Lophiomus laticeps (Ogilby, 1910) stat. rev.

urn:lsid:zoobank.org:act: 4226D3F2-F927-4460-A63D-DABBDDA14E34

Figs 10–11, 15B, 16A–B; Tables 3–6

Chirolophius laticeps Ogilby, 1910: 136.

Lophiomus setigerus (not Vahl, 1797) – Caruso 1983: 13 (in part).

Diagnosis

This species can be separated from other congeners by the combination of dorsal-fin spines 6, pectoral-fin rays 24–25, pelvic-fin rays 7, pale khaki body coloration, and light floor of mouth having anastomosing dark pattern medially.

Differential diagnosis

Lophiomus laticeps resembles Lm. nigriventris sp. nov. according to their shared pale khaki body coloration. However, notable distinctions include higher counts of pectoral-fin rays (24–25 vs 23–24, mostly 23 in Lm. nigriventris sp. nov.; Table 6) and pelvic-fin rays (7 vs 6 in Lm. nigriventris), longer DS2 (17.4–25.5% SL vs 17.9–20.7% SL in Lm. nigriventris) and DS3 (27.3–33.7% SL vs 18.9–24.0% SL in Lm. nigriventris), narrower ISP (39.2–39.9% HL vs 40.6–45.4% HL in Lm. nigriventris), tassel-like flap of esca (pennant-like in Lm. nigriventris), a peritoneum without dark or gray pigmentation (with dark pigmentation in Lm. nigriventris), and a light floor of the mouth having anastomosing dark pattern medially (light floor of the mouth with reticulate dark pattern in Lm. nigriventris).

This species is also different from the sympatric species Lm. carusoi sp. nov. in having higher counts of pectoral-fin rays (24–25 vs 23–24 in Lm. carusoi), a relatively longer (HL 34.2–39.9% SL vs 28.4–32.7% SL in Lm. carusoi) and a narrower head (HW 50.7–54.3% HL vs 58.1–68.6% HL in Lm. carusoi), a narrower ISP (39.2–39.9% HL vs 48.6–56.7% HL in Lm. carusoi), and shorter OPSOP (31.6–47.4% HL vs 55.5–65.7% HL in Lm. carusoi), a pale khaki body coloration (brown in Lm. carusoi), a peritoneum without dark or gray pigmentation (with dark pigmentation in Lm. carusoi), and a light floor of the mouth having an anastomosing dark pattern medially (light floor of the mouth with reticulate dark pattern in Lm. carusoi).

Lastly, this species is different from the type species Lm. setigerus in having higher counts of pectoral-fin rays (24–25 vs 21–23 in Lm. setigerus), pale khaki body coloration (brown in Lm. setigerus), peritoneum without dark pigmentation (with gray pigmentation in Lm. setigerus), and a light floor of the mouth having anastomosing dark pattern medially (dark floor of the mouth with circular or irregular light pattern in Lm. setigerus).

Material examined

Holotype

CORAL SEA • 145.1 mm SL (currently measured); West Pacific, Coral Sea, Moreton Bay, 58 km northeast off Cape Moreton; 27°10′ S, 153°17′ E; 133.5 m (73 fathoms) deep; 6 Jul.–13 Sep. 1910; F.I.S. “Endeavour”; trawl; Voucher: AMS E. 2973.

Non-type material

CORAL SEA • 237.1 mm SL, sample ID: NC1375; West Pacific, Coral Sea, SW of New Caledonia, north of Lord Howe seamount chain, Nova Bank, stn CP5004; 159°25′ E, 22°40′ S; 340 m deep; 18 Sep. 2017; R/V ALIS; French beam trawl; KANADEEP exped.; GenBank nos: OR261070 (COI), OR257541 (cytb), OR260587 (rhodopsin), OR257563 (RAG1); Voucher: NTUM13463 • 152.8 mm SL, sample ID: NC964; West Pacific, Coral Sea, SW of New Caledonia, North of Lord Howe seamount chain, Capel Bank, stn CP4930; 159°55’E, 25°08’S; 300 m deep; 3 Sep. 2017; R/V ALIS; French beam trawl; KANADEEP expedition; GenBank nos: OR261071 (COI), OR257542 (cytb), OR260586 (rhodopsin), OR257562 (RAG1); Voucher: NTUM13468.

Redescription

Adult

MEASUREMENTS AND MERISTIC COUNTS. Morphometric values given in Tables 3 and 4. Dorsal-fin spines 6; dorsal-fin rays 8, double-forked in last ray; anal-fin rays 6; pectoral-fin rays 23–25; pelvic-fin rays 7; branchiostegal rays 5; interopercular spines 2; vertebrae 18–19; outermost row of premaxillary teeth 15–22 (Tables 5–6).

HEAD AND BODY. Head relatively long (34.2%–39.9% of SL) and narrow (50.7%–54.3% of HL); eyes suboval; anterior half of premaxilla with three rows of enlarged teeth with largest on innermost row, followed by single row of small teeth on posterior half; maxilla toothless; palatine with single row of small teeth with some enlarged; dentary with three rows of teeth, outer teeth minute and innermost teeth largest; fifth ceratobranchial with two rows of small teeth, forming V-shaped patch; teeth on second and third pharyngobranchials forming small and rounded patches; gill rakers and pseudobranch absent. Palatine spines sharp, with posterior one stronger; frontal ridges and outer surface of maxilla, dentary bones bearing low and conical knobs; frontal spines blunt, with posterior one sharper; inner sphenotic spines low and blunt; outer sphenotic spines blunt, stronger than inner one; pterotic spines broad and blunt; parietal, epiotic, posttemporal spines short and blunt, inconspicuous; articular spines strong and sharp, with single spine anterior to jaw joint and projected forward; quadrate spines strong and sharp; hyomandibular spines blunt; opercular spines blunt; interopercular spines strong and sharp; subopercular spines blunt, with posterior one inconspicuous; cleithral spines strong and blunt; humeral spines well developed, with three to four sharp spinelets at tips; edge of head and caudal peduncle covered by pale tendrils.

FINS. Illicium moderate to long (23.3%–31.3% of SL), without tendrils; esca tassel-like flap with moderately long cirri and two dark, stalked, bulb-like appendages at base of esca in larger specimen; second dorsal-fin spine long (17.4%–25.5% of SL), stout, reaching between base of third dorsal-fin spine and epiotic spines, with dark tendrils; third dorsal-fin spine relatively long (27.3%–33.7% of SL), slender, reaching from about ¾ fourth dorsal-fin spine, without tendrils; fourth dorsal-fin spine slender, with sparse or without tendrils; fifth and sixth dorsal-fin spines short, mostly imbedded under skin and with dark tendrils; first dorsal-fin ray relatively close to second, both imbedded under skin, last two rays short; anterior three anal-fin rays imbedded under skin.

COLORATION (PRESERVED). Body color gray khaki, covered by sparse, circular dark marking (holotype only), dense, minute pale spots and blackish-brown irregular reticulate pattern on dorsal surface; ventral surface and peritoneum pale; floor of mouth light with anastomosing dark pattern in middle, obvious in larger specimen; dorsal surface of pectoral-fins dark apically, and pigmented as adjacent area of body basally; dorsal-fin pale; caudal fin dark basally and apically, with color pattern same as adjacent area of body.

COLORATION (FRESH). Body color pale khaki, covered by pale spots and blackish-brown irregular reticulate pattern on dorsal surface; dorsal surface of pectoral-fins brown with color pattern same as adjacent area of body basally; dorsal-fin and caudal fin pink covered by circular pale spots densely, brownish basally on caudal fin, with color pattern same as adjacent area of body.

Subadult

Unknown.

Distribution

Coral Sea, Moreton Bay at a depth of 133.5 m (holotype); Lord Howe seamount chain (Nova Bank and Capel Bank) at depths of 300 m and 340 m (two adult specimens) (this study, Fig. 1).

Remarks

The holotype of C. laticeps and two specimens collected from Lord Howe seamount chain are considered conspecific since their morphological similarities including pale khaki body coloration, 24 pectoral-fin rays, 7 pelvic-fin rays, and anastomosing dark pattern on the floor of the mouth (Figs 10–11; Table 5). As the holotype of C. laticeps was examined by Caruso, this species falls within the morphological variation of Lm. setigerus sensu Caruso (1983).

This species is partially sympatric with another Australian species, Lm. carusoi sp. nov. (Fig. 1). However, the distinction in morphology and genetics (Figs 2, 10–11, 14; Table 7), as well as their nonsister relationship (Figs 2–4), support the absence of a genetic flow between these two species.