Spottobrotula mahodadi Cohen and Nielsen, 1978

Matsunuma, Mizuki, Yoshida, Tomohiro & Motomura, Hiroyuki, 2017, Records of Spottobrotula mahodadi (Ophidiiformes: Ophidiidae) and Hapalogenys bengalensis (Perciformes: Hapalogenyidae) from the Andaman Sea, with a Note on the Fresh Coloration of S. mahodadi, Species Diversity 22, pp. 73-79 : 73-78

publication ID	https://doi.org/ 10.12782/sd.22_73
persistent identifier	https://treatment.plazi.org/id/03EE8786-8C3C-8715-FCA4-A5B6AD9CFC2E
treatment provided by	Felipe
scientific name	Spottobrotula mahodadi Cohen and Nielsen, 1978
status

Treatment

Spottobrotula mahodadi Cohen and Nielsen, 1978 View in CoL ( Figs 1 View Fig , 2 View Fig ; Table 1)

Material examined. KAUM –I. 33115, 308.6 mm SL, Andaman Sea (obtained at fish market at Mahachai, Samut Prakan Province, Thailand), bottom trawl; THNHM-F 13331, 267.6 mm SL, Andaman Sea (obtained at fishing port at Bang Rin, Mueang Ranong, Ranong Province, Thailand), bottom trawl .

Description. Meristics and measurements expressed as percentages of SL shown in Table 1. Body robust and oblong, well compressed posteriorly, with pointed caudal fin; lateral line slightly upwardly curved above pectoral fin, reaching caudal-fin base; anus just before anal-fin origin. Head moderately large, its length 4.2–4.3 in SL; snout blunt, slightly protruding beyond upper jaw; mouth moderately large, maxilla expanded posteriorly, with slightly concave posterior margin, extending beyond vertical through posterior margin of orbit; lower jaw slightly protruding beyond tip of upper jaw; lips with numerous papillae; eyes moderately large, orbit diameter smaller than snout length, snout length 1.3 times orbit diameter; anterior nostril located at approximate midpoint of straight line between anterior margin of eye and snout tip, with very short raised rim and small skin flap; posterior nostril a simple pore just in front of eye. Both jaws with narrow teeth bands of ca. 5–7 rows of small, pointed conical teeth anteriorly, width of teeth band decreasing posteriorly; palatine with moderately long teeth band of ca. 7 irregular rows of small pointed teeth, width of teeth band decreasing posteriorly; vomerine teeth band subtriangular with posterior margin deeply concaved, its anterior tip broad and rounded, with many small, conical teeth; an elongate median tooth patch on basibranchial. Opercle with a short strong spine, its tip not reaching posterior margin of gill cover; no spines on preopercle. Anterior gill arch with a small knob and 3 short robust rakers on upper limb, a long raker at angle, 6 or 7 long rakers on lower limb, and 7 small knobs on hypobranchial segment; longest raker slightly shorter than longest gill filament. Infraorbital pores 6, comprising 3 large slit-shaped anterior pores and 3 very small posterior pores; supraorbital pore single; mandibular pores 6; lower preopercular pore single. Head and body, including maxilla, covered with overlapping, elongate cycloid scales; small cycloid basal scales extending onto almost entire surface of dorsal and pectoral fins, and about basal half of anal and caudal fins; lips, ventral surface of lower jaw, pectoral axilla, and branchiostegal membrane without scales. Dorsal-fin origin above pectoral-fin base; anal-fin origin clearly anterior to mid-body, situated below base of 28th or 31st dorsal-fin ray; caudal fin connected with dorsal and anal fins. Pectoral fin moderately large with rounded contour; a prominent skin flap above its base. Pelvic-fin base situated below preopercle, rays thick, extremely long, extending beyond a vertical through pectoral-fin tip but clearly not reaching anus when depressed, with numerous small papillae distally.

Fresh coloration ( Fig. 1 View Fig ). Head and body entirely greyish-white or pale brown (head silvery-white in THNHM-F 13331 due to missing scales); anterodorsal body and dorsal head blackish; anus whitish; lateral line with blackish tinge. Body with about 26 (THNHM-F 13331) or 10 (KAUM–I. 33115; partially faded due to missing scales) rounded dark brown to black spots, their size slightly smaller than orbit diameter, irregularly scattered on upper two-thirds of body, including ca. 7 spots along dorsal-fin base in THNHM-F 13331 (condition unconfirmed in KAUM–I. 33115). Iris dark yellow in KAUM–I. 33115, dark red in THNHM-F 13331 (most likely bloodied); orbit rim blackish marginally. Ground color of dorsal, anal, and caudal fins greyish-white or pale brown. Dorsal fin with ca. 13 (THNHM-F 13331) or 7 (KAUM–I. 33115) dark brown to black spots, including a large spot (slightly larger than orbit diameter) on anterior- most portion of fin close to fin origin, similar sized spot at level of mid-body, remaining smaller spots being scattered irregularly. Posteriormost portion of dorsal fin, caudal fin and entire anal fin with broad black margin, its width one third of fin height on anterior portion of anal fin. Pectoral fin black. Pelvic-fin rays white, with slight blackish tinge. In preserved condition, head, body and fins becoming darker; spot marking clearly retained.

Remarks. The present specimens are clearly identified as Spottobrotula in having the following diagnostic characters proposed by Nielsen et al. (1999, 2014): dorsal-fin origin situated before the third vertebrae; the head and body fully scaled; the pelvic fins with two rays in each bound together with tough skin; no spines on the preopercle; an opercular spine short, not reaching the posterior margin of the opercle; a prominent skin flap above base of the pectoral fin; 10 prolonged gill rakers on the anterior gill arch; 29 or 40 pseudobranchial filaments; a single median basibranchial tooth patch; granular teeth present on the palatines; 16 precaudal vertebrae; dorsal part of the head and body with rather large dark spots; and the dorsal fin with about two large black blotches.

In their review of Spottobrotula, Nielsen et al. (2014) recognized three species, S. mahodadi , S. mossambica , and S. persica , describing the latter two as new. The present specimens were identical with S. mahodadi , having the following diagnostic characters described by Nielsen et al. (2014): pelvic fins located below the preopercle (versus below the end of the upper jaw in S. mossambica and S. persica ); pre-pelvic-fin length 15.0%–16.4% SL (17.5% SL in holotype) (versus 10.5%–13.0% SL in S. mossambica ; 13.0%–14.0% SL in S. persica ); scale rows between the dorsal-fin origin and lateral line 18 (versus 14 or 15 in both species); and pectoralfin rays 30 (versus 23–26; 23 or 24, respectively). Moreover, specific dark spots on the sides of the body extending onto the dorsal fin of the present specimens matched that feature of the S. mahodadi holotype (versus a broad dark band from the eye to behind the pectoral fin and three black ocelli on the dorsal fin in S. mossambica ; and no black markings on the head or body in S. persica ) ( Cohen and Nielsen 1978; Nielsen et al. 2014). Some minor meristic and morphometric differences found between the present specimens and the holotype of S. mahodadi are simply due to limited material ( Table 1). Nielsen et al. (2014) also regarded the numbers of long rakers on the anterior gill arch and pseudobranchial filaments as diagnostic for the species of Spottobrotula , viz., 10 (present specimens) or 11 (holotype) gill rakers, and 29 or 40 (present specimens) and 35 (holotype) pseudobranchial filaments in S. mahodadi ; 9–11 and 30–42, respectively, in S. mossambica ; and 10–12 and 32–35, respectively, in S. persica , but the ranges of these counts clearly overlap.

Differences of the numbers of fin rays, gill rakers, pseudobranchial filaments, and the vertebrae between the present specimens and the holotype of S. mahodadi ( Table 1) are most likely due to limited number of materials. These meristic characters, except for the caudal-fin rays, are considerably variable for the congener, S. mossambica (based on 14 specimens) ( Nielsen et al. 2014). Differences of the number of dark spots on the body and median fins among the present specimens and the holotype of S. mahodadi are tentatively regarded as the intraspecific variations. Examination of more specimens is necessary to determine what factors (e.g., the body size and sex), if any may be related to such morphological differences in S. mahodadi .

Spottobrotula mahodadi was originally described by Cohen and Nielsen (1978) on the basis of the holotype collected off Barren Island (Andaman Islands), Andaman Sea ( Fig. 2 View Fig ). Cohen and Nielsen (1982) subsequently recorded an additional specimen collected off Oman (Arabian Sea), later followed by Manilo and Bogorodsky (2003), who listed S. mahodadi in their checklist of fishes of the Arabian Sea. However, Nielsen et al. (2014) recently re-identified the Omani specimen as a new species, S. mossambica . Accordingly, the present specimens of S. mahodadi from the Andaman Sea represent only the second valid record of the species.

Color photographs of the present specimens taken prior to preservation enabled the fresh coloration of S. mahodadi to be described for the first time. The original description of the species was based solely on the preserved holotype. In fresh condition, with the exception of the above-mentioned differences in dark markings, S. mahodadi is clearly distinguished from S. mossambica by its uniformly dark-brownish body and fins, whereas the latter species has yellowishbrown median fins and a light grey head with pale rose jaws ( Nielsen et al. 2014: fig. 7b). The fresh coloration of S. persica remains unknown.

The present specimen, THNHM-F 13331 , collected by bottom trawl and obtained at a fish landing port in Mueang Ranong, Ranong Province, Thailand, lacks precise locality details ( Fig. 2 View Fig ) . The fishing boats from Ranong Province operate both in Thai and Thai-Myanmar boundary waters and some of them can operate in Myanmar water concessions ( Panjarat 2008) . Although the other specimen, KAUM –I . 33155, was obtained at a local fish market at Mahachai near Bangkok, also without precise collection locality details, it was apparently of Andaman Sea origin, according to a local fish seller . The holotype of S . mahodadi was collect- ed at a depth of ca. 40 m ( Nielsen et al. 2014). The present specimens lack collection depth data, but the major fishing grounds for demersal fishes are at depths of less than 100 m along the Andaman Sea coast of Thailand ( Chullasorn 1998) .

Hapalogenys bengalensis Mohapatra, Ray, and Kumar, 2013 ( Figs 2 View Fig , 3 View Fig ; Table 2)

Material examined. KAUM –I. 33393, 122.8 mm SL, Andaman Sea (obtained at fishing port at Bang Rin, Mueang Ranong, Ranong Province, Thailand), bottom trawl .

Description. Meristics and measurements expressed as percentages of SL shown in Table 2. Body deep, moderately compressed; caudal peduncle short, low; lateral line curved upward above pectoral fin, extending slightly onto caudal fin. Head moderately large, 2.4 in SL; orbit moderately large, slightly greater than interorbital width; nasal pores in front of orbit, anterior nostril with low raised rim with posterior flap, posterior nostril simple rounded pore; mouth relatively small, posterior margin of maxilla reaching vertical through anterior margin of orbit; lips fleshy with numerous minute papillae, anterior portion of lower jaw with dense cluster of minute papillae; mandible with 5 pairs of small pores; posterior margin of preopercle moderately serrated; upper portion of opercle with 2 flattened spines, lower spine longer than upper spine; posterior tip of cleithrum exposed, with serrated margin possessing 3 minute spinous points; posterior margin of posttemporal exposed, being semicircular bony crest, with serrated margin possessing 9 minute spinous points. Both jaws with narrow bands of ca. 5 rows of large pointed conical teeth in anterior portion, bands becoming narrower posteriorly, teeth on outermost row generally about twice length of teeth on inner rows, but not forming canines; teeth absent on vomer and palatine; tongue broad, rounded. Head and body, including snout, covered with ctenoid scales, but maxilla, around nostrils, pectoral axilla, and branchiostegal membrane naked; ventral surface of lower jaw covered with ctenoid scales, small patch of few poorly developed ctenoid scales between two posteriormost mandibular pores; dorsal, anal, pectoral, and caudal fins with high scaly sheath. Dorsal-fin origin above upper origin of pectoral-fin base, with single notch between spinous and soft-rayed portions; spines robust, first spine shortest, fourth spine longest; membrane of spinous portion deeply incised; all soft rays branched, soft-rayed portion with rounded contour. Anal-fin origin below first dorsal-fin soft ray base; first spine short, second spine very robust, longest, clearly longer than third spine (second spine length in 1.8 times longer than third spine); soft rays all branched, contour of soft-rayed portion somewhat angular posteriorly. Pectoral fin pointed, posterior tip of longest ray reaching vertical through last dorsal-fin spine base. Pelvic-fin spine robust, first soft ray long, filamentous, its tip just reaching first analfin spine base when depressed. Caudal fin rounded.

Fresh coloration ( Fig. 3 View Fig ). Head and body dark silvery-grey, paler ventrally. Iris dull yellow. Three broad, oblique, longitudinal bronze stripes on side of body; uppermost stripe from nape (close to dorsal-fin origin) to upper caudal-fin base, through base of dorsal-fin soft-rayed portion and dorsal surface of caudal peduncle; middle stripe from nape to mid caudal-fin base; lowermost stripe indistinct from snout, across lower orbit and opercle to lower caudal-fin base, broadest above anal-fin base; stripes broadly intercon- nected near level with end of dorsal-fin base and narrowly at caudal-fin base. Dorsal fin dark brownish, membrane between eighth spine and first soft ray tinged with black. Anal fin dark brownish. Pectoral fin pale brownish. Pelvic fin dark brownish, paler basally. Caudal fin pale grey, somewhat dusky distally. In preserved condition, coloration become darker; dark markings clearly retained.

Remarks. The present specimen matches well the original description and figure of H. bengalensis given by Mohapatra et al. (2013) in having the following diagnostic characters: anterior portion of lower jaw with dense cluster of numerous short papillae; 10 mandibular pores; 3 longitudinal stripes on side of body; first pelvic-fin soft ray filamentous, extremely long, its tip reaching the first anal fin spine base when depressed; and 7 scale rows above lateral line, 19 below lateral line. Although the present specimen differed slightly from the original description of H. bengalensis in having a fewer number of anal-fin soft rays, a greater number of gill rakers, and slightly greater body width and snout length ( Table 2), these most likely represent intraspecific variations. Such variations especially for the body proportion are possibly represented size-related differences, since the present specimen (122.8 mm SL) is clearly larger than previously known specimens (45.6–87.4 mm SL).

Hapalogenys bengalensis is characterized in having three broad, oblique, longitudinal stripes on the side of the body ( Figs 3 View Fig , 4), distinguishing the species from the following members of the Hapalogenys kishinouyei complex, defined by having two to five longitudinal stripes on the body: Hapalogenys kishinouyei Smith and Pope, 1906 (five stripes), H. dampieriensis Iwatsuki and Russell, 2006 (four), and H. filamentosus Iwatsuki and Russell, 2006 (two) ( Iwatsuki and Russell 2006; Mohapatra et al. 2013). Another congener, H. merguiensis , co-occurring with H. bengalensis in the Andaman Sea, is readily distinguished from the latter by having two oblique bands on the side of the body ( Iwatsuki et al. 2000; Iwatsuki and Russell 2006; Fig. 4).

Hapalogenys bengalensis , originally described by Mohapatra et al. (2013) on the basis of 14 specimens collected off West Bengal, India, in the northern Bay of Bengal ( Fig. 2 View Fig ), has not been recorded since the original description . The present specimen being the first record of the species from the Andaman Sea, in addition to being the largest known sample of the species at 122.8 mm SL.