A new Congrid eel, Rhynchoconger smithi sp. nov. (Anguilliformes: Congridae), from the Bay of Bengal, India.

A new Conger eel species is described based on four specimens collected from Petuaghat fishing harbour, West Bengal, India. The combination of morphological characters and molecular data are discordant with the seven congeners currently recognized. Rhynchoconger smithi sp. nov. can be distinguished by having head smaller than trunk; pre-anal length more than three times in total length; a small eye, diameter 2.0-2.2 in snout length; rictus ending at a vertical through posterior margin of pupil; ethmovomerine teeth patch small, with 58-74 blunt teeth arranged in seven to eight irregular rows; vomerine teeth patch small, with 18-28 granular teeth arranged in four to six irregular rows, distinctly separated by narrow spaces from the ethmovomerine and maxillary teeth; three supraorbital pores and one supra-temporal pore; and 159+ to 164 total vertebrae. Moreover, R. smithi differs significantly from four congeners, R. nitens, R. flavus, R. ectenurus and R. gracilior, with Kimura two-parameter (K2P) distances 14.6%-20.3%.

Ariosoma indicum sp. nov., a new species of congrid eel (Anguilliformes: Congridae: Bathymyrinae) from the Indian waters.

Ariosoma indicum sp. nov. is described herein based on 12 specimens [(335-433 mm total length (TL)] collected off the Arabian Sea of southwest coast of India and 7 specimens from Digha Mohana, off the Bay of Bengal of northeast coast of India. The new species is distinguished from congeners in having the following combination of the characters: anus positioned anterior to middle of total length, pre-anal length 40.0%-43.1% of TL; short wedge-shaped pointed vomerine teeth patch, three or four rows in anterior portion, tapering posteriorly with four uniserial teeth; supraorbital canal with four or five pores; pre-dorsal vertebrae 9-10; pre-anal vertebrae 49-53; total vertebrae 141-146; body greenish-brown in colour; extremities of the lower jaw with minute dark pigmentation patches before the rictus, bicoloured pectoral fin. A. indicum shares few characters with the Indian water species, Ariosoma gnanadossi, but readily differs from the latter in having more pre-anal vertebrae (49-53 vs. 47 in A. gnanadossi); fewer lateral-line pores (130-137 vs. 145); shorter tail (54.9%-57.9% TL vs. 60.1% TL); smaller eye (15.1%-17.7% HL vs. 19.2% HL); smaller interorbital width (11.8%-15.7% HL vs. 18.2% HL); longer upper jaw (26.9%-30.2% HL vs. 19.2% HL). In addition, molecular analysis using partial mitochondrial COI gene suggests that A. indicum is genetically closer to Ariosoma maurostigma and Ariosoma melanospilos with a divergence of 15.0% and 15.8%, respectively, and forms a well-supported monophyletic clade.

A new congrid eel, Rhynchoconger randalli sp. nov. (Congridae: Anguilliformes), with a pentagonal pattern of vomer dentition from the Bay of Bengal, Indian waters.

A new species Rhynchoconger randalli sp. nov. is described herein on the basis of 2 specimens collected from Paradeep fishing harbor, Odisha, India along the Bay of Bengal from a depth of about 3640 meters. The pentagonal vomerine teeth pattern is unique among all the Rhynchoconger species described to date. The new species is characterized by predorsal vertebrae 78 and preanal vertebrae 2931. The new species closely resembles the recently described Rhynchoconger smithi, but differs in having a larger eye diameter (12.512.9% HL vs. 9.59.7% in R. smithi), smaller interorbital space (13.113.5% HL vs. 15.018.1 in R. smithi), lower dorsal-fin ray count before vent 4447 vs. 5458 in R. smithi, and unique pentagonal vomerine teeth pattern.

A new species of conger eel, Ariosoma (Congridae: Bathymyrinae), from the Bay of Bengal, India.

Ariosoma bengalense sp. nov. is described on the basis of two specimens having total length (TL) 216304 mm, collected from the northern part of the Bay of Bengal, India. The new species is characterized by the dorsal-fin origin positioned above the gill-opening margin and above the 9th lateral-line pores, supratemporal pore absent, 910 predorsal vertebrae; 4649 preanal vertebrae and 146149 total vertebrae. The new species most closely resembles the Indian species Ariosoma gnanadossi, the new species differs from A. gnanadossi having the snout length (SL) longer than eye diameter (snout length 1.42.0 in eye diameter) vs. snout length almost equal to the eye diameter in A. gnanadossi. Further, the new species has translucent pectoral fins vs. black pectoral fins in Ariosoma gnanadossi. The new species differs from four of the seven species reported from India: Ariosoma majus, A. melanospilos, A. maurostigma and A. indicum with absence of supratemporal pores vs. three in all the species mentioned.

First report of parasitic isopod Nerocila orbignyi (Cymothoidae) from India with its molecular characterization.

The present report provides the first material evidence of Nerocila orbignyi (Guérin-Méneville, 1832) collected from two different landing centres of the Chilika lagoon, thus claiming the first report of this parasite from India. One of the specimens was recorded from the host fish species Plotosus canius Hamilton 1822, constituting the first host record for this isopod. A key for the identification of N. orbignyi among its congeners is also provided. Molecular characterization of Cytochrome C Oxidase I (COI) gene of N. orbignyi was based on one specimen submitted for the first time to the NCBI database. This parasite is differentiated from the other available sequences of its related congeners retrieved from the NCBI and BOLD database by 26-34% in the Kimura 2 Parameter (K2P) distance and belongs to a separate cluster in Maximum likelihood (ML) tree analysis.