Egg cases of Bathyraja cousseauae, a poorly known large softnose skate from the Southwest Atlantic Ocean

VAZQUEZ, D. M.; DELPIANI, S. M; DÍAZ DE ASTARLOA, J. M.; MABRAGAÑA E.

Joao Pessoa

Conferencia; Sharks International Conference; 2018

The Joined-fins skate Bathyraja cousseauae (Chondrichthyes:Arhynchobatidae) has recently beendescribed from the Southwestern Atlantic Ocean(SWA), and has also been recorded in the SoutheastPaci c. Currently, it is assessed as Near reatenedby the IUCN and crucial information about lifehistory and reproduction is scarce. e genus Bathyrajais represented in the SWA by 11 species, mostof them exploited as by-catch or target species. Sofar, egg cases of six species have been described.Here, we describe the egg case of B. cousseauae.A mature female bearing egg cases (total length:1210 mm; disc width: 810 mm) was caught in April2016 by bottom trawl at 54°14?2.4?S; 63°11?38.4?W,at 293 m depth. One egg case was found in eachuterus. irteen morphometric characteristics wererecorded. Egg cases were large, 127.8-128.2 mmtotal length (Lec, excluding horns), with maximumegg case width (Wmax) ~ 64 % of Lec. Lateral keelwas relatively wide, about 9.5% of Wmax. Anteriorapron was remarkably narrower (6.7?8.4 times)than posterior apron. Posterior horns were similarin size than the anterior ones. Anterior respiratorycanals were relatively large, slightly longer (1.4-1.7times) than posterior ones. Egg cases in fresh wereuniformly bright golden, totally covered by a denselayer of sticky woven-like bres. Surface had longitudinalstriations with abundant, sharp and tallprickles well arranged giving a velvety texture to thetouch. Prickles were smaller in the central zone andon posterior horns. Attachment bres were observedat the bases of both anterior and posterior horns. Anaccurate species-level identi cation of egg cases iscrucial for recognizing nursery grounds. e largestegg cases of bathyrajids from the SWA described sofar correspond to B. griseocauda and B. cousseauae. ey can be distinguished each other by their casesurface, being smooth to touch in the former skatespecies. The remaining species have smaller eggcases than the joined- ns skate.