THE OCCURRENCE OF PONTONIA-PINNOPHYLAX (DECAPODA, NATANTIA, PONTONIINAE) IN PINNA-NOBILIS (MOLLUSCA, BIVALVIA, PINNIDAE) FROM THE MEDITERRANEAN

During the course of a survey into the distribution and growth of the fan mussels Pinna nobilis and Pinna rudis from the coastal waters of t he Spanish Mediterranean the presence within the mussels of Pontonia p innophylax has been recorded. Pontonia pinnophylax typically occurred in adult pairs, but occasionally solitary male individuals were found. The width of the cephalothorax is greater in females than males, wher eas the chelae of the second periopods, which are unequal, are larger in males. There is a general relationship between the size of P. pinno phylax and its pinnid host; the largest individuals were found in the largest Pinna and vice versa.