Scorpaenodes corallinus Smith, 1957

Hoshino, Kazuo, Sakurai, You & Motomura, Hiroyuki, 2023, First Japanese Records of the Indo-Pacific Scorpionfish (Scorpaenidae) Scorpaenodes corallinus, with a Re-evaluation of Coronal Spines as a Diagnostic Character, Species Diversity 28 (1), pp. 123-131 : 123-129

Scorpaenodes corallinus Smith, 1957

[English name: Coral Scorpionfish; new standard Japanese name: Ichigo-isokasago] ( Figs 1–3 ; Tables 1, 2)

Scorpaenodes corallinus Smith, 1957: 64 , pl. 3-fig. E, fig. 5 (type locality: Pinda Island, Mozambique); Randall 1973: 184 (Tahiti, Society Islands, French Polynesia); Eschmey- er and Randall 1975: 283, fig. 5c [Oahu, Hawaiian Islands; Moorea, Society Islands; Mentawei (currently Mentawai) Islands, Indonesia]; Allen 2000: 86 ( Christmas Island, Australia); Allen and Adrim 2003: 29 [Mentawei (currently Mentawai) Islands]; Randall 2005: 120 (Society Islands); Mundy 2005: 328 (Oahu); Randall 2007: 174 (Hawaiian Islands); Fricke et al. 2011: 378 (Loyalty Islands, New Caledonia); Allen and Erdmann 2012a: 229 (Mentawai Islands).

Japanese specimens examined. KAUM –I. 42871, 95.5 mm SL, Araha Beach, Araha, Chatan , Nakagami , Okinawa Island , Okinawa Islands , 26°18′15″N, 127°45′30″E, Y . Sakurai , 29 May 2011, stranded; KAUM –I . 49674, 70.9 mm

SL, KAUM –I. 49675, 82.2 mm SL, and KAUM –I. 49676, 81.6 mm SL, Toguchi, Yomitan, Nakagami , Okinawa Island , Okinawa Islands , 26°22′01″N, 127°44′15″E, Y . Sakurai , 30 September 2012, stranded; KAUM –I . 51625, 89.1 mm SL, Toguchi, Yomitan, Nakagami , Okinawa Island , Okinawa Islands , 26°22′01″N, 127°44′15″E, Y . Sakurai , 17 September 2012, stranded; KAUM –I . 58534, 80.0 mm SL, off Tomori, Yoron Island, Amami Islands , 27°02′N, 128°24′E, 10–12 m depth, M . Meguro et al ., 24 January 2014; KAUM –I . 65264, 85.9 mm SL, Hama Fishing Port, Nakagusuku, Nakagami , Okinawa Island , Okinawa Islands , 26°09′06″N, 127°28′25″E, Y . Sakurai , 9 July 2014, stranded; KAUM –I . 68850, 90.9 mm SL, Toguchi Beach, Toguchi, Yomitan , Nakagami , Okinawa Island , Okinawa Islands , 26°22′08″N, 127°44′05″E, Y . Sakurai , 13 October 2014, stranded; KAUM –I . 123221, 76.8 mm SL, KAUM –I. 123222, 81.2 mm SL, KAUM –I. 123223, 91.8 mm SL, KAUM –I. 123224, 91.4 mm SL, KAUM –I. 123225, 91.5 mm SL, and KAUM –I. 123226, 82.4 mm SL, Toguchi Beach, Toguchi, Yomitan , Nakagami , Okinawa Island , Okinawa Islands , 26°22′08″– 26°21′31″N, 127°44′01″– 127°44′10″E, Y . Sakurai, 30 September 2018, stranded; URM-P 41469, 82.4 mm SL, Araha Beach, Araha , Chatan , Nakagami, Okinawa Island, Okinawa Islands, H . Ishimori and M . Kume , 17 October 2001 .

Japanese underwater photograph examined. KPM-NR 80574, Unanzaki, Aka Island, Kerama Islands, 18 m depth, 26 October 2001, taken by A. Moriyama.

Comparative Indo-Pacific material. MOZAMBIQUE: SAIAB 301 , holotype of S . corallinus ( Fig. 3 ), 64.4 mm SL, Pinda Island, 14°12′59″S, 40°45′59″E, J . L. B. Smith , 2 October 1956; SAIAB 368 , paratype of S . corallinus, 81.9 mm SL, Matemo Island, Querimba Archipelago , 12°15′00″S, 40°34′00″E, August 1951; SAIAB 372 , paratype of S . corallinus, 66.4 mm SL, Tekomaji (currently Tecomagi or Tecomaji ) Island , Querimba Archipelago , 10°47′00″S, 40°39′00″E, July 1951; SAIAB 373 , paratype of S . corallinus, 63.2 mm SL, Pinda Island, 14°12′59″S, 40°45′59″E, August 1950; SAIAB 375 , paratype of S . corallinus, 55.5 mm SL, Mozambique Island, 15°02′00″S, 40°39′00″E, August 1950; SAIAB 376 , 2 paratypes of S . corallinus, 65.3 and 79.8 mm SL, Tekomaji (currently Tecomagi or Tecomaji ) Island , Querimba Archipelago , 10°47′00″S, 40°39′00″E, August 1950 . TANZANIA: SAIAB 369 , 2 paratypes of S . corallinus, 75.4 and 86.8 mm SL, Zanzibar Island , 6°10′00″S, 39°11′00″E, September1952; SAIAB 371 , paratype of S . corallinus, 70.6 mm SL, Pemba Island, 5°08′00″S, 39°40′00″E, J . L. B. Smith and M . M. Smith , 1952 . KENYA: SAIAB 370 , 2 paratypes of S . corallinus, 70.4 and 77.8 mm SL, Shimoni , 4°39′00″S, 39°23′00″E, August 1954 . SEYCHELLES: SAIAB 374 , paratype of S . corallinus, 78.6 mm SL, Aldabra Island, 9°26′00″S, 46°20′00″E, J . L. B. Smith , November 1954 . NEW CALEDONIA: USNM 324423 , 2 specimens, 78.8 and 80.9 mm SL, Ouvea Atoll , Loyalty Islands, 20°37′19″S, 166°16′12″E, 9–12 m depth, J .-L. Menou et al ., 18 November 1991; USNM 324424 , 79.8 mm SL, Ouvea Atoll, Loyalty Islands, 20°29′12″S, 166°19′18″E, 3–10 m depth, J . Williams et al ., 19 November 1991.

Diagnosis. A species of Scorpaenodes with the following combination of characters: usually 8 dorsal-fin soft rays; 41–47 (mode 43) scale rows in longitudinal series; nasal spines present; scales absent on underside of head; body and fins generally reddish, with scattered numerous white spots; dark blotches on opercle and subopercle absent or weak (if present on opercle); a weak vertical black band basally on pectoral fin.

Description. Counts and measurements, and spination of coronal spines given in Tables 1 and 2, respectively. Dorsal fin with 13 spines (5th spine divided into two in KAUM–I. 123223) and 8 soft rays (9 in KAUM–I. 42871); usually fourth or fifth spine longest; membrane of spinous portion of dorsal fin moderately incised; fourth soft ray longest, its length about 1.2 times that of longest dorsal-fin spine; posterior branch of last soft ray joined by membrane to caudal peduncle. Anal fin with 3 spines and 5 soft rays; second spine longest; all soft rays branched; second soft ray longest, its length greater than that of longest dorsal-fin soft ray (slightly shorter in KAUM–I. 123224); posterior branch of last soft ray not joined by membrane to caudal peduncle. Pectoral-fin rays usually 17 or 18 (19 on right side in KAUM–I. 123223); lower unbranched rays thickened; upper half of posterior margin of fin truncate, lower half rounded. Pelvic fin with 1 spine and 5 soft rays, all soft rays branched;

Continued.

second soft ray longest (rarely fifth in KAUM–I. 49676), its length subequal to postorbital length; last soft ray joined by membrane to abdomen for about one-third its length. Caudal fin with 9 or 10 branched rays; posterior margin of fin rounded. Gill rakers 11–14; fourth gill slit closed by membrane; longest raker on first gill arch subequal to or slightly longer than gill filaments around angle of arch. Branchiostegal rays 7. Swimbladder present.

Body moderately compressed anteriorly, progressively more compressed posteriorly. Nape and anterior body moderately arched. Body depth less than head length. No distinct tentacles on head and body except for anterior nostril, small and short if present. Tiny ciliary processes present on snout, usually absent on upper and lower jaws, including symphysial knob, and around eye. Lacrimal ridge tentacle absent. A long wide tentacle on posterior edge of low membranous tube associated with anterior nostril, just reaching or passing over anterior margin of posterior nostril when laid back. Pectoral-fin axil without skin flaps. Exposed ctenoid scales covering head, except for parts of jaws and snout. Exposed ctenoid scales covering most of pectoral-fin base, some weakly ctenoid or cycloid on lower part, none embedded in thin skin. Body scales ctenoid on lateral surface, cycloid on abdomen; extending onto basal rays and membranes of dorsal, anal, pectoral and caudal fins. Lateral line present; pored lateral-line scales 20–25.

Mouth large, slightly oblique. Upper edge of maxilla with well-developed ridge anteriorly (sometimes a small spine on left side in KAUM–I. 42871, 49674, 49675, 123226, both sides in KAUM–I. 123225). Posterior margin of maxilla just reaching vertical through posterior margin of orbit. Lower jaw with a well developed symphysial knob. Width of symphysial gap separating premaxillary teeth bands greater than width of each band. Upper jaws with a band of villiform teeth, jaw length and width greater than lower jaws. Teeth of upper jaws clearly visible from ventral view. Villiform teeth covering entire vomerine plate. Palatine teeth absent. Underside of lower jaw smooth, without ridges. Dorsal profile of snout rising gently. Nasal spine simple, sharp (rounded on left side in KAUM–I. 51625, 123224, right side in KAUM–I. 123221), directed dorsally, its length subequal to anterior nostril diameter. Ascending process of premaxilla not intruding into interorbital space, its posterior margin reaching level with posterior margin of posterior nostril in dorsal view. Median interorbital ridge well developed. Interorbital ridges usually present. Interorbital spine usually absent (present on right side in KAUM–I. 123221, both sides in KAUM–I. 58534). Preocular spine usually simple, sharp (rounded in KAUM–I. 123224), directed posterodorsally, usually without a tentacle (present in KAUM–I. 58534); tip of spine reaching level with upper margin of pupil in lateral view. Supraocular and postocular spines simple (two of former on right side in KAUM–I. 123224; two of latter on right side in KAUM–I. 68850), moderately developed, each usually without a tentacle (present in KAUM–I. 58534). Tympanic spine simple, directed posterodorsally (one very small spine in front of tympanic on right side in KAUM–I. 123221), usually without a tentacle. Coronal spine usually simple, directed posterodorsally (absent on left side in KAUM–I. 42871, 49674, 123221, 123224, right side in KAUM–I. 68850, 123225, 123226, both sides in KAUM–I. 51625, URM-P 41469; 3 spines in KAUM–I. 123223), without a tentacle. Pretympanic spine absent. Occipital region nearly flat, surrounded laterally by tympanic and parietal spines, an indistinct ridge between spines. Parietal and nuchal spines simple, joined at base (connected at ridge in KAUM–I. 42871), each usually without a tentacle, base of latter with a distal ridge. Sphenotic usually with 1–7 small spines, uppermost often large and surrounding posterodorsal margin of orbit. Postorbital with 2–7 tiny spines (absent on right side in KAUM–I. 123223). Pterotic spine usually simple (two on right side in KAUM–I. 123225), usually without a tentacle; a posterodorsally directed ridge usually present above pterotic spine. Upper and lower posttemporal spines simple, pointed (former rounded on left side in KAUM–I. 49676, right side in KAUM–I. 123225, both sides in URM-P 41469), each usually without a tentacle. Upper posttemporal spine shorter than lower posttemporal spine. Lower posttemporal spine base length subequal to or a little shorter than that of pterotic spine. Supracleithral spine simple, weakly wavy. Cleithral spine simple, with a weak ridge.

Lacrimal bone with 1 ridge and 1 spine on upper margin, anterior ridge extending strongly laterally, posteriorly usually with a single lateral lacrimal spine; 2 ridges on lower margin, posterior ridge longer than anterior ridge, directed downward (margins not reaching dorsal margin of upper lip). Suborbital usually with 2 spines, rarely 3 or 4; first below posterior margin of pupil, second behind orbit; usually one small spine or low ridge below second (absent on left side in KAUM–I. 123222, right side in KAUM–I. 42871, 49675, both sides in KAUM–I. 123224, URM-P 41469). Space between ventral margin of eye and suborbital spines narrow. Suborbital pit absent. Preopercle with five spines; upper 2 spines large and distinct, lower 3 small and indistinct (embedded in thin skin); uppermost spine largest with a supplemental preopercular spine on base; usually one small spine between upper 2 spines (absent on left side in KAUM–I. 123223, right side in KAUM–I. 123226, both sides in KAUM–I. 51625, 123221, 123224). Upper opercular spine simple, flat, posterior tip not reaching opercular margin. Lower opercular spine simple, with a strong ridge, posterior tip just reaching to or slightly passing over opercular margin. No ridges between upper and lower opercular spines.

First dorsal-fin spine origin above supracleithral spines. Posterior margin of opercular membrane reaching to vertical between second and fourth dorsal-fin spine bases. Posterior tip of pectoral fin just reaching or slightly short of vertical through first anal-fin spine base. Pelvic-fin spine origin slightly anterior to or reaching vertical through origin of pectoral fin. Posterior tip of depressed pelvic fin not reaching anus. Origin of first anal-fin spine slightly posterior to or reaching vertical through origin of last dorsal-fin spine.

Color when fresh. Based on color photographs of KAUM specimens ( Fig. 1 ) and underwater photograph KPM-NR 80574 ( Fig. 2 ). Body and fins generally reddish, with numerous scattered white spots. Dark blotches on opercle and subopercle absent or weak (if present on opercle). White vertical band anteriorly on caudal peduncle and basally on caudal fin.

Distribution. Scorpaenodes corallinus has been record- ed from Mozambique [Pinda, Matemo and Tekomazi (currently Tecomagi or Tecomaji) Islands], Tanzania ( Zanzibar and Pemba Island), Kenya (Shimoni), the Seychelles (Aldabra and Assumption Islands), Indonesia [Mentawei (currently Mentawai) Islands], Australia ( Christmas Island), the Hawaiian Islands (Oahu), New Caledonia (Loyalty Islands), and French Polynesia (Society Islands) ( Smith 1957; Randall 1973, 2005, 2007; Eschmeyer and Randall 1975; Allen 2000; Allen and Adrim 2003; Mundy 2005; Fricke et al. 2011; Allen and Erdmann 2012a). Dor (1984) and Goren and Dor (1994) listed the species from the Red Sea, but without supporting evidence, and Poss and Motomura (2022) excluded the Red Sea from the distributional range of the species. This study includes the first records of S. corallinus from Japan [15 specimens from Okinawa Island (Okinawa Islands) and Yoron Island (Amami Islands), and 1 photographic record from Aka Island (Kerama Islands)].

Remarks. Scorpaenodes corallinus can be distinguished from all Indo-Pacific members of the genus by coloration, viz., body and fins generally reddish, with numerous scattered white spots ( Smith 1957) ( Figs 1 , 2 ) [such coloration not found in all congeners ( Eschmeyer and Randall 1975)], dark blotches on the opercle and the subopercle absent or weak (if present on the opercle) ( Figs 1 , 2 ) [vs. one or two blotches on the opercle in S. guamensis and S. steenei Allen, 1977 ( Allen 1977; Motomura et al. 2016), and a blotch on the subopercle in S. evides ( Jordan and Thompson, 1914) and S. englerti Eschmeyer and Allen, 1971 ( Eschmeyer and Allen 1971; Motomura et al. 2010)], and a weak vertical black band basally on the pectoral fin [vs. a distinct band present in S. varipinnis Smith, 1957 ( Eschmeyer 1986; Shinohara 1998)].

With the exception of the opercular blotch condition, S. corallinus is similar to the co-occurring species S. guamensis in overall body appearance. However, S. corallinus differs from the latter in several proportions related to head length: viz., head length [46.0–49.6% (mean 47.8%) SL in S. corallinus vs. 39.6–48.2% (43.5%) in S. guamensis ; Motomura et al. (2016) erroneously gave the values as 10.1–48.2%], snout length [10.9–13.6% (12.2%) vs. 8.2–12.5% (10.2%)], upperjaw length [23.8–25.9% (24.7%) vs. 19.4–23.7% (21.1%)], postorbital length [20.0–23.9% (22.5%) vs. 18.5–22.8% (20.9%)], pre-dorsal-fin length [41.9–47.0% (44.6%) vs. 36.4–43.1% (39.8%)], and pre-pelvic-fin length [39.7–47.2% (43.0%) vs. 35.5–42.9% (39.1%)] [data for S. guamensis from Motomura et al. (2016)].

Scorpaenodes corallinus differs from other Indo-Pacific congeners in having nasal spines [vs. absent in S. albaiensis (Evermann and Seale, 1907) , S. bathycolus Allen and Erdmann, 2012 , and S. minor (Smith, 1958) ( Motomura et al. 2009; Allen and Erdmann 2012b)], the underside of the head without scales [vs. scaled in S. tribulosus Eschmeyer, 1969 ( Eschmeyer 1969b; Eschmeyer and Rama Rao 1972)], more than 41 scale rows in the longitudinal series [vs. fewer than 35 scale rows in S. hirsutus ( Smith, 1957) and S. kelloggi (Jenkins, 1903) ( Hoshino and Motomura 2021) ], and usually 8 dorsal-fin soft rays [vs. 9 or 10 soft rays in all remaining species ( Eschmeyer and Rama Rao 1972; Poss 1999; Greenfield and Matsuura 2002)].

Smith (1957) distinguished S. corallinus from S. guamensis by the presence of coronal spines (“postfrontal spines” in Smith 1957) (vs. absence of such spines). However, examination of specimens of S. corallinus in this study showed a frequent lack of spines on the head, regardless of specimen size or locality; such variation was also apparent in the type series ( Table 2). In addition, a number of other variations were apparent in the head spination (see detailed species’ description above), and it is unsurprising that “presence of coronal spines” is an unreliable diagnostic character for S. corallinus .

The new standard Japanese name “Ichigo-isokasago” is proposed for the species, based on KAUM–I. 58534, 80.0 mm SL, collected off Tomori, Yoron Island, Amami Islands, Japan. “Ichigo” means strawberry, a reference to the reddish body coloration, and “isokasago” is the common Japanese name for the genus Scorpaenodes .

Figures

Fig. 1. Fresh specimen of Scorpaenodes corallinus (KAUM–I. 58534, 80.0mm SL, off Tomori, Yoron Island, Amami Islands, Japan).

Fig. 2. Underwater photograph of Scorpaenodes corallinus from Japan (KPM-NR 80574, Unanzaki, Aka Island, Kerama Islands, 18m depth, 26 October 2001, taken by A. Moriyama).

Fig. 3. Holotype of Scorpaenodes corallinus (SAIAB 301, 64.4mm SL, Pinda Island, Mozambique).