DISTRIBUTION AND REPRODUCTION OF INTERTIDAL SPECIES OF AQUILONASTRA AND CRYPTASTERINA (ASTERINIDAE) FROM ONE TREE REEF, SOUTHERN GREAT BARRIER REEF

摘要

The Asterinidae in tropical regions includes morphospecies complexes in the genera Aquilonastra and Cryptasterina. Cryptic species in these genera have been discovered based on differences in life histories and by attention to previously poorly investigated habitats. Two species with benthic development occur in the inter-tidal rubble habitat at One Tree Island, southern Great Barrier Reef. Aquilonastra byrneae (O'Loughlin and Rowe, 2006) has oral gonopores and is likely to lay benthic eggs masses. The presence of mature gonads in May and June indicates that egg masses should be present in winter. This species may be a protandric hermaphrodite. Cryptasterina sp. is an intragonadal brooder and may be conspecific with the coastal Cryptasterina hystera Dartnall and Byrne, 2003. This species broods its young to the juvenile stage in spring and summer. The juveniles emerge through aboral gonopores. Cryptasterina sp. is a simultaneous hermaphrodite. Aquilonastra byrneae and Cryptasterina sp. are distributed in the high shore rubble habitat at One Tree Reef in distinct bands at 1.5 m and 1.1 m above Lowest Astronomical Tide, respectively.