Rhabdamia spilota Allen & Kuiter 1994

Yoshida, Tomohiro & Motomura, Hiroyuki, 2018, Redescription of the Indo-West Pacific cardinalfishes (Perciformes: Apogonidae) Rhabdamia spilota Allen & Kuiter 1994 and R. gracilis (Bleeker 1856), Zootaxa 4377 (2), pp. 178-190 : 179-185

Rhabdamia spilota Allen & Kuiter 1994

[English name: Glassy Cardinalfish; new Japanese name: Souryuu-sukashi-tenjikudai] Figures 1–4; Table 1

Rhabdamia spilota Allen & Kuiter 1994: 21 , fig. 2 (type locality: Bali, Indonesia); Allen & Adrim 2003: 14, fig. 34 (Indonesia); Gon & Randall 2003: 40, fig. 10 (Gulf of Aqaba, Red Sea); Allen et al. 2005: 265, unnumbered fig. (Indonesia); Allen & Erdmann 2012: 411, unnumbered fig. (Triton Bay, Indonesia); Allen et al. 2015: 269, unnumbered fig. (Indonesia); Yoshida 2017: 100, unnumbered fig. (Panay Island, Philippines).

Gymnapogon philippinus (not of Herre): Miura 2012: 33, unnumbered fig. (Chinen, Okinawa, Japan).

Holotype. NCIP 6121 , 38.8 mm SL, drop off at east end of Tulamben , Bali, Indonesia, 08°18′S, 115°37′E, hand net, 23–45 m depth, R. Kuiter, 24 May 1994.

Paratypes. 8 specimens, 20.9–34.8 mm SL. NCIP 6122–28, 3 specimens, 23.1–33.0 mm SL, WAM P. 30515- 0 0 1, 5, 20.9–34.8 mm SL, same data as holotype.

Non-type specimens. 61 specimens, 29.9–61.2 mm SL. RED SEA: AMS I. 38145-001, 48.8 mm SL, El Hameira, Sinai Peninsula , Gulf of Aqaba , 30°30′N, 34°55′E, 12 m, J. Randall & O. Gon, 25 April 1977 . THAILAND: KAUM –I. 59686, 51.6 mm SL , KAUM–I. 59689, 51.7 mm SL, KAUM–I. 59691, 55.0 mm SL, KAUM–I. 59692, 56.9 mm SL, KAUM –I. 59693, 57.2 mm SL, off Phuket, bottom trawl ; KAUM –I. 60980, 46.6 mm SL, off Phuket, purse seine. AUSTRALIA: CSIRO H 3443-02, 46.5 mm SL , CSIRO H 3443-03, 6, 41.4–47.8 mm SL, east of Sir Charles Hardy Islands , 11°54′S, 143°34′E, 21 m, 24 March 1993 ; CSIRO H 3451-01, 49.7 mm SL, York Peninsula , 11°12′S, 143°46′E, 33 m, 1 June 1993 ; NSMT-P 113800, 54.3 mm SL, NSMT-P 113801 , 14 , 48.1 –55.0 mm SL, eastern Indian Ocean , 24°56.1′S, 112°45.9′E, 90 m, R/ V Kaiyo-maru, 7 November 1975 . NEW CALEDONIA: BPBM 33869, 3, 50.3–56.5 mm SL, Chesterfield Islands , 20°37′04″S, 161°08′00″E, R/ V Alis, 31 August 1988 . PHILIPPINES: KAUM –I. 63043, 53.5 mm SL , KAUM –I. 63052, 50.0 mm SL, off Iloilo, Panay Island , 10°41′N, 122°35′E . SOUTH CHINA SEA: USNM 261180 , 53.7 mm SL, Macclesfield Bank , 16°05′30″N, 114°40–43′00″E, 76.8–80.0 m, R/ V Cape St. Mary, 13 June 1964 ; USNM 262762, 9, 29.9–39.6 mm SL, Macclesfield Bank , 15°49′24″–58ʹ48ʺN, 114°31′48″–33ʹ48ʺE, 82.3–84.1 m, R/ V Cape St. Mary, 15 June 1964 . JAPAN: KAUM –I. 495, 49.0 mm SL, Hami , Kagoshima, 31°20′N, 130°04′E, set net, 40 m, K. Nakahata, 24 February 2006 ; KAUM –I. 53981, 57.6 mm SL, off Kumano, Tanega-shima island , Kagoshima, 30°28′13″N, 130°58′32″E, set net, 25 m, M. Takayama, 9 April 2013 ; KAUM –I. 54004, 52.9 mm SL, off Kumano, Tanegashima island , Kagoshima, 30°28′13″N, 130°58′32″E, set net, 25 m, M. Takayama, 14 April 2013 ; KAUM –I. 54080, 58.4 mm SL, off Kumano, Tanega-shima island , Kagoshima, 30°28′13″N, 130°58′32″E, set net, 25 m, M. Takayama, 13 April 2013 ; KAUM–I. 54300, 58.3 mm SL, KAUM –I. 54301, 57.9 mm SL, off Kumano, Tanegashima island , Kagoshima, 30°28′13″N, 130°58′32″E, set net, 25 m, M. Takayama, 5 May 2013 ; KAUM–I. 54340, 56.6 mm SL, KAUM–I. 54341, 58.3 mm SL, KAUM–I. 54342, 56.5 mm SL, KAUM –I. 54343, 49.8 mm SL, off Hirota Port, Tanega-shima island , Kagoshima, 30°25′29″N, 130°58′50″E, set net, 20 m, M. Takayama, 4 May 2013 ; KAUM –I. 55487, 57.0 mm SL, Uchinoura Bay, Kimotsuki, Kimotsuki-gun , Kagoshima, 31°17′N, 131°05′E, set net, 40 m, M. Yamada, 11 June 2013 ; KAUM –I. 55994, 47.7 mm SL, Minamitane, Tanega-shima island , Kagoshima, 30°27′N, 130°58′E, set net, M. Yamada, 25 February 2013 ; KAUM –I. 62240, 61.2 mm SL, off Kumano, Tanega-shima island , Kagoshima, 30°28′13″N, 130°58′32″E, set net, 25 m, M. Takayama, 4 May 2014 ; KAUM–I. 62493, 60.4 mm SL, KAUM –I. 62497, 59.2 mm SL, off Kumano, Tanega-shima island , Kagoshima, 30°28′13″N, 130°58′32″E, set net, 25 m, M. Takayama, 3 May 2014 ; KAUM –I. 68226, 45.1 mm SL, Uchinoura Bay, Kimotsuki, Kimotsuki-gun , Kagoshima, 31°17′29″N, 131°06′59″E, set net, 40 m, K. Koeda, 16 January 2015 .

Diagnosis A species of Rhabdamia with the following combination of characters: dorsal-fin rays VI-I, 9; analfin rays II, 11–12 (modally 12); pectoral-fin rays 13–14 (modally 13); developed gill rakers 27–33 (modally 30– 31); gill rakers including rudiments 27–33 (modally 30); a black stripe from jaw tips to anterior margin of orbit; 3– 6 reddish-brown to blackish blotches on opercle and anterior of body; indistinct black pigment restricted to caudal fin outer margins.

Description. Meristics and morphometrics of the type and non-type specimens are shown in Table 1. Data for the holotype are presented first, followed by paratype or non-type data (if different) in parentheses.

Body oblong, moderately deep and compressed; deepest at first dorsal-fin origin. Dorsal and ventral profiles of head and body convex. Caudal peduncle moderately deep. Head large, compressed. Eye large, rounded, orbit diameter 3.3 (2.7–4.1) in HL. Mouth moderate in size, oblique, forming angle of ca. 40 degrees to horizontal axis of body. Posterior margin of maxilla extending beyond vertical through anterior margin of eye; posterior edge of maxilla slightly concave; supramaxilla absent. Upper-jaw length 2.6 (2.2–3.0) in HL. Lower jaw projecting, its tip thickened and fitting into median indentation in upper jaw. No enlarged caniniform teeth on jaws. Villiform teeth in 1–3 rows on both jaws; several tiny teeth on vomer; teeth absent on ectopterygoid. Scattered papillae on upper surface of tongue. Anterior nostril with short oval tube, uppermost margin of opening level with dorsal margin of pupil. Posterior nostril oval, opening vertically, without rim, uppermost margin below level of dorsal margin of orbit. Gill rakers slender, moderately long. Gill filaments shorter than gill rakers. Single, flat, obtuse opercular spine. Preopercular and opercular margins smooth.

Body scales cycloid, thin and deciduous. Lateral line well developed, more or less parallel with dorsal contour of body, ending a little beyond caudal-fin base (three pored scales posterior to hypural, last scale pointed). No scales on dorsal and anal fins, but a low sheath along bases of second dorsal and anal fins; small scales basally on caudal fin; midventral scales on bases of pelvic fins, paired fins otherwise lacking scales.

Vertebrae 10 + 14. Formula for supraneural bones, anterior neural spines and anterior dorsal pterygiophores 0/ 0/1/1+1/1/1+1/. Caudal skeleton ( Fig. 4 ): five hypurals (first to fourth hypurals firmly fused, fifth hypural free), three epurals, one parhypural, uroneurals and autogenous haemal spines absent.

First dorsal-fin origin posterior to vertical through pectoral-fin base; second spine of first dorsal fin damaged (second spine longest, its length 2.5–3.8 in HL). Posterior end of first dorsal-fin base anterior to vertical through posterior tip of depressed pelvic fin; all dorsal-fin soft rays branched. Second dorsal-fin origin anterior to vertical through anal-fin origin; second dorsal fin with concave margin; second dorsal-fin spine and rays damaged (first dorsal spine length of second dorsal fin 2.6–4.1 in HL; first soft ray of second dorsal fin longest, its length 1.5–2.3 in HL); all second dorsal-fin rays branched. Posterior end of second dorsal-fin base posterior to vertical through base of ninth (or eighth) anal-fin soft ray. Anal-fin origin below base of second soft ray of second dorsal fin; first spine of anal fin short, its length 12.0 (7.9–23.9) in HL; second anal spine damaged (its length 3.2–5.8 in HL); first soft ray of anal fin long, its length 1.9 (1.8–2.5) in HL; all anal-fin rays branched. Pelvic-fin origin anterior to vertical through origin of first dorsal fin; pelvic-fin spine long, its length 2.8 (2.6–3.9) in HL; first pelvic-fin soft ray longest, its length 2.0 (1.8–2.8) in HL. Posterior tip of depressed pelvic fin reaching to vertical through sixth spine base of first dorsal fin. Pectoral fin long, its length 1.1 (1.1–1.5) in HL, posterior tip extending beyond vertical through fourth soft ray of second dorsal fin; pectoral-fin base narrow, its width 5.7 (4.8–9.3) in HL. Caudal fin forked, length of upper lobe 1.2 (1.0–1.9) in HL. Anus midway between pelvic and anal fin origins.

Color of fresh specimens —Body semi-translucent, pinkish with silvery abdomen, 3–6 reddish-brown to blackish blotches on opercle and anteriorly on body below first dorsal-fin base. Two short reddish-brown to blackish stripes (sometimes one or none) above center of opercle. A longitudinal reddish-brown to blackish stripe on lateral surface of body from upper end of gill opening to below second dorsal-fin base (sometimes absent). Snout and tip of lower jaw yellowish with black pigmentation. Lower part of head silvery-white (rarely with some black pigmentation or a diffuse black stripe from posterior margin of preopercle to midpoint of opercle). Posteroventral margin of orbit to center of opercle silvery-white (rarely with diffuse black pigmentation). First and second dorsal fins translucent red, yellowish basally. Pectoral fin translucent yellowish-red. Pelvic and anal fins translucent red. Caudal fin translucent yellowish-red, with indistinct black pigmentation on outer margins.

Color of preserved specimens —Head and trunk pale yellow. Black stripe and blotches on head and body. All fins translucent.

Distribution. Currently known from the northern Indian Ocean (Red Sea and Andaman Sea) and western Pacific Ocean ( Japan, South China Sea, Philippines, Indonesia, New Caledonia and Australia). The northernmost and easternmost recorded ranges of the species are Uchinoura Bay, Kagoshima, Japan and Chesterfield Island, New Caledonia ( Fig. 3 ). Collection data for the specimens indicated capture depths from 12 to 90 m.

Remarks. Allen & Kuiter’s (1994) descriptions of R. spilota and supposed R. gracilis (hereinafter “ R. gracilis ”) indicated both as having 27–32 total gill rakers on the first gill arch, although examination of the two species concerned during this study showed that they differed from each other in gill raker numbers (27–33 in R. spilota vs. 23–27 in “ R. gracilis ”; Table 1). Allen & Kuiter (1994) also indicated that their “ R. gracilis ” had “subdermal black spots at the base of the lower caudal rays and black tips on one or both lobes in some specimens”. However, specimens of true Indo-West Pacific R. gracilis examined herein lacked black spots on the lower part of the caudal-fin base and had black pigmentation on the tips of the caudal-fin lobes. In addition, the preopercular margin of “ R. gracilis ” was described as weakly serrated or crenulated, but is smooth in true R. gracilis . Present indications point to “ R. gracilis ” being an undescribed species.

Allen & Kuiter (1994) included body depth in the diagnostic characters of R. spilota (3.7–3.8 in SL vs. 3.1–3.5 in SL for “ R. gracilis ”). The present examination of many R. spilota specimens indicated its body depth to be 3.2– 4.1 in SL, which broadly overlaps those of both “ R. gracilis ” and true R. gracilis (3.3–4.6 in SL; this study). Although Allen & Kuiter (1994) gave the number of total gill rakers (including rudiments) of the type specimens of R. spilota as 7 + 22, our re-examination of the type series showed total gill rakers numbered 9 + 22 in the holotype and 7–8 + 20–23 in the paratypes ( Table 1).

……continued on the next page Gon & Randall (2003) also compared specimens of R. spilota with supposed R. gracilis , in fact the same (undescribed) species studied by Allen & Kuiter (1994). Accordingly, differences between R. spilota and true R. gracilis have remained unclear to date. The present study revealed that R. spilota is distinguished from true R. gracilis by having modally 30 or 31 developed gill rakers (vs. 24 in R. gracilis ; Table 1), modally 30 gill rakers including rudiments (vs. 24 or 25; Table 1), a black stripe from the jaw tips to the anterior margin of the orbit (vs. snout and tip of lower jaw with black pigmentation), 3–6 reddish-brown to blackish blotches on the opercle and anterior of the body (vs. blotches absent), and indistinct black pigmentation restricted to the outer margins of the caudal fin (vs. pigmentation scattered over entire fin).

The largest individual of R. spilota examined here (KAUM–I. 62240, 61.2 mm SL) was collected from Tanega-shima island, Osumi Islands, Japan.

Figures

FIGURE 3. Distributional records of Rhabdamia spilota (based on specimens examined herein). Circles and stars indicate localities of previously and newly-recorded specimens, respectively.

FIGURE 4. Left side of caudal-fin complex of Rhabdamia spilota (KAUM–I. 62497, 59.2 mm SL, cleared and stained). Ct, terminal centrum; e, epural; h, hypural; hs, haemal spine; ns, neural spine; ph, parhypural; pu, pre-ural centrum.Scale 1 mm.