Cantellius cardenae spec. nov. (Cirripedia: Pyrgomatinae) from Acropora (Isopora) brueggemanni (Brook, 1893) (Anthozoa: Acroporidae), a case of host specificity in a generalist genus

A new species of coral inhabiting barnacle Cantellius cardenae spec. nov. (Crustacea, Cirripedia: Pyrgomatinae) is described. This barnacle was found on the staghorn coral Acropora (Isopora) brueggemanni (Scleractinia: Acroporidae). It is characterized by having transversally elongated scuta and narrow terga with a spur length more than half of the total tergal length. This species belongs to the secundus group of Cantellius, which includes barnacles with transversally elongated scuta, and which are limited to the Acroporidae. The distribution of C. cardenae supports the hypothesis that structurally specialized pyrgomatines occupy a more limited variety of hosts than do morphologicaly generalized ones.