Barathronus roulei

description

Description. Body compressed with caudal part rather short and loose, transparent skin. Origin of dorsal fin at midpoint of fish and anal fin origin well behind midpoint. Tip of pectorals end halfway to anus and pectoral peduncle as high as long. Pelvic fins end below middle of pectoral fin. Head broad and high with an almost vertical mouth-cleft. Eyes indistinct consisting of a subcircular, dark ring (4 mm in diameter) with a small (0.5 mm) centrally placed and deeper situated dark spot. Nostrils with a low rim placed close together midway between upper lip and eyes. Anterior gill arch with one short and five long rakers on upper branch, one long raker in the angle, and lower branch with 20 long and two short rakers. Gill filaments about 50. Pseudobranch with 2 – 3 filaments. Histological examination of the gonads showed many spermatocytes and no spermatozoa indicating an unripe male, which corresponds well with the only 1 mm long penis placed in a thick-walled urogenital hood. Otoliths dissolved. Sensory papillae. All very small with 12 – 14 papillae in lateral midline on caudal part; from about anus it forks into a dorsal and ventral branch the latter with 8 – 10 papillae which

Revision of the circumglobal genus Barathronus (Ophidiiformes, Bythitidae) with a new species from the eastern North Atlantic Ocean

diagnosis

Diagnosis. Barathronus roulei differs from the other five Barathronus species with a pigmented peritoneum by the following combination of characters: dorsal-fin rays 71, anal-fin rays 66, precaudal vertebrae 34, total vertebrae 82, origin of dorsal fin above vertebra 29, anterior gill arch with 26 long rakers, peritoneum dark, paired bulbs at basis of penis not developed, no ventral flexure of anteriormost vertebrae and vomer with one fang in each side and 2 – 3 small, pointed teeth in between.

Revision of the circumglobal genus Barathronus (Ophidiiformes, Bythitidae) with a new species from the eastern North Atlantic Ocean

distribution

Distribution (Fig. 1). Trawled on a depth of 1846 meters off the Azores. Ethymology. Named after the French ichthyologist, Louis Roule.

Revision of the circumglobal genus Barathronus (Ophidiiformes, Bythitidae) with a new species from the eastern North Atlantic Ocean

materials_examined

Material examined (1 specimen, SL 100 mm). Holotype: MOM POI- 0003655, SL 100 mm, male, Azores, 39 ° 11 ’ N, 30 ° 44 ’ 40 ’’ W, RV Princesse-Alice, st. 698, trawl, 1846 m, 18 July 1896.

Revision of the circumglobal genus Barathronus (Ophidiiformes, Bythitidae) with a new species from the eastern North Atlantic Ocean