Rhinoptera jayakari Boulenger, 1895

Pradeep, Hosahalli Divakar, Swapnil, Shivdas Shirke, Nashad, Musaliyarakam, Venu, Sasidharan, Ranjan, Kumar Ravi, Sumitha, Gopalakrishnan, Devi, Sukham Monalisha & Farejiya, Mahesh Kumar, 2018, First record and DNA Barcoding of Oman cownose ray, Rhinoptera jayakari Boulenger, 1895 from Andaman Sea, India, Zoosystema 40 (4), pp. 67-74 : 69-71

Rhinoptera jayakari Boulenger, 1895

Rhinoptera jayakari Boulenger, 1895: 1520 -1523 .

MATERIAL EXAMINED. — MUS / FSI /PB/EB/09/2016, 1 ♂ Rhinoptera jayakari of Disc Width (DW) 494 mm and weight 2.9 kg ( Fig 2 A), collected from Junglighat fishing landing centre, Port Blair, South Andaman. The specimen was caught by a motorized fishing boat with longline gear at a depth of 30-50 m in the Andaman and Nicobar waters of the Andaman Sea.

DESCRIPTION OF SPECIMEN FROM THE ANDAMAN SEA

Disc length 1.5 in disc width; near straight anterior margin, posterior margin concave, apices acutely pointed ( Fig. 2);

disc mostly naked, except for small and stellate-based prickles dorsally on snout and inter orbital space ( Fig. 3B ); trunk thick and broad; head relatively broad and its width between posterior margin of spiracles 5.3 in disc width; upper part of the snout bilobed, separated almost at level of mouth from a lower, forward-projecting and also the bilobed part by a continuous deep groove around front of head; eyes moderately large, lateral on head and just anteromedial to spiracles ( Fig. 2B), eyes 1.8 in spiracle length; mouth transverse, straight, and narrow ( Fig. 3A ), preoral distance 8.4 in disc width; anterior nasal flaps long medially expanded and fused into a broad, elongated fringed nasal curtain overlapping mouth; nostrils slightly anterior to mouth, connected by broad nasoral grooves with mouth ( Fig. 3A ); tail short, 1.4 in disc length; base of tail with relatively high, rounded dorsal fin originating over pelvic-fin insertions; posterior margin of the dorsalfin almost upright; a serrate spine on tail behind dorsal fin ( Fig. 3D ), its base beneath dorsal-fin inner margin; teeth flat and pavement-like, in 9 series in upper jaw ( Fig. 3C ), 3 medial rows of broad teeth and 3-5 rows of narrower diamond-shaped teeth on each side.

Colour

Dorsal surface of disc dark olivaceous, ventral surface of disc white, tail dark olivaceous gradually becoming black distally.

DNA barcoding

The obtained partial sequence of COI gene of was submitted to the NCBI database with an accession number KY574494 .

FIG. 2. — A, Dorsal view of Rhinoptera jayakari Boulenger, 1895 ; B, antero-lateral view of the head with upper and lower lobes. Size of specimen: 494 mm DW.

The partial sequence of mitochondria COI gene produced a mean value of 623 nucleotide base pairs. BLAST result shows a 99 % match with the existing COI sequences of R. jayakari from India (GenBank: KF 899679.1, KF 899683.1, and KM 0703015.1) in the NCBI database. It also forms a distinctive clade in Neighbour Joining (NJ) phylogenetic tree inferred from mitochondrial COI gene sequences ( Fig. 4 ). The pair wise genetic distances values (K2P) based on COI sequences are given in Table 2 . The interspecies distance ranged from 0.002 to 0.008 and the genetic distance within the genus Rhinoptera ranged from 0.002 to 0.093.

Figures

FIG. 3. — Rhinoptera jayakari Boulenger, 1895: A, underside of the head; B, location of prickles on dorsal surface of the head; C, nine series of teeth, upper jaw; D, dorsal fin along with spine. Size of specimen: 494 mm DW.

FIG. 4. — Neighbour Joining (NJ) phylogenetic tree of Rhinoptera jayakari Boulenger, 1895 and related species inferred from mitochondrial COI gene sequences.