Reproduction and feeding ethology of a tropical,intertidal sand-dwelling anemone (Actinoporus elongatus,Carlgren, 1900)

Actinoporus elongatus is a widely distributed, tropical, intertidal anemone from the Indo-Pacific and Caribbean regions. Its recorded occurrences are disjunct and its feeding and reproductive ecology have not previously been described in detail. A population of this sand-dwelling species was studied for one year at Shelly Bay, Queensland, Australia. Individuals were found to be randomly distributed within the study site at a density of 42 anemones per hectare. No immigration, juvenile recruitment or mortality was observed. Histological analysis indicated a protracted period of gamete maturity during the summer months, and that the sex ratio was 1:1. A. elongatus is an opportunistic feeder with two distinct feeding methods — actinopharyngeal eversion and a newly described trapdoor response. Ciliary currents on the tentacular crown and oral disk were used mainly for cleaning and sand removal.Department of Zoology, James Cook University of North QueenslandDepartment of Marine Biology, James Cook University of North QueenslandDepartment of Marine Biology, James Cook University of North Queensland