ABSTRACT
Frequency and presumed causes of arm regeneration in Amphipholis squamata (Echinodermata: Ophiuroidea).
The intertidal population of Amphipholis squamata at Luc-sur-mer (Bay of Seine, France) was sampled monthly from May 1988 to May 1989. Of 2380 individuals, 60.6 % were regenerating one or more arms. Of 9260 arms, 31.8 % were regenerating that is ca. 1.2 regenerating arms per individual. Arm autotomy mostly occurs either in the middle or in the basal part of the arms. The number of the regenerating individuals increases in a regular fashion from June to November; the highest values were recorded for February. Due to the particular location of the individuals (under stones in the intertidal area), it is suggested that arm autotomy is more likely to result from the hydrodynamic conditions than predation.
