Biology and Taxonomy of Encrusting Alcyoniid Soft Corals in the Northeastern Pacific Ocean with Descriptions of Two New Genera (Cnidaria, Anthozoa, Octocorallia)

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Biology (HMC)

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In this paper we summarize current knowledge of the distribution, ecology, and reproductive biology of 4 encrusting species in the soft coral family Alcyoniidae, with descriptions of 2 new genera and 2 new species. The new genus Discophyton is erected for Alcyonium rudyi, a species common in the lower intertidal of exposed rocky headlands from Vancouver Island, British Columbia, Canada south to Point Lobos, California, USA. Discophyton rudyi n. gen. & n. comb. propagates extensively by clonal fission, giving rise to characteristic aggregations of small, regularly spaced, disc-shaped colonies. We describe 2 new species and place them in a new genus, Thrombophyton. Thrombophyton coronatum n. gen. & n. sp. forms irregularly shaped, membranous colonies on rock surfaces; it occurs subtidally along the southern California coast from the Palos Verdes Peninsula to San Diego and on the California Islands. Thrombophyton trachydermum n. gen. & n. sp. has a similar, membranous growth form; it occurs both intertidally and subtidally on Vancouver Island, British Columbia, Canada, and in the San Juan Archipelago, Washington, and intertidally in central California, USA. Alcyonium pacificum, reported for the first time from North American waters, occurs in subtidal kelp beds around the Aleutian islands of Attu and Adak; its mushroom-shaped colonies are raised above the substrate on a short stalk. D. rudyi, T. trachydermum, and A. pacificum are all gonochores that reproduce in late summer; in contrast, T. coronatum appears to reproduce in the spring. D. rudyi and T. coronatum brood larvae internally to a late planula stage. A key to species is presented for all shallow-water soft corals known to occur in the northeastern Pacific Ocean.

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© 2003 American Microscopical Society, Inc