Samaris spinea Mihara and Amaoka, 2004

Tütüncü, Havva Esra, Durmuş, Naciye & Sürmeli, Yusuf, 2023, A Rare Flatfish, Samaris spinea (Teleostei: Pleuronectiformes: Samaridae) from the Ogasawara Islands, Japan, with Notes on Its Distribution, Taxonomy and Sexual Dimorphism, Bulletin of the National Museum of Nature and Science. Series A, Zoology 49 (4), pp. 179-189 : 180-184

Samaris spinea Mihara and Amaoka, 2004

[Standard Japanese name: Toge-hatatate-garei]

( Figs. 2–4 ; Table 1 )

Samaris spinea Mihara and Amaoka, 2004: 624 , figs. 8–13, 20; Amaoka et al., 2004: 2, figs. 1–3; Fricke and Kulbicki, 2006: 355; Voronina and Suzumoto, 2017: 7, fig. 6; Voronina and Volkova, 2019: 274 , fig. 24.

Samaris spineus : Nakabo and Doiuchi, 2013: 1685; Nakabo and Hirashima, 2015: 266; Amaoka, 2016: 203, fig. 6.

Specimen examined. NSMT-P 109872 , 32.9 mm SL, male, off northwest coast of Ototo-jima Island , Ogasawara Islands, Tokyo Prefecture, Japan, 27°13′05″N 142°09′11″E to 27°13′11″N 142°09′13″E, 135.8– 135.5 m depth, 15 July 2009, 50 cm ORI dredge, R / V Koyo-maru .

Diagnosis. Samaris spinea is separable from the other species of Samaris by the following combination of characters: dorsal-fin rays 60–72; prolonged dorsal-fin rays 3–7; anal-fin rays 46–54; lateral line scales 44–58; vertebrae 9–10 +27–31; body depth 36.0–41.5% SL; caudal-fin rays bifurcated except uppermost and lowermost two simple rays; 2–6 spines along dorsal and ventral margins of caudal peduncle on ocular side ( Amaoka et al., 2004; Mihara and Amaoka, 2004; present study).

Description. Proportional measurements (% SL) and counts are provided in Table 1 .

Head length 4.0 in SL on ocular side, 3.8 on blind side; body depth 2.6 in SL; snout length 4.0 in HL; upper eye diameter 3.2 in HL; lower eye diameter 3.0 in HL; interorbital width 23.6 in HL; upper jaw length 3.0 in HL on ocular side, 3.6 on blind side; lower jaw length 1.9 in HL on ocular side, 2.2 on blind side; caudal peduncle length 17.0 in SL; caudal peduncle depth 8.3 in SL; pectoral-fin length 3.5 in SL on ocular side; pelvic-fin length 4.8 in SL on ocular side, 7.1 on blind side; pelvic-base length 13.2 in SL on ocular side, 20.2 on blind side; middle caudal-fin ray length 3.5 in SL; length of anterior prolonged dorsal-fin ray 4.0 in SL.

Body laterally compressed, elliptical, deepest at midpoint ( Fig. 2 ). Head small, the dorsal profile slightly sloping anteriorly; head on ocular side slightly smaller than that on blind side. Eyes dextral, of moderate size, separated by scaleless narrow bony ridge; both eyes naked except for lower part of upper eye with one weak ctenoid scale; anterior margins of upper and lower eyes nearly on same vertical line. Nostrils on ocular side two, situated anterior to interorbital space; both nostrils on ocular side with long nasal tube, anterior tips reaching upper jaw when bent antero-ventrally; nostrils absent on blind side. Pores of supraorbital canal on ocular side two; pores of supraorbital canal on blind side absent. Mouth oblique; anterior tip of premaxilla just in front of upper margin of lower orbit; maxilla extending below anterior margin of lower eye, not reaching below middle of lower eye; lower jaw slightly protruded; teeth small, in bands on both jaws. Vomer and palatine toothless. Gill rakers on first arch rudimentary on both limbs, but more developed on lower limb. Gill membranes united to each other. Scales ctenoid on head and body on ocular side, cycloid on head on blind side, cycloid and weakly ctenoid on anterior 1/3 part of body on blind side, weakly ctenoid on posterior 2/3 part of body on blind side; strongly ctenoid on dorsal-, anal-, caudal- and pelvic-fin bases of both sides; scales absent on snout, interorbital region, most parts of eyes, upper jaw, and dorsal, anal, pectoral and pelvic fins, and posterior 2/3 of caudal fin. Lateral line on ocular side nearly straight; lateral line absent on blind side.

Small spines present along dorsal and ventral margins of caudal peduncle; five on dorsal margin with fourth longest and fifth shortest, first, second and fourth simple, third and fifth bifurcated; six on ventral margin with fifth longest and first shortest, first, second, third and fifth simple, fourth and sixth bifurcated ( Figs. 3 , 4 ).

Dorsal-fin origin anterior to upper orbit; dorsal-fin membrane originating just behind anterior part of upper jaw on blind side; first three dorsal-fin rays prolonged, with first and second rays longer than third. Anal-fin origin slightly posterior to anus. Pectoral-fin rays on ocular side short, not reaching middle of body; pectoral fin absent on blind side. Pelvic-fin rays on ocular side prolonged, third ray greatly prolonged, first and second rays broken; pelvic-fin rays on blind side short; pelvic-fin base on ocular side longer than base on blind side; pelvic-fin origin on ocular side slightly ahead of origin on blind side. All dorsal-, anal-, pectoral- and pelvic-fin rays simple. Caudal fin elongated and rounded; all caudal-fin rays bifurcated except uppermost and lowermost two simple rays; middle rays longest. Anus on midventral line between pelvic and anal fins. Urogenital papilla positioned on ocular side adjacent to anus.

Epicentra present on lateral sides of second to sixth abdominal vertebrae; absent on caudal vertebrae ( Figs. 3 , 5 ). Epimerals absent. Hypomerals present on ventral sides of fourth abdominal vertebrae to fourth (ocular side) or sixth (blind side) caudal vertebrae; absent on posterior caudal vertebrae.

Color in alcohol ( Fig. 2 ). Ocular side of body whitish brown; two brown blotches just below lateral line behind pectoral fin; three to four small brown blotches on dorsal and ventral margins of body; large brown blotch on posterior-most parts of dorsal- and anal-fin bases. Blind side of body whitish brown without spots or dots. Dorsal- and anal-fin membranes with five brown blotches and many small brown dots basally. Caudal fin with brown blotch basally, large brown blotch centrally, and small brown dots distally. Pectoral-fin membrane uniformly brown; pelvic-fin membrane uniformly whitish and transparent.

Distribution. Known from New Caledonia, and Ryukyu Islands (off Kerama Islands) and Ogasawara Islands, Japan at depths of 44–135.5 m ( Amaoka et al., 2004; Mihara and Amaoka, 2004; present study; Fig. 1 ).

Figures

Fig. 2. Lateral view of ocular (A) and blind (B) sides of Samaris spinea, NSMT-P 109872, 32.9mm SL, Ogasawara Islands, Japan.

Fig. 3. CT images of osteology on ocular (A) and blind (B) sides of Samaris spinea, NSMT-P 109872, 32.9mm SL.

Fig. 4. CT images of transformed scales with small spines along dorsal (A) and ventral (B) margins of caudal peduncle on ocular side of Samaris spinea, NSMT-P 109872, 32.9mm SL.

Fig. 5. CT images of osteology of head and anterior body on ocular side in Samaris spinea, NSMT-P 109872, 32.9mm SL. EC: epicentrum; HM: hypomeral.

Fig. 1. Map showing collection localities for specimens of Samaris spinea reported. Star, diamond and triangles: records for the present specimen, and those in Amaoka et al. (2004) and Mihara and Amaoka (2004), respec- tively.