Sagartia troglodytes (PRICE, 1847) (Cnidaria: Sagartiidae) from the south-western Atlantic Ocean and the first evidence of spermatophores in sea anemones

Abstract

         Males and females of Sagartia troglodytes were found in Mar del Plata port (Argentina). This is the first record of S. troglodytes from the south-western Atlantic Ocean; so far this species was thought to be restricted to the European coasts of the North Atlantic Ocean and to the Mediterranean Sea. The female gonad shows the typical morphology of Actiniaria but the fertile mesenteries of the male bear peculiar structures, herein designated as spermatophores, each attached by a slender stalk. In laboratory-reared animals, the 265 - 468 µm long spermatophores were globular or nearly pyriform and were released through the mouth of the anemone by means of a rotatory motion. They contained spermatozoa gathered into spermatic cysts. This is the first description of such structures in Actiniaria; sperm release also differs from the basic scheme in sea anemones.