateral views of Platycephalus conatus, CSIRO H 4133 - 04, 550 mm SL, Great Australian Bight, WA.

Tables

TABLE 8. Comparison of counts and proportional measurements of Platycephalus conatus.

D1	I + VII–VIII + 0	I + VII–VIII + 0–I
		(usually I + VIII + 0)
D2	14	14–15 (usually 14)
A	14	14
P1	2 + 13 + 6 = 21	2–3 + 11–13 + 5–8 = 20–21
C	13	12–13 (usually 13)
LLS (spines)	70–79 (2)	72–81 (2)
OBS	77–82	77–84
GR	1 + 7 = 8	1–2 + 6–9 = 7–11
As % SL:
HL	35.0–35.5	33.9–37.9
PDL	36.7–37.3	36.1–39.5
LD1B	18.9–20.6	17.2–21.9
LD2B	31.0–31.1	29.1–32.3
LAB	32.9–33.3	30.5–36.3
SNL	9.7–10.1	9.5–11.2
OD	7.4–7.5	5.9–8.2
UJL	13.2–13.3	12.5–14.4
LJL	17.3–18.0	16.8–19.5
IW	3.3–3.5	2.7–4.9
POL	18.0–18.5	17.8–20.4
SW	2.1–2.2	1.9–3.5
P1L	15.4–15.5	14.1–15.7
P2L	25.5–25.8	20.2–27.9
CL	16.5–16.9	16.3–19.3
As % HL:
SNL	27.7–28.5	27.3–29.5
OD	21.0–21.2	16.9–22.6
UJL	37.4–37.6	35.6–38.0
LJL	49.4–50.6	48.6–51.4
IW	9.3–10.0	7.4–14.1
POL	50.5–52.7	49.7–56.2
SW	6.0–6.3	5.4–9.7