Bathyraja cousseaui sp.n., a new softnose skate from the southwestern Atlantic

DÍAZ DE ASTARLOA, J. M; MABRAGAÑA, E.

Manaos, Brasil.

Congreso; 19th Annual Meeting of the American Elasmobranch Society; 2003

American Elasmobranch Society

A new species of the rajid genus Bathyraja Ishiyama is described from the southwestern Atlantic. The description was based on 20 specimens collected from off northern Patagonia and southern Malvinas Islands. Methods for making measurements and counts followed standard procedures. One mature male and one mature female were dissected in order to examine the skeletal structures (neurocranium, scapulocoracoids and claspers). The specimens exhibit a rhomboidshaped disc, its length 0.5 times in total length. Preorbital length 2.41 - 2.93 times interorbital distance. A large and more distinct round pale area ocellus-like, margined with dark brown on posterior part of each pectoral base of the upper side of disc. Lower surface of the disc largely creamy- white, with posterior margins of pectoral fins, and edges of posterior lobes of pelvic fins narrowly edged dusky brown. Underside of tail almost entirely dark-brown. Upper surface of disc completly covered with numerous small spinules, also placed on interorbital area, tail, dorsal fins and posterior pelvic lobes. No ocular thorns. A row of 7 to 9 strong thorns in a median dorsal line (two of them set on the nuchal and 1 to 2 thorns on the suprascapular regions). No gap between nuchal-suprascapular and the anterior median thorns. Tail with 16 to 18 strong midrow thorns extending from axil of pelvic fins to the first dorsal fin. Males with elongated, slender rod-shaped claspers. Dorsal fins densely spinulose, close to the end of tail and with no space between them. Ventral surface of disc, pelvics, claspers and tail without of dermal denticles. Besides the external morphological features, skeletal characteristics are also analysed, and are compared with those of other congeneric species. Bathyraja cousseaui n. sp. was named in honor of Prof. Dr. María Berta Cousseau who has been contributing greatly to the marine fishes of Argentina. Cousseau who has been contributing greatly to the marine fishes of Argentina. The description was based on 20 specimens collected from off northern Patagonia and southern Malvinas Islands. Methods for making measurements and counts followed standard procedures. One mature male and one mature female were dissected in order to examine the skeletal structures (neurocranium, scapulocoracoids and claspers). The specimens exhibit a rhomboidshaped disc, its length 0.5 times in total length. Preorbital length 2.41 - 2.93 times interorbital distance. A large and more distinct round pale area ocellus-like, margined with dark brown on posterior part of each pectoral base of the upper side of disc. Lower surface of the disc largely creamy- white, with posterior margins of pectoral fins, and edges of posterior lobes of pelvic fins narrowly edged dusky brown. Underside of tail almost entirely dark-brown. Upper surface of disc completly covered with numerous small spinules, also placed on interorbital area, tail, dorsal fins and posterior pelvic lobes. No ocular thorns. A row of 7 to 9 strong thorns in a median dorsal line (two of them set on the nuchal and 1 to 2 thorns on the suprascapular regions). No gap between nuchal-suprascapular and the anterior median thorns. Tail with 16 to 18 strong midrow thorns extending from axil of pelvic fins to the first dorsal fin. Males with elongated, slender rod-shaped claspers. Dorsal fins densely spinulose, close to the end of tail and with no space between them. Ventral surface of disc, pelvics, claspers and tail without of dermal denticles. Besides the external morphological features, skeletal characteristics are also analysed, and are compared with those of other congeneric species. Bathyraja cousseaui n. sp. was named in honor of Prof. Dr. María Berta Cousseau who has been contributing greatly to the marine fishes of Argentina. Cousseau who has been contributing greatly to the marine fishes of Argentina. Bathyraja Ishiyama is described from the southwestern Atlantic. The description was based on 20 specimens collected from off northern Patagonia and southern Malvinas Islands. Methods for making measurements and counts followed standard procedures. One mature male and one mature female were dissected in order to examine the skeletal structures (neurocranium, scapulocoracoids and claspers). The specimens exhibit a rhomboidshaped disc, its length 0.5 times in total length. Preorbital length 2.41 - 2.93 times interorbital distance. A large and more distinct round pale area ocellus-like, margined with dark brown on posterior part of each pectoral base of the upper side of disc. Lower surface of the disc largely creamy- white, with posterior margins of pectoral fins, and edges of posterior lobes of pelvic fins narrowly edged dusky brown. Underside of tail almost entirely dark-brown. Upper surface of disc completly covered with numerous small spinules, also placed on interorbital area, tail, dorsal fins and posterior pelvic lobes. No ocular thorns. A row of 7 to 9 strong thorns in a median dorsal line (two of them set on the nuchal and 1 to 2 thorns on the suprascapular regions). No gap between nuchal-suprascapular and the anterior median thorns. Tail with 16 to 18 strong midrow thorns extending from axil of pelvic fins to the first dorsal fin. Males with elongated, slender rod-shaped claspers. Dorsal fins densely spinulose, close to the end of tail and with no space between them. Ventral surface of disc, pelvics, claspers and tail without of dermal denticles. Besides the external morphological features, skeletal characteristics are also analysed, and are compared with those of other congeneric species. Bathyraja cousseaui n. sp. was named in honor of Prof. Dr. María Berta Cousseau who has been contributing greatly to the marine fishes of Argentina. Cousseau who has been contributing greatly to the marine fishes of Argentina. Bathyraja cousseaui n. sp. was named in honor of Prof. Dr. María Berta Cousseau who has been contributing greatly to the marine fishes of Argentina.