Decapterus smithvanizi Kimura, Katahira et Kuriiwa, 2013

Delloro, Emmanuel S. Jr., Babaran, Ricardo P., Gaje, Arnold C., Cambronero, Pearlyn T., Alama, Ulysses B. & Motomura, Hiroyuki, 2021, First record of slender red scad, Decapterus smithvanizi (Actinopterygii: Perciformes: Carangidae), from the Philippines, Acta Ichthyologica et Piscatoria 51 (3), pp. 233-239 : 233

publication ID	https://dx.doi.org/10.3897/aiep.51.63117
publication LSID	lsid:zoobank.org:pub:2C7167EE-6DF7-4B2B-B7BC-D48BC3726D42
persistent identifier	https://treatment.plazi.org/id/C818B1A0-6C36-5256-97D3-95056E3327F7
treatment provided by	Acta Ichthyologica et Piscatoria by Pensoft
scientific name	Decapterus smithvanizi Kimura, Katahira et Kuriiwa, 2013
status

Treatment

Material examined.

Decapterus smithvanizi : UPVMI 3059 through 3068, 10 specimens, 187.3-226.9 mm SL, Miagao Fish Market, Iloilo, Feb.-May 2020, E. Delloro and R. Babaran. Decapterus tabl : UPVMI 3069 through 3077, 10 specimens, 185.4-208.96 mm SL, Miagao Fish Market, Iloilo, May 2020, E. Delloro. Decapterus kurroides : 9 specimens, UPVMI 3078 through 3086, 166.7- 191.3 mm SL, Miagao Fish Market, Iloilo, Feb.-May 2020, E. Delloro and R. Babaran.

Description.

Body elongate, compressed, and comparatively slender, deepest between first dorsal and second dorsal fin. Dorsal and ventral profile body slightly convex from tip of snout to caudal-fin base. Mouth terminal, large; posterior tip of maxilla reaching vertical through anterior margin of eye; posterior tip of upper jaw not hooked. Interorbital space slightly convex, with scales. Predorsal scaly area extending to anterior margin of eye. Upper end of pectoral-fin base anterior to vertical through opercular margin; lower end of pectoral-fin base vertical through pelvic-fin origin. Pectoral fin asymmetrical, its posterior tip pointed, reaching beyond vertical through second dorsal-fin origin. Pelvic-fin origin anterior to vertical through dorsal-fin origin. First dorsal fin higher than second; single finlet present both dorsally and ventrally on caudal peduncle. Caudal fin forked; covered with small scales. Body scales small and ctenoid. Lateral line extends downwards from origin of second dorsal fin; running straight from middle of second dorsal fin to caudal-fin base; curved part longer than straight part, covered with ctenoid scales and scutes at posteriormost area; straight lateral line covered with scutes reaching beyond hypural bone. Head covered with scales, except snout area, mandible and anteroventral region of head; posteriormost end of scaly head region anterior to vertical through opercular margin; adipose eyelid developed. Teeth on jaws minute, two rows on upper jaw and single row on lower jaw. Lower jaw slightly protruding. Gill rakers slender, covered with spinules at inner surface.

Color when fresh. Head and body bluish to pale black dorsally, pale white to silvery ventrolaterally; black blotch present on upper edge of opercle; both margins of dorsal, caudal, and pectoral fins and finlet red with fine melanophores; anal fin, pelvic fins and ventral finlet pinkish to white with fine melanophores (Fig. 1A View Figure 1 ).

Color when preserved. Head and body greyish to brownish dorsolaterally, pale white ventrolaterally; black blotch present on upper edge of opercle; both margins of dorsal, caudal, and pectoral fins and finlet brownish to dirty white with fine melanophores; anal fin, pelvic fins, and ventral finlet brownish to white with fine melanophores (Fig. 2A-C View Figure 2 ).

Distribution.

Decapterus smithvanizi is distributed in the Andaman Sea, South China Sea, Indonesia, and the western coast of Thailand ( Kimura et al. 2013), Taiwan ( Smith-Vaniz et al. 2018b), Japan ( Iwatsubo et al. 2016; Hata and Motomura 2017), Myanmar ( Psomadakis et al. 2020), and Pakistan ( Psomadakis et al. 2015). Specimens were collected off Iloilo Province (Panay Island), Philippines. The specimens, used in this study, represent the first record from the Philippines.

Comparison.

Decapterus smithvanizi can be easily distinguished from the other members of red-fin Decapterus group in having fewer cycloid scales along the curved part of the lateral line (54-62), long pectoral fin (25.5%-29.6% SL) reaching beyond a vertical through the origin of second dorsal fin and fewer lower gill rakers (26-28) (Table 1 View Table 1 ). Melanophores scattered on the pectoral, pelvic and anal fin rays of D. smithvanizi (Fig. 2A-C View Figure 2 ) are more distinct than those of D. tabl (Fig. 2D-F View Figure 2 ) and D. kurroides (Fig. 2G-I View Figure 2 ). Two other species in red-fin Decapterus group, D. kurroides and D. tabl , are commonly caught together with D. smithvanizi in Panay Island. Similarities in morphological characters and coloration may lead to confusion and misidentification. However, they can be distinguished from each other with proper examination. In specimens of D. kurroides , the body depth is deeper (23.4%-26.6% SL) compared to D. tabl (18.4%-21.2% SL) and D. smithvanizi (19.7%-22.5% SL) (Fig. 3A View Figure 3 ; Table 1 View Table 1 ). The head length of D. kurroides (30.8%-31.7% SL) is longer than D. smithvanizi (29.3%- 31.0% SL) and D. tabl (29.0%-30.0% SL) (Fig. 3B View Figure 3 ; Table 1 View Table 1 ). The pectoral fins of D. smithvanizi (25.5%-29.6% SL) and D. kurroides (27.6%-32.8% SL) are longer than D. tabl (17.6%-20.5% SL) (Fig. 3C View Figure 3 ; Table 1 View Table 1 ). Additionally, it was observed that body scales of the specimens extend on to the head dorsally and formed a sideways “W-shaped” margin (Fig. 4 View Figure 4 ). The distance from the snout to the central posterior tip of the margin was measured. D. kurroides is longer in proportion to head length (91.0%-97.1% HL) compared to D. smithvanizi (85.0%-87.2% HL) and D. tabl (80.0%-87.4% HL) (Fig. 3D View Figure 3 ; Fig. 4 View Figure 4 ; Table 1 View Table 1 ).