Notes on the morphology, distribution and bionomics of Phyllodiscus semoni (Anthozoa: Actiniaria: Aliciidae)

Abstract

Phyllodiscus semoni Kwietniewski, 1897, a little-known species of sea anemones of the family Aliciidae, is quite widely distributed in the tropics but has not been recorded from the Spratly Islands so far. The reason that the range of this species is poorly studied lies not only in the fact that many tropical areas are still poorly explored but also in the peculiar appearance of this animal in the sea. It rarely extends its tentacles during daylight hours and is not readily recognised by divers and researchers as an actinian. Our underwater observations, accompanied by high-resolution photography and specimen collection, evidence the presence of this species along the continental coast of Vietnam and in the waters of the Spratly Archipelago. During the dives, some observations were made on the behavior of the polyps and symbiotic shrimp living on their bodies. This species of sea anemones can cause severe skin burns in humans, which is confirmed by our experience. Summarised literature data on the distribution of Ph. semoni is provided.