Stolephorus grandis Hata & Motomura 2021

Stolephorus grandis Hata & Motomura, 2021b [English name: Papuan Double-lined Anchovy] Figure 2; Tables 1, 2 Stolephorus grandis Hata & Motomura, 2021b: 481, fig. 1 [type locality: Merauke, Papua, Indonesia; paratype localities: Cairns, Queensland and Van Diemen Gulf, Northern Territory, Australia] Materials examined. 18 specimens, 59.2–116.1 mm SL. Holotype. RMNH.PISC. 24670, 102.9 mm SL, Merauke, Papua, Indonesia, 5 Apr. 1955. Paratypes. 9 specimens, 59.2–116.1 mm SL: AMS-I. 22777-006, 59.2 mm SL, south end of Ellis Beach, north of Queensland, Cairns, Australia (16°43′48″S, 145°39′00″E); RMNH.PISC. 84311, 116.1 mm SL, collected with the holotype; KAUM–I. 156158, 82.6 mm SL, NSMT-P 140585, 80.5 mm SL, NTM S. 10071-001, 5 specimens, 77.7–88.0 mm SL, Van Diemen Gulf, Northern Territory, Australia. ......continued on the next page ......continued on the next page Abbreviations: D–P1 (distance between dorsal-fin origin and pectoral-fin insertion); D–P2 (distance between dorsalfin origin and pelvic-fin insertion); D–A (distance between origins of dorsal and anal fins); P1–P2 (distance between insertions of pectoral and pelvic fins); P2–A (distance between pelvic-fin insertion and anal-fin origin). Nontype specimens. INDONESIA: NCIP 3751, 107.0 mm SL, eastern Indonesia; TU 170854, 2 specimens, 77.4–89.3 mm SL, 4 km off estuary of Ajikwa River, Mimika Regency, Central Papua; TU 178597, 84.1 mm SL, estuary of Minajerwi River, Mimika Regency, Central Papua. PAPUA NEW GUINEA: CSIRO H 8834-01 (tissue code: BW-A16956, BOLD accession number: FOAQ794-22), 106.1 mm SL, Gulf of Papua, east of Fly River mouth (08°34′S, 144°10′E), 12–17 m depth; CSIRO H 8838-01, 113.5 mm SL, off Purari, Gulf of Papua (07°54′S, 145°00′E), 13–14 m depth. AUSTRALIA: QM I.16538, 1 of 2 specimens, 95.5 mm SL, beach at Squatters Hut, Murray River, Queensland (18°05′S, 146°00′E); QM I.27596, 1 of 10 specimens, 93.0 mm SL, Karumba Point Beach, near Norman River mouth, Queensland (17°27′S, 140°50′E), 0–1.5 m depth. Materials for distributional records (morphometric and meristic data not collected; 3 specimens: 58–60 mm SL). CSIRO A 1207, 60 mm SL, CSIRO A 1234, 58 mm SL, CSIRO A 1235, 59 mm SL, Repulse Bay, mouth of Proserpine River, Queensland, Australia (20°28′S, 148°42′E). Diagnosis. A species of Stolephorus with the following combination of characters: 1UGR 14–17 (modally 16), 1LGR 21–23 (22), 1TGR 35–39 (39); 2UGR 10–12 (11), 2LGR 18–21 (20), 2TGR 28–33 (31); 3UGR 8–10 (9), 3LGR 10–12 (11), 3TGR 18–22 (20); 4UGR 7–9 (8), 4LGR 9–10 (9), 4TGR 16–19 (17); prepelvic scutes 3–6 (4, 5); scale rows in longitudinal series 35–38 (36); transverse scales 8; pseudobranchial filaments 20–27 (24); vertebrae 42–43 (42); paired dark patches on parietal and occipital regions; paired dark lines on left and right on dorsum from occipital region to dorsal-fin origin but absent behind dorsal-fin base; no black spots on suborbital area and tip of lower jaw; predorsal scute absent; no spine on pelvic scute; posterior margin of preopercle rounded, not indented; maxilla comparatively short, 16.7–18.3% of SL (mean 17.7%), its posterior tip slightly short of or slightly beyond posterior margin of preopercle; lower jaw comparatively short, 14.3–15.3% of SL (14.8%); head comparatively short, 22.0–24.0% of SL (23.1%); postorbital length comparatively short, 11.5–12.4% of SL (12.0%); short dorsal-fin base, 12.6–14.8% of SL (14.0%); short anal-fin base, 16.0–17.8% of SL (16.9%); caudal peduncle long, 21.9– 23.7% of SL (22.8%); pelvic fin short, 8.3–9.0% of SL (8.6%), posteriorly not reaching to vertical through dorsal-fin origin when depressed; anal-fin origin located below ninth to twelfth dorsal-fin ray origin; no melanophores on pectoral fin. Description. Body elongated, subcylindrical, deepest at dorsal-fin origin. Dorsal profile gently elevated from snout tip to dorsal-fin origin, thereafter, gradually decreasing to dorsal contour of central part of caudal peduncle. Ventral profile gently descending from tip of lower jaw to insertion of pelvic fin, thereafter nearly straight (parallel to body axis) to origin of anal fin, subsequently ascending along anal-fin base. Ventral contour of caudal peduncle nearly straight and parallel to body axis. Abdomen rounded, covered with three to six prepelvic scutes. Prepelvic scutes spine-like, retrorse, hard. No scutes on abdomen posterior to pelvic scute. No spine on pelvic scute. Predorsal scute absent. Snout projecting, rounded, positioned lower than upper margin of eye. Orbit elliptical, entirely covered with eyelid. Eye longer than snout, positioned above pectoral-fin insertion. Iris round. Interorbital space flat, narrower than eye diameter. Nostrils paired, positioned close to each other, just anterior to orbit. Mouth large, inferior, almost parallel to body axis, extending backward to posterior margin of orbit. Maxilla rather long, extending posteriorly almost to or slightly beyond posterior margin of preopercle. Lower jaw slender. Mandibular joint located posterior to posterior margin of eye. Uniserial small conical teeth on both jaws. Single (partly biserial) rows of conical teeth on palatines. Several conical teeth present on vomer. Teeth patch formed by fine, densely packed teeth present on pterygoids. Several rows of conical teeth on upper edges of basihyal. Dorsal surface of hyoid arch entirely smooth, but small rough teeth present in parts. Posterior margins of preopercle, subopercle, and opercle rounded (not indented), smooth, without serrations. Pseudobranchial filaments present on inner side of opercle and exposed, not covered with skin (visible without dissection); length of longest filament less than eye diameter. Gill arch four pairs, gill rakers present on anterior surfaces of all gill arches and posterior surface of third gill arch. Gill rakers slender, rough, visible from side of head when mouth open. Gill filaments present on all gill arches. Isthmus muscle long, anteriorly reaching to posterior margin of gill membranes. Urohyal embedded in isthmus muscle, not visible without dissection. Gill membranes on both sides joined distally, most of isthmus muscle exposed (not covered by gill membrane). Branchiostegal rays elongated, entirely covered with gill membrane. Anus situated just before anal-fin origin. Pectoral fin triangular, posterior tip pointed, dorsal, posterior, and ventral margins almost straight; fin insertion slightly posterior to posterior margin of opercle, lower than snout tip; posterior tip not reaching to pelvic-fin insertion; uppermost ray unbranched, others branched. Pelvic fin almost triangular, outer contours almost straight; posterior tip of depressed fin not reaching to vertical through dorsal-fin origin; anteriormost fin ray unbranched, others branched. Dorsal fin nearly triangular, anterior and dorsal profile nearly straight; fin origin located slightly anterior to middle of body; anterior three fin rays unbranched, others branched; first ray tiny. Anal-fin origin located just below 9th to 12th dorsal-fin ray origin; anterior three fin rays unbranched, others branched; first ray tiny; posterior tip of depressed fin not reaching to caudal-fin base. Caudal fin forked, posterior tips of both lobes pointed; anterior and posterior margins of both lobes nearly straight. Head without scales. Fins scaleless, except for broad triangular sheath of scales on caudal fin and elongated sheath of scales on bases of dorsal and anal fins. Body scales completely lost, except for prepelvic scutes. Coloration of fresh specimens. Based on CSIRO H 8834-01 and CSIRO H 8838-01 frozen for six years before photography (Fig. 2A, B). Body milky-white, silver longitudinal band (width subequal or narrower than eye diameter) running through middle part of body from cleithrum to caudal-fin base. Silver band with narrow black margin dorsally. Cheek, opercle, and pectoral-fin axillary scale silver. Snout, maxilla, and pelvic-fin axillary scale transparent. Melanophores densely scattered on snout tip, dorsal margin of gill opening, anal-fin base, middle of caudal-fin base, and dorsal surface of caudal peduncle. Pairs of dark patches on parietal and occipital regions. Paired dark lines on dorsum anterior to dorsal fin, but not posterior to dorsal fin. Posterior margins of scale pockets above silver longitudinal line black. Melanophores scattered along fin rays of dorsal and caudal fins. No melanophores on anterior part of lower margin of caudal fin. Pectoral, pelvic, and anal fins translucent, without melanophores. Iris silver, pupil black. Coloration of preserved specimens. Body uniformly pale, longitudinal band brownish (sometimes remaining silver) and dorsal margin black. Melanophores scattered on lateral surface of head (upper margin of gill opening and snout tip). Pairs of dark patches on parietal and occipital regions. Paired dark lines on dorsum anterior to dorsal fin, but not posterior to dorsal fin. No melanophores on suborbital area. Melanophores scattered along fin rays of dorsal and caudal fins. No melanophores on pectoral, pelvic, and anal fins, and anterior part of lower margin of caudal fin. Scale pockets on dorsum with black margins. Distribution. Stolephorus grandis is distributed along the south coast of New Guinea and north coast of Australia (from Van Diemen Gulf, Northern Territory to Repulse Bay, Queensland) (Hata & Motomura 2021b; this study: Fig. 3). Remarks. Stolephorus grandis was described by Hata & Motomura (2021b) based on ten specimens collected from only three localities, Merauke (New Guinea), Cairns (Queensland), and Van Diemen Gulf (Northern Territory). Eleven additional specimens confirmed in this study suggest that the species may be distributed along the entire southern coast of New Guinea and northern coast of Australia (Fig. 3). Hata & Motomura (2021b) compared S. grandis with three species with double black lines on dorsum, long maxilla with posterior tip just reaching or reaching slight