Robaloscion wieneri ( Sauvage, 1883 ) Béarez & Schwarzhans, 2013

Béarez, Philippe & Schwarzhans, Werner, 2013, Robaloscion, a new genus for Sciaena wieneri Sauvage, 1883 (Teleostei, Sciaenidae) from the southeastern Pacific, with clarification of the taxonomic status of Sciaena starksi Evermann & Radcliffe, 1917, Cybium 37 (4), pp. 273-279 : 276-277

Robaloscion wieneri ( Sauvage, 1883) new combination

( Figs 2 , 3 )

Diagnosis Same as for genus.

Description

Morphometric and meristic data are presented in table I. Body elongate, moderately compressed, sub-cylindrical in transverse section. Maximum depth 3.5 to 4.2 in SL. Dorsal profile straight to slightly convex over the head. Head rather long, 3.2 to 3.4 in SL, and fairly low. Snout long, 3.4 to 4.1 in HL. Eye small, orbit diameter contained 6.4 (in young specimens) to 13.4 (in large adults) times in HL. Mouth terminal, slightly oblique. Maxillary reaching to or beyond posterior margin of eye. Upper jaw with one external row of small conical teeth, slightly curved towards the interior of the mouth, and one internal band of villiform teeth (ca. 5 rows). Lower jaw with one internal row of small conical teeth, slightly curved towards the interior of the mouth, and one small external band of villiform teeth (ca. 2 rows). Gill rakers moderately developed, median ones distinctly shorter than gill filaments at angle of first gill arch, and becoming coarse with size - 8 to 10 on lower limb of first arch, total number on first arch 8-14. Preopercle with weak and broad indentations at margin, generally covered by skin and soft to touch.

Dorsal fin with 11(X+I) weak spines and 21-24 soft rays, third or fourth spine the longest. Anal fin short with 2 weak spines and 10 soft rays. Pectoral fin short, with 19 rays, not reaching tip of pelvic fin; 1.9 to 2.2 times in HL. Pelvic fin about the same length, 1.9 to 2.3 times in HL, its origin clearly behind that of pectoral fin. Caudal fin emarginate to lunate, with lobes of about equal length.

Body covered with ctenoid scales. Lateral line very slightly arched anteriorly with 75-78 pored scales to end of hypural plate, but extending to tip of caudal fin. Pored lateral-line scales with branching lateral-line canals and intercalated with smaller scales. Nine to ten lateral rows of scales between lateral line and base of first dorsal spine. Twelve to thirteen rows of scales between lateral line and base of first anal spine.

Vertebral count 25 (11+14). Gas bladder carrot-shaped with an elongated posterior end, and a pair of stout and short, horn-like appendages at antero-lateral corners of main chamber, projecting anteriorly.

Description of sagitta otolith

Robaloscion wieneri probably possesses one of the biggest and most massive sagittae in the Sciaenidae . The sagitta is the only well developed otolith in this species ( Fig. 1 C-J); it is very elongate (l:h = 2.6-2.7) and massive (h:t = 0.7-0.8). Dorsal and ventral rims almost straight and nearly parallel; dorsal rim occasionally with slight mid-dorsal expansion in smaller otoliths; ventral rim slightly concave in middle section in larger otoliths. Anterior tip rounded, somewhat dorsally pronounced; posterior tip more quadrate, vertical or with weak ventral projection. Inner face convex with an curvature index (l:z) of 5.5. Sulcus typically hetero-sulcoid, tadpole-shaped, spread over most of inner surface. Ostium very long, covering the anterior half of sagitta, somewhat depressed dorsally; ol:oh = 1.8-2.0, cl:ol = 0.9-1.1. Postostial lobe well developed, precaudal depression present, caudal joint oblique. Cauda very deep, with proximal part long and straight, parallel and close to dorsal edge; distal portion somewhat widened and curved downward at nearly 90°, marked by a sharp angle of its ventral margin. Index of horizontal part of cauda to downward curved part (x:y) 1.2-1.4. Outer face with massive central to post-centrally expanding umbo, made up of stalactite-like, spongy, concreationary aggregates that fuse together with growth. Posterior tip of otolith thicker than the anterior tip.

Figures

Figure 1. - Drawings of Robaloscion wieneri right sagittae. A, B: Schematic drawing of right sagitta, with measurements used for proportional ratios (see text for abbreviations, modified from Schwarzhans (1993). C: Medial view of # 5153. D-G: Medial, anterior, ventral, and posterior views of # 5057. H, I: Medial and ventral views of # 5166. J: Medial view of # 5030. Drawings by W. Schwarzhans.

Figure 2. - Holotypes. A: Sciaena wieneri Sauvage,1883, MNHNA-4852, 456 mm SL. B: Sciaena starksi Ever- mann & Radcliffe, 1917, USNM 53464, 382 mm SL.

Figure 3. - Fresh specimen of Roba- loscion wieneri, MNHN 2001-1365, 308 mm SL. Photograph by P. Béarez.