Redescription of Alectona verticillata (Johnson) (Porifera, Alectonidae) boring into Japanese precious coral

Abstract The boring sponge Alectona (Nisella) verticillata (Johnson, 1899) was recorded, for the first time after the description, in a colony of Corallium elatius collected in the south of the Ryukyu Islands (Japan Sea). The material recorded allowed a redescription of the species based on the SEM analyses of its spicular complement. Alectona verticillata is the only species of the genus characterised by three kinds of amphiasters and by the lack of the large, spiny or tubercolate diactines, considered typical of the genus. Its distribution recalls the Tethyan distribution of the genus Corallium, indicating a high specificity of boring sponges for their substrata.