Scorpaenopsis obtusa Randall et Eschmeyer, 2002

Rusdianto,, Wibowo, Kunto & Limmon, Gino V., 2022, First specimen-based Indonesian record of a rare scorpionfish, Scorpaenopsis obtusa (Actinopterygii: Perciformes: Scorpaenidae), from Alor Island, Acta Ichthyologica et Piscatoria 52 (4), pp. 245-249 : 245

Scorpaenopsis obtusa Randall et Eschmeyer, 2002

English common name: shortsnout scorpionfish (Figs 1 , 2 , 3)

Material examined.

MZB.26532, 1 specimen, 91.1 mm SL, Ampera , Alor Barat Laut, Alor Island, Indonesia, 8°16ʹ03.7ʹʹS, 124°25ʹ33.1ʹʹE, 5 m depth, hand net, K. Wibowo, 26 February 2022 .

Description.

Counts and proportional measurements [given below as percentages of SL and HL (for head characters; presented in parenthesis)] of presently reported specimen (91.1 mm SL) were as follows: dorsal fin with 12 spines and 9 soft rays; pectoral fin with 1 uppermost unbranched ray, 6 branched rays, 12 lower unbranched rays, total 19 rays; longitudinal scale rows 38; pored lateral-line scales 20; scales above lateral line 5, below 12; gill rakers on upper limb of first gill arch 4, lower limb 9, total 13; body depth 44.5% of SL; body width 30.2; head length 45.6; snout length 11.8 (26.0% of HL); orbit diameter 10.3 (22.7); interorbital width at posterior end of preocular spine bases 11.1 (24.3); caudal-peduncle depth 12.0; caudal-peduncle length 15.7; upper-jaw length 25.9 (57.0); pre-dorsal-fin length 38.5; pre-anal-fin length 71.5; pre-pelvic-fin length 39.3; first dorsal-fin spine length 7.8; second dorsal-fin spine length 11.9; third dorsal-fin spine broken; fourth dorsal-fin spine length 15.8; eleventh dorsal-fin spine length 10.8; twelfth dorsal-fin spine length 12.9; longest dorsal-fin soft ray length 19.2 (third ray); first anal-fin spine length 9.4; second anal-fin spine length 17.5; third anal-fin spine length 15.6; longest anal-fin soft ray length 23.0 (second ray); caudal-fin length 26.9; pectoral-fin length 39.0; pelvic-fin spine length 19.3; longest pelvic-fin soft ray length 29.2 (second ray); head width 21.5 (47.3); postorbital length 27.3 (59.9); maxillary depth 7.6 (16.6).

Body wide anteriorly, progressively compressed posteriorly. Mouth large, oblique, positioned at angle of about 60° to horizontal axis of head and body. Posterior margin of maxilla extending beyond line from posterior margin of orbit to edge of retroarticular. Vomerine plate forming V-shaped patch, with rudimentary teeth. Palatine teeth absent. Nasal spine with 3 spinous points. Ascending process of premaxilla intruding into interorbital space, its posterior margin level with anterior margin of pupil. Median interorbital ridge absent. Interorbital ridges distinct; space between interorbital ridges shallow and broad, its width about half of orbit diameter. Preocular and supraocular spines small, directed upward. Postocular spine large, with 3 points, broadly joined to tympanic spine at base. Tympanic with 2 spinous points, located between postocular spines. Coronal spine absent. Occipital pit deep, its width greater than length. Parietal and nuchal spines about equal size, joined at base. Sphenotic with 2 small spines. Postorbital with 2 small spines. Pterotic spine simple, larger than supraocular spine. Upper posttemporal spine larger than lower spine. Space between parietal, nuchal, pterotic, and lower posttemporal spines with two small spines. Supracleithral spine asymmetric, with 3 and 2 pointed spines on left and right sides, respectively. Cleithral spine flattened, strongly pointed. Anterodorsal lacrimal spine present. Single small spines on middle and posterior end of lacrimal ridge. Anterior lacrimal spine directed anteriorly, its tip reaching dorsal margin of upper lip; two additional small points on posterior margin. Posterior lacrimal spine directed ventrally, larger than anterior spine, its tip not reaching dorsal margin of upper lip; an additional spine present on anterior margin; posterior lacrimal spine associated with short fimbriate flap. Lateral lacrimal spine present, its size approximately equal to anterodorsal lacrimal spine. Suborbital ridge with 3 spines. Suborbital pit present. Preopercle with 5 spines; uppermost spine largest, with supplemental preopercular spine on base; second spine sharp; third to fifth spines blunt. Upper opercular spine with 2 points; lower opercular spine simple, with median ridge.

Lateral surface of body covered with weak ctenoid scales, becoming cycloid ventrally. Exposed cycloid scales covering pectoral-fin base. Cycloid scales embedded in thin skin covering anteroventral surface of body. Body scales not extending onto fin rays or membranes, except basally on seven uppermost pectoral fin rays. Lateral line complete, first two scales with spine-like projection at end of sensory tube. No scales on head.

Numerous tiny papillae scattered on dorsal and lateral surfaces of head, including snout, interorbital space, outer margin of eye membrane, preopercle, and opercle. No papillae on occipital pit. Tentacle on upper posterior edge of low membranous tube associated with anterior nostril. Fleshy tentacle associated with posterior lacrimal spine. Several short, slender tentacles on lateral surface of maxilla. Broad, skin flap associated with each of third to fifth preopercular spines. Many small, round flaps on ventral surface of head and anteroventral surface of body. Many slender tentacles associated with posterior margin of opercle, pored lateral scales scattered on lateral and dorsal surfaces of body, and pectoral and caudal fins.

Origin of first dorsal-fin spine above supracleithral spine. Posterior margin of opercular membrane level with posterior margin of third dorsal-fin spine base. Posterior tip of pectoral fin extending beyond third anal-fin spine base. Posterior tip of pelvic fin extending slightly beyond anus when depressed. Origin of last dorsal-fin spine just above origin of first anal-fin spine.

Color when fresh (Figs 1 , 3A ). Head and body mottled dark reddish-brown to white. Dorsal fin whitish to reddish-brown, distinct black blotch on base of spinous portion between fourth and eighth spines. Pectoral fin outer surface pinkish-white, blackish basally, with blackish band near tip; inner surface orange, with broad black blotch basally on each of uppermost four and lowermost seven rays, black submarginal band (progressively less distinct on lower unbranched rays), axil and base of membrane of fifth to fourteenth rays white with small black spots. Pelvic fin black, with white distal margin. Anal fin dark reddish with numerous tiny spots and white posterior margin. Caudal fin whitish, with broad pinkish band.

Figures

Figure 1. Fresh specimen photograph of Scorpaenopsis obtusa, MZB. 26532, 91.1 mm SL, collected from Alor Island, Indonesia.

Figure 2. Distributional records of Scorpaenopsis obtusa, based on previous studies (circles) and the presently reported study (star). Closed and open symbols indicate specimen- and underwater photograph-based records, respectively.

Figure 3. Inner surface of pectoral fin (fresh condition) (A), head (showing line from posterior margin of orbit to posteroventral tip of retroarticular) (B), and caudal fin (C) of Scorpaenopsis obtusa, MZB. 26532, 91.1 mm SL, collected from Alor Island, Indonesia.