Abstract
A new species of Barathronus (Ophidiiformes: Aphyonidae) is described from a single, mature male specimen (101 mm SL) bottom trawled on the continental slope of Rio Grande do Norte, northeastern Brazil, between 1,964 and 2,045 m depth. The new species is diagnosed among congeners by the following combination of characters: peritoneum transparent, deep-set eyes not visible, eight fangs on vomer, anal fin rays 69, predorsal length 42.0% SL, preanal length 49.5% SL, penis long, slender, and lacking a pair of lobes at its base, and presence of a ventral flexure of the anterior 2-3 vertebrae. Additionally, morphological data of three specimens of Barathronus bicolor collected in Brazilian waters are presented and compared with those from 51 specimens from the western Central Atlantic.
Highlights
The Aphyonidae (Ophidiiformes) is composed of six genera and 22 valid species of mostly small to mediumsized, viviparous, bathypelagic and benthopelagic fishes
The only significant difference between examined characters occurs in the penis length, which measures about 4% SL in the only fully mature male collected off southeastern Brazil (NPM 1243), vs. 10-14% SL in specimens from the western Central Atlantic. Records from both the north and south hemispheres show that B. bicolor is widely distributed in the western Atlantic, a disjunctive distribution cannot be ruled out given that the species has not been recorded in the South Atlantic north of Rio de Janeiro State
It seems reasonable to suppose that B. bicolor occurs off northeastern Brazil, and that the distributions of B. linsi and B. bicolor probably overlap partially
Summary
The Aphyonidae (Ophidiiformes) is composed of six genera and 22 valid species of mostly small to mediumsized, viviparous, bathypelagic and benthopelagic fishes. Diagnostic features of the family include a loose, transparent and gelatinous skin, poorly developed (or not visible) eyes, basibranchial tooth patches absent, and long dorsal and anal fins joined to the caudal fin (Nielsen et al, 1999). Four species of Barathronus are reported from the Atlantic Ocean: B. bicolor in the West Atlantic from off South Carolina to off Rio de Janeiro State; B. multidens Nielsen, 1984 from off Florida and Morocco; B. unicolor Nielsen, 1984 from the western North Atlantic (38°28’N, 70°52’W); B. parfaiti (Vaillant, 1888) from between the Azores and France. Nielsen (1969: 53) listed two specimens of B. parfaiti, the holotype (MNHN 86-554) and a 100mm SL specimen collected in the Azores in 1896 (MOM, uncatalogued). Six species of Barathronus are reported from the Indian and Pacific oceans: B. affinis Brauer, 1906, from off the Maldive Islands, Indian Ocean; B. bruuni Nielsen, 1969, from the western South Indian Ocean; B. diaphanus Brauer, 1906 and B. maculatus Shcherbachev, 1976, both from the Indian and
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