Revista Chilena de Historia Natural 75 (1): 179-188, 2002
RESEARCH ARTICLE
Biology of the skate Psammobatis extenta (Garman, 1913) (Batoidea:
Rajidae)
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<sub>L</sub> and 295 mm T<sub>L</sub>, 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<sub>L</sub> –Total weight relation between females and
males, the former attaining a greater weight for the same T<sub>L</sub>. 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.
Key words:
Psammobatis, Rajidae, Puerto Quequén
