Reproduction, spawning, and development of 5 ophiuroids from Australia and New Zealand

. Reproduction and development in 5 brittle stars: Ophiactis resiliens, Ophionereis fasciata, Ophiothrix caespitosa, Ophiothrix spongicola , and Ophionereis schayeri were investigated in a series of laboratory spawning and fertilization trials. Ophiactis resiliens spawned in 90% of trials, both spontaneously (in response to disturbance) and after temperature and light shock. Ophiothrix caespitosa and Ophiothrix spongicola spawned in 100% of trials, largely due to spontaneous gamete release. In contrast, Ophionereis fasciata and Ophionereis schayeri spawned in only 32% and 50% of trials respectively, and only in response to temperature and light shock. All 5 species required an aggregation of males and females for spawning and fertilization. The breeding periods of each species, estimated from the spawning trials, are reported. Eggs of Ophiactis resiliens, Ophionereis fasciata, Ophiothrix caespitosa , and Ophiothrix spongicola were 83 μm, 99 μm, 105 μm, and 128 μm in diameter, respectively, and all underwent planktotrophic development through an ophiopluteus. Eggs of Ophionereis schayeri were 241 μm in diameter and underwent lecithotrophic development through an armless bilateral larva that secondarily transformed into a radial vitellaria. The two Ophionereis species, with differing modes of development, provide an ideal opportunity to examine life‐history evolution within a clade; however, these species were the most difficult to spawn. Ophiactis resiliens and the two Ophiothrix species spawned readily when they were visually mature at collection, and are thus useful species for developmental studies.