DESCRIPTIONS OF THE LARVAE OF STICHASTER AUSTRALIS (VERRILL) AND COSCINASTERIAS CALAMARIA (GRAY) (ECHINODERMATA: ASTEROIDEA) FROM NEW ZEALAND, OBTAINED FROM LABORATORY CULTURE

Abstract

1. Methods for the laboratory rearing of larvae of the starfishes Stichaster australis and Coscinasterias calamaria are described. 2. Larval development in S. australis and C. calamaria is very similar, although C. calamaria has a slightly faster rate of development. Fertilized eggs develop through a bipinnaria to a brachiolaria stage. Late brachiolaria larvae were present 38 days after fertilization in S. australis and 27 days after fertilization in C. calamaria. 3. As in the development of the feeding larvae, the process of metamorphosis is very similar in S. australis and C. calamaria. The time from attachment to the substratum by the late brachiolaria larvae to the completion of metamorphosis of the juvenile starfish is 6-7 days in S. australis and 6 days in C. calamaria. 4. Unfavorable culture conditions may have been the cause of abnormal larvae found in some cultures. 5. Larval development of S. australis and C. calamaria resembles closely that of other starfish species with indirect development, especially Asterias rubens. This may reflect the close taxonomic affinities of these three species.