The wentletrap Epitonium hartogi spec. nov. (Gastropoda: Epitoniidae), associated with bubble coral species, Plerogyra spec. (Scleractinia: Euphyllidae), off Indonesia and Thailand

This is the first record of an association between a wentletrap species (Gastropoda: Epitoniidae) and coral species of the Euphyllidae (Scleractinia), i.e. Plerogyra simplex and P. diabolotus. While describing Epitonium hartogi spec. nov., special attention is given to the ontogenetic development within the eggcapsules, the structure and microsculpture of the opercula, the radulae, and the microsculpture on the radular jaws. These characters proved to be at least partly diagnostic in the epitoniid species Epitonium albidum, E. billeeanum, E. costulatum, E. hoeksemai, E. ingridae, E. lochi, E. millecostatum, E. pyramidalis, E. twilae, E. ulu and Nitidiscala tincta. Spiculae-like crystals covering the epitoniid egg-capsules are described; such crystals are also present within the tentacles of the Plerogyra host.