Meeting Abstract

P2.35  Jan. 5  Reproduction of the Antarctic external brooder sea anemone Epiactis georgiana Carlgren, 1927 (Cnidaria: Anthozoa: Actiniaria) RODRIGUEZ, E*; LOPEZ-GONZALEZ, PJ; GILI, JM; Ohio State University, Columbus; Universidad de Sevilla; CMIMA-CSIC, Barcelona fani@us.es

The sea anemone genus Epiactis (Verrill, 1869) is known by its external parental care, an uncommon strategy among actiniarians. More than half of the species within Epiactis show external brooding of their offspring. Some reproductive aspects of the Antarctic sea anemone Epiactis georgiana Carlgren, 1927 have been studied. Data suggest that E. georgiana reproduces seasonally and is the third species of the genus to show hermaphroditism. At least two generations overlap at the same time in an adult; each generation takes up to two years to develop completely. Oogenesis starts in the early austral spring and there is internal fertilization. The release of the embryos/larvae probably occurs in the last months of the austral spring coinciding with phytoplankton bloom in late spring; released offspring are externally brooded on the distal part of the adult column until an advance developmental stage. Although interesting questions like the sexual or asexual origin of the offspring of Epiactis georgiana still have to be addressed, this study represents the first step for our understanding of the mating system of the species.