Suspected neoplasms in deep-sea corals (Scleractinia:Oculinidae:Madrepora spp.) reinterpreted as galls caused by Petrarca madreporae n. sp. (Crustacea:Ascothoracida:Petrarcidae)

Hypertrophied corallites with irregular septal patterns in the Hawaiian deep-water coral Madrepora kauaiensis Vaughan were interpreted 30 yr ago as poss~ble neoplasms, and this idea has persisted in comparative oncolog~cal literature. Many colonies of Madrepora oculata L. with sin~ilarly modified corallitc,~ are recorded herein from 233 to 604 m depth off northwestern Australia and Japan, In the Formosa Strdit, and in the Banda and Araiura Seas, Indonesia. The affected corallites have a hollow space bencdth the interrupted colu~nella. Most specimens had been dried and bleached, lcdving no t ~s s u e , but in some. alcohol-preserved Indonesian specimens this cavity was occup~ed by endoparasitic petrarc~d ascothoracidan crustaceans. These are described herein as Petrarca madreporae Grygier, new specles, w h ~c h 1s characterized by a posterior lobe on each carapace valve, poorly armed mouthparts, and a bifid penls with fixed raml. The validity of the diagnosis of the petrarcid genus Zlbrowia Grygier, 1985 is questioned. The abnormal corallites are provisionally reinterpreted as an unusual kind of petrarcid 'internal gall.