Decapterus macrosoma Bleeker, 1851

Ray, Dipanjan, Mishra, Subhrendu S., Mohapatra, Anil & Ghorai, Narayan, 2021, Notes on Carangids (Carangiformes: Carangidae) from West Bengal Coast with new records, Records of the Zoological Survey of India 121 (4), pp. 511-520 : 514

Decapterus macrosoma Bleeker, 1851 : Short fin scad ( Figure 3 )

1851. Decapterus macrosoma Bleeker, Natuurk. Tijdschr. Ned. - Indie, 1 (4): 358 (type locality: Jakarta, Java, Indonesia) .

Diagnosis: D VIII, I + 34–35 + 1 (finlet); A II, I+ 29–30 + 1 (finlet); P 20–21; V I, 5; GR (9–10) + (35–37). Body depth 6.5–6.7 in SL; HL 3.7–3.9 in SL; eye diameter 4.1–

4.4 in HL. Body nearly rounded, not distinctly laterally compressed. Adipose eyelid well developed. Posterior end of upper jaw concave dorsally and rounded below. Lateral line slightly curved, curved portion longer than straight part, becoming straight below 15 th soft dorsal ray; straight part of lateral line with 18-24 scales and 29–32 scutes, height of largest scute less than eye diameter. Shoulder girdle margin is with two papillae. Dorsal and anal fin with a terminal detached finlet. Colour: Dorsal part bluish green, silvery below; fins light yellow; tongue whitish. Distribution: Indo-Pacific and Southeast Atlantic: Knysna to Natal, South Africa to Persian Gulf and the Red Sea, east to Hawaiian Islands, north to Japan, south to Australia, New Caledonia, Tonga; eastern Pacific from Galapagos Islands to Gulf of California and Peru ( Fricke et al., 2020). From Indian coast this species was reported from Andhra Pradesh, Kerala, Karnataka, Tamil Nadu ( Joshi et al., 2011), Maharashtra ( Barman et al., 2012), Gujarat ( Barman et al., 2000) and Andaman and Nicobar Islands ( Rajan & Mishra, 2020).

Remarks: Decapterus macrosoma is herewith reported for the first time from West Bengal. This species can be distinguished from its congeners in having posterior end of upper jaw concave above (vs straight in all congeners) and straight part of lateral line with 14 to 29 scales (vs 0 to 15 scales in other congeners) ( Smith-Vaniz, 1999). The other species in the genus Decapterus reported from West Bengal coast is D. russelli (Rüppell, 1830) . Apart from the upper jaw character stated above, D. russelli differs in having lesser scales (0-4) on straight part of lateral line, and longer pectoral fin, that extending to level of second dorsal fin origin (fin length 76-97% of HL vs 61-75% of HL in D. macrosoma , i.e., not reaching to level of second dorsal fin origin) ( Smith-Vaniz, 1999).

Figures

Figure 3. Decapterus macrosoma Bleeker, 1851.