Sebastes ventricosus Temminck & Schlegel, 1843

Su, Yo, Yang, Tsung-Yu & Lin, Chien-Hsiang, 2025, A southward range extension of the rockfish, Sebastes ventricosus (Scorpaeniformes: Scorpaenidae: Sebastinae) to Matsu Islands, Taiwan, Zootaxa 5588 (3), pp. 465-475 : 466-472

Sebastes ventricosus Temminck & Schlegel, 1843

New Chinese name: ƋÀỸae/圓MỸae

Figures 1–5 ; Tables 1 , 2

Sebastes ventricosus Temminck & Schlegel, 1843: 48 , Pl. 20, figs. 1–2, type locality: Nagasaki, Japan (lectotype: RMNH D575, paralectotypes: RMNH D572–D574; ZMB 777, 779, 8164); Kai & Nakabo 2008: 251 (in part, redescription, Japan and Korea); Matsunuma et al. 2010:82 (in part, Kagoshima Prefecture, Japan); Nakabo & Kai in Nakabo 2013: 677 (in key, Japan); Kim et al. 2020: 93 (in part, Korea); Sonoyama et al. 2020: 43 (in part, Yamaguchi Prefecture, Japan); Yasutake et al. 2021: 36 (in part, AFLP and morphological analyses, northern Kyushu, Japan).

Specimen examined. NMMB-P 41104, 158.8 mm SL, off Beigan , Matsu Islands (ca. 26°13'6.51"N, 120°0'39.81"E), Taiwan, 12 January 2024, hook and line, collected by K.-C. Lin and J.-F. Hsiao.

Otolith: CHLOL 30253, 7.6 mm otolith length.

Other material: sagittal otoliths of Sebastes ventricosus : CHLOL 29758 , 178.0 mm SL, 7.7 mm otolith length and CHLOL 29761 , 164.0 mm SL, 8.6 mm otolith length, Osaka, Japan, 9 May 2024, collected by C.-H. Lin.

Description. Meristic and morphometric data are provided in Tables 1 and 2 . Paired fins and lateral-line scales are presented as left/right whenever available.

Dorsal-fin rays XIII, 14; pectoral-fin rays 16/16, with lower 7/7 rays unbranched; pelvic-fin rays I, 5; anal-fin rays III, 7; principal caudal-fin rays 8+7; procurrent caudal-fin rays 10 on both upper and lower lobes. Gill rakers on outer face of first gill arch 11+1+25=37; pseudobranchial filaments 37. Lateral-line scales 43/45, not including 2/2 scales on caudal-fin base. Vertebrae 11+15=26. Branchiostegal rays 7.

Body oblong, body depths 1 and 2 3.1 and 2.9 in SL, respectively. Head moderately large, its length 2.9 in SL, its height slightly smaller than its length; nape rounded; eyes large, 3.0 in HL; space between eyes slightly convex, interorbital width 3.8 in HL; snout length 4.8 in HL.

Mouth moderately oblique, upper-jaw length 2.4 in HL; posterior end of maxilla reaching vertical through middle of eye. Posterior nostril oval, distinctly larger and situated higher than anterior one; anterior nostril rounded, positioned at level of horizontal line passing through middle of eye. Premaxilla and dentary with villiform teeth at mesial face; their lateral surface covered by skin. Villiform teeth present on vomer and palatine.

Gill rakers on outer row of first arch rod-shaped and laterally compressed, with small conical teeth on inner surfaces; gill rakers on second to third arches shorter than the ones on first arch; gill rakers on inner row of first to third arches forming bumps. Gill filaments present on all four arches. No slit between fourth arch and fifth ceratobranchial.

Body covered with ctenoid scales, including head, operculum, snout, lateral surfaces of maxilla and lower jaw, lachrymal bone, abdomen, and dorsal, anal, and caudal-fin bases. Lateral-line scales same size as adjacent scales on body, their midline forming a ridge; origin of lateral line above supracleithral spine, running nearly straight anteriorly, slightly downturned above anus, and straight again on posterior portion of body; its posterior end extending onto caudal-fin base.

Nasal, preocular, supraocular, parietal, and supracleithral spines present and simple. Preopercle with five simple spines; second spine longest, remaining ones gradually decreasing in size to last spine; all spines protruding from skin. Opercle with two spines; upper spine longer than lower spine and directed posterodorsally; lower spine directed posteroventrally; both spines reaching slightly beyond posterior margin of opercular membrane. Lacrimal bone with two simple spines; both spines subequal in length and directed posteroventrally ( Fig. 3 ).

Dorsal-fin spines progressively longer from first to sixth spine, and gradually shorter posteriorly, with distinct notch at level of penultimate spine; all soft rays branched; last ray divided at base and connected to body by membrane; outer margin of soft-ray portion slightly rounded. Pectoral-fin length 3.3 in SL, its posterior margin not reaching to anal-fin origin. Pelvic fin length 4.0 in SL, its tip at same vertical through posterior margin of pectoral fin. Anal-fin spines progressively longer posteriorly; outer margin of soft-ray portion slightly pointed; 2 nd and 3 rd soft anal-fin rays longest. Posterior margin of caudal fin convex, slightly notched in the middle. Caudal-peduncle depth 3.0 in HL.

Coloration

When defrosted ( Fig. 1 ), dorsum above lateral line blackish; lower parts of body paler; flanks silvery with dark pigment extending below lateral line at level of spinous and posterior portion of soft dorsal fin; abdomen white. Top of head, snout and lower-jaw tip dark brown; sides of head, including operculum silvery brown; maxilla silvery with submarginal dark band ventrally. Pectoral fins blackish with oblong pale patch on basal part. All other fins somewhat paler, with spinous dorsal fin darker than rest. Pelvic fins with dark pigment concentrated basally and distally.

When preserved ( Fig. 2 ), head and body overall tan, slightly paler ventrally. Distal margins of dorsal, pelvic, and anal fins dark. Oral cavity, including underside of tongue, gill rakers and gill arches pale. Inner face of operculum dusky.

Osteology ( Fig. 4 )

Neural spines present on all precaudal vertebrae; parapophysis developed on seventh to 11 th vertebra; pleural ribs present on third to 11 th vertebra; epineurals present on second to tenth vertebra; epipleurals absent. Dorsal-fin supraneural and pterygiophore insertion formula: S//2+1/1/1/1/1/1/1/1/1/1/1 (fin spines only). First anal-fin proximal pterygiophore inserts between 11 th and 12 th vertebra.

Sagittal otolith ( Fig. 5 )

Otoliths fusiform, with pointed rostrum. Dorsal and posterior rims crenulate or irregular; ventral rim smoothly curved. Inner face convex, outer face slightly concave, moderately thickset. Sulcus well-delineated and well-divided. Ostium oblong, filled with low colliculum. Cauda elongated, rod-like, slightly ventrally directed posteriorly. Collum markedly constricted, especially on crista superior. Large dorsal depression above crista superior.

Distribution ( Fig. 6 )

Previously known from the southern Korean Peninsula and Japan at a latitude above 32° N ( Kai & Nakabo 2008; Nakabo & Kai 2013; Sonoyama et al. 2020). Our specimen represents the southernmost (ca. 26° N) record of this species and the first record from Taiwan’s EEZ.

Figures

FIGURE 1. Defrosted specimen of Sebastes ventricosus Temminck & Schlegel, 1843, NMMB-P 41104, 158.8 mm SL. Upper: on gray background and lower: on black background.

FIGURE 2. Preserved specimen of Sebastes ventricosus Temminck & Schlegel, 1843, NMMB-P 41104, 158.8 mm SL, photo by Y.-C. Hsu.

FIGURE 3. Head region of Sebastes ventricosus Temminck & Schlegel, 1843, NMMB-P 41104, 158.8 mm SL. Abbreviations: AN, anterior nostril; LAC, lachrymal spines; NA, nasal spine; OP, opercular spines; PA, parietal spine; PN, posterior nostril; PO, preocular spine; POP, preopercular spines; SCL, supracliethrum spine; and SO, supraocular spine. Anterior to left. Figure not to scale.

FIGURE 4. X-radiograph of Sebastes ventricosus Temminck & Schlegel, 1843, NMMB-P 41104, 158.8 mm SL.

FIGURE 5. Sagittal otoliths (inner views) of Sebastes ventricosus Temminck & Schlegel, 1843. A. CHLOL 30253, 7.6 mm otolith length, Taiwan. B. CHLOL 29758, 7.7 mm otolith length, Japan. C. CHLOL 29761, 8.6 mm otolith length, Japan. Scale bar = 1 mm.

FIGURE 6. Distribution map of Sebastes ventricosus Temminck & Schlegel, 1843. Only records with precise locality are included. Star=present study; circle=other records.

Tables

TABLE 1. Meristic characters of Sebastes ventricosus Temminck & Schlegel, 1843. Data of other specimens were retrieved from Kai & Nakabo (2008). Paired characters are presented as left/right whenever available.

	This study	Kai & Nakabo (2008)
	NMMB-P 41104	n=54
Dorsal-fin rays	XIII, 14	XIII, 14–16
Pectoral-fin rays	16/16	15–17
Pelvic-fin rays	I, 5	I, 5
Anal-fin rays	III, 7	III, 7–8
Gill rakers	11+1+25=37	35–39
Lateral-line scales	43+2/45+2	43–49
Vertebrae	11+15=26	11+15=26