Isozoanthus antumbrosus, a new species of zoanthid (Cnidaria: Anthozoa: Zoanthidea) symbiotic with Hydrozoa from the Caribbean, with a key to hydroid and sponge-symbiotic zoanthid species

Abstract

Isozoanthus antumbrous, a new species of zooxanthellate zoanthid, is described. Colonies associate with the arborescent hydroid Dentitheca dendritica in the Caribbean Sea at 1-60 m. The coenenchyme, column, and oral disk are seal brown. The tentacles are golden brown and number 30-38. The coloration of the oral disk and tentacles recalls an annular solar eclipse. Polyps are 4.1-8.9 mm long and 2.2-4.3 mm in diameter. Genetic, morphological, and ecological characters differentiate this species from other hydroid-symbiotic zoanthids. Assignment to the genus Isozoanthus is based on morphology, with the acknowledgment that the currently accepted genera may not reflect evolutionary relationships. © 2009 Magnolia Press.