Physiculus indicus, Idrees Babu & Ho & Mariyambi & Sureshkumar, 2022

Idrees Babu, K. K., Ho, Hsaun-Ching, Mariyambi, P. C. & Sureshkumar, S., 2022, Two new species of the codling fish genus Physiculus from Lakshadweep, India (Gadiformes: Moridae), Zootaxa 5104 (1), pp. 111-124 : 112-115

Physiculus indicus sp. nov.

Common name: Indian Codling

Figs.1‒2 , Table 1

Holotype. MTRLDST 00214, 162 mm SL, 183 mm TL, India, Lakshadweep, East Coast of Kavaratti Island , 10°33’49.9”N, 72°39’4.0”E ,, ca. 350 m, 9 April 2018.

Paratypes. MTRLDST 00215, 128 mm SL, 148 mm TL; MTRLDST 00216, 143 mm SL, 169 mm TL; MTRLDST 00217, 154 mm SL, 169 mm TL; MTRLDST 00218, 142 mm SL, 162 mm TL; all collected with holotype.

Etymology. The specific is derived from the type locality, India.

Diagnosis. A species of Physiculus with light organ situated at about the middle of pelvic-fin base and anus; light organ small; anus rather forward in position, closer to the light organ; gular region smooth without scales. Physiculus indicus differs from nearest congeners, P. argyropastus , in the position of the anus, and the number of total vertebrae; P. roseus in having the light organ closer to the anus than the pelvic-fin base; P. rhodopinnis by fewer rays in the second dorsal fin and fewer anal-fin rays. Although similar to each other, P. indicus differs from P. lakshadeepa in having fewer gill rakers, more caudal vertebrae, more total vertebrae, and first dorsal fin not higher than the second (vs. first dorsal fin higher with first ray filamentous)

Description. The morphometric data given in Table 1 is for the holotype, followed by the range of measurements from the paratypes in parentheses, except when otherwise indicated. Body round elongated, compressed posteriorly; head moderately large, slightly depressed anteriorly; eye large, its diameter 22.2% (19.0‒25.8%) HL; interorbital space broad, it width 31.8% (26­.6­‒34.1%) HL; snout broad and rounded, length 19.9% (19.9‒28.4%) HL, protruding slightly beyond upper jaw; mouth large; teeth equally sized; vomerine and palatine toothless; barbel on chin much shorter than orbit diameter, its length 4.7% (3.2‒8.9%) HL.

Gill rakers on first gill arch small, varying from spinous tubercles to small clubs, spinous initially at tips and progressively more spinous towards the angle on the lower branch and spinous at tips on the upper branch; abdominal cavity reaching the 9th pterygiophore of the anal fin.

Scales small and deciduous, 96­ (90‒102) in longitudinal series; 7 (7‒8) scale rows between the base of the first dorsal fin and lateral line; scale cycloid, covered on head and body, except for branchiostegal membrane and gular region. Continuous tube of lateral line reaching 14th ray of the second dorsal fin and discontinuous tube of lateral line reaching caudal peduncle.

First dorsal fin higher than the second; a very small gap separating first from second dorsal fin; the origin of the first dorsal behind a vertical through pectoral fin base; the origin of the second dorsal fin at a vertical through 5th anal-fin ray; both dorsal fins not indented. The pectoral fin extends up to the 8th ray of the second dorsal fin. Pelvic fin slender, two outermost rays filamentous and extend to 3rd ray of the anal fin. Caudal fin truncate and well separated from second dorsal and anal fins. Caudal peduncle short, less than orbit diameter, its length 8.8% (8.4‒10.3%) HL.

Light organ moderately sized; externally prominent as a circular scale less fossa in advance of the anus; its diameter 11.4% (6­.4‒12.0%) InV-af. Distance from inter ventral line to anterior margin of light organ 22.6­% (18.6­‒ 29.0%) In V-af; distance from posterior margin of the light organ to anterior margin of anus 17.6­% (17.6­‒23.8%) In V-af; and distance from the inter-ventral line to anterior margin of anus 53.6­% (50.6­‒58.2%) InV-af.

Vertebrae: 12 (11‒12) precaudal, 40 (40‒41) caudal vertebrae, and 52 (52) in total.

Coloration. . When fresh, the head and body, pinkish tan; abdomen, silvery blue; branchiostegal membranes black; vertical fin membrane dark brown. Colour when preserved head and body light brown and abdomen silvery.

Distribution. Physiculus indicus is known from the type series collected off Kavaratti Island, Lakshadweep, India, at a depth of ca. 350 m.

Figures

FIGURE 1. Physiculus indicus sp. nov., holotype, MTRLDST 00214, fresh. A. Lateral view. B. Ventral view of abdomen, showing the localities of pelvic-fin base, light organ and anus. C. Radiograph.

FIGURE 2. Physiculus indicus sp. nov., paratype, MTRLDST 00215, preserved. A. Lateral view. B. Ventral view of abdomen. C. Radiograph..