Revista Chilena de Historia Natural (Mar 2002)
Biología de la raya Psammobatis extenta (Garman, 1913) (Batoidea: Rajidae) Biology of the skate Psammobatis extenta (Garman, 1913) (Batoidea: Rajidae)
Abstract
Psammobatis extenta es un miembro común de la fauna de rayas de las costas de Sudamérica y su biología ha sido poco estudiada. Se investigaron aspectos de la biología de P. extenta a partir de datos obtenidos del descarte de arrastres comerciales de la flota pesquera de Puerto Quequén, Argentina, en febrero de 2000. La talla máxima alcanzada por las hembras fue 313 mm L T y 295 mm L T, por los machos. Las proporciones que presentaron menor variación y relación isométrica fueron: distancia narina-boca, distancia interorbital, longitud ojo+espiráculo, largo de disco y ancho de disco. La relación L T-Peso total presentó diferencias significativas (P Psammobatis extenta is a common off-shore member of the South American skate fauna and its biology is poorly known. Aspects of the biology of P. extenta were investigated using data collected from bycatch of commercial trawls in February 2000 off the coast of Puerto Quequén, Argentina. The maximum size attained by females was 313 mm T L and 295 mm T L, by males. Measurements that presented less variation and isometric relation were: nare to mouth length, distance between orbits, orbit and spiracle length, disc length and disc width. There were significant differences (P < 0.05) in the T L -Total weight relation between females and males, the former attaining a greater weight for the same T L. Males reach maturity between 260 and 266 mm in length, about 89 % of their maximum size. Females reach maturity at a length of 236-255 mm, about 79 % of their maximum size. Gravid females (13 % of the mature females) presented one egg case per oviduct (single oviparity). There is sexual dimorphism in dentition and alar spines: mature males have pointed conical cusps and possess alar spines along the outer margins of the upper disc, whereas female and immature males have grinding blunt teeth
