Observations on ecological adaptations of Lanceopora smeatoni (MacGillivray), West Island, South Australia

This paper reports on observations of the ecological adaptations of Lanceopora smeatoni (MacGillivray) occurring at Wes I Island, South Australia. At this location, L. smeatoni is found in 5 m water depth, ranges in size from 0.5 to 5 cm in width, and has a density of up to 240 specimens per/m 2 . An extra zoo idal attachment anchors the colony to the straw-like sheaths of the seagrass Posidonia sinuosa . Observations over a 2.5 year period show that L. smeatoni has an annual life cycle and a maximum growth rate of 0.3 mm/day. It is proposed that the annual life, cycle is an adaptation to the short life-span of P. sinuosa and rapid colonisation of other epizoans. The ecological benefits of the distinct discoid morphology and the extrazooidal attachment are also addressed.