Bathyraja cousseauae sp.n.: A New Softnose Skate from the Southwestern Atlantic (Rajiformes, Rajidae)
A new species of softnose skate, Bathyraja cousseauae, is described from two adult and 19 juvenile specimens collected from different localities of the southwestern Atlantic. Bathyraja cousseauae is distinguished from all other southwestern Atlantic softnose skate species by its color pattern, squamation pattern of dorsal surface, lack of interspace between dorsal fins, and clasper morphology. The new species has a round pale area ocellus-like, margined with dark brown on posterior part of each pectoral base of dorsal surface, paler and dark spots over the disk, a continuous row of 21–27 median thorns from nuchal region to first dorsal fin and upper side of disc densely covered with dermal denticles. Males have rod-shaped claspers not expanded at proximal section of glans as it does in Bathyraja brachyurops. Besides the external morphological features, skeletal characteristics (neurocranium, scapulocoracoids, and claspers) are also described and illustrated here. Una nueva especie de raya de hocico blando, Bathyraja cousseauae, es descripta sobre la base de dos ejemplares adultos y 19 ejemplares juveniles capturados en diferentes localidades del Atlántico suroccidental. Bathyraja cousseauae se distingue de otras especies de rayas de hocico blando del Atlántico suroccidental por su patrón de coloración, patrón de espinulación de la superficie dorsal, ausencia de espacio entre las aletas dorsales y por la morfología del clásper. La nueva especie presenta una mancha pálida ocelar rodeada de un anillo marrón oscuro en la parte posterior de la base de cada aleta pectoral en la superficie dorsal, manchas pálidas y oscuras dispersas sobre el disco, una hilera continua de 21 a 27 espinas mediales desde la región nucal a la primera aleta dorsal y el lado superior del disco densamente cubierto de dentículos dérmicos. Los machos presentan cláspers en forma de vara no expandidos en la región proximal como sí ocurre en Bathyaraja brachyurops. Además de los aspectos morfológicos, también se describen e ilustran las características osteológicas (neurocráneo, escápulocoracoides y cláspers).Abstract
Resumen
Bathyraja cousseauae new species, holotype, INIDEP 719, 617 mm TL, juvenile male, off northern Patagonian continental shelf, Argentina. Scale bar = 5 mm
Neurocranium of Bathyraja cousseauae, n. sp. (paratype, INIDEP 720, juvenile male, 550 mm TL) in dorsal (A), ventral (B), and lateral (C) views. Figure abbreviations: ac = anterior cerebral vein foramen; af = anterior fontanelle; es = efferent spiracular artery foramen; ic = internal carotid artery foramen; into = interorbital vein foramen; nc = nasal capsule; of = orbital fissure; onc = orbitonasal canal foramen; os = optic stalk; pf = posterior fontanelle; poc = preorbital canal foramen; rb = rostral base; rs = rostral shaft; II = optic nerve foramen; III = oculomotor nerve foramen; VII = hyomandibular branch of facial nerve foramen. Scale bar = 10 mm
Lateral view of left scapulocoracoids of a female (A) and a male (B) specimens of Bathyraja cousseauae n. sp. (paratypes, INIDEP 720, juvenile female, 750 mm TL, and juvenile male, 550 mm TL, respectively). Figure abbreviations: ab = anterior bridge; adf = anterodorsal fenestra; avf = anteroventral fenestra; msc = mesocondyle; mtc = metacondyle; pdf = postdorsal foramina; prc = precondyle; pvf = postventral foramina; rc = rear corner; scp = scapular process. Scale bar = 10 mm
Right clasper cartilages of Bathyraja cousseauae, n. sp. (paratype, INIDEP 720, adult male, 695 mm DW) in external (A), dorsal (B and C) and ventral views (D and E). Figure abbreviations: aT2 = accesory terminal 2; Ax = axial; dM = dorsal marginal; cf = cleft; dT1 = dorsal terminal 1; dT2 = dorsal terminal 2; dT3 = dorsal terminal 3; pj = projection; pr = pseudorhipidion; ps = pseudosiphon; se = sentina; sp = spike; vM = ventral marginal; vT = ventral terminal.Scale bar = 10 mm
Dorsal view of left claspers of Bathyraja cousseauae, n. sp. (A) (holotype, INIDEP 719, 617 mm TL, juvenile male) and Bathyraja brachyurops (B). Arrow indicates lateral process. Scale bar = 10 mm
Geographic distribution of Bathyraja cousseauae based on material collected. Symbols represent more than one capture. Square indicates original locality of holotype
Contributor Notes
(JMDA) Departamento de Ciencias Marinas, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata. Funes 3350, B7602AYL Mar del Plata, Argentina. Consejo Nacional de Investigaciones Científicas y TÉcnicas (CONICET); and (EM) Museo del Mar, Av. ColÓn 1114, Mar del Plata, Argentina. (JMDA) astarloa@mdp.edu.ar Send reprint requests to JMDA.