Comprehensive DescriptionRead full entry
DescriptionAn intertidal barnacle with six coarsely ridged wall plates, a kite-shaped opercular opening, and a membranous base. The rostral plate is relatively narrow and plates are of roughly equal size. The rostral plate is not fused with rostrolaterals. The tissue inside the opercular aperture is blue (paler than in Chthamalus stellatus) with brown and black markings. Usually conical in shape, however when crowded may become tubular. It reaches a maximum diameter of approximately 14 mm, depending on habitat, food availability and level on shore.Before 1976 Chthamalus montagui was considered a variety of Chthamalus stellatus, but in 1976 was identified as a distinct species due to differences in its vertical zonation on the shore and morphology, particularly in the shape of the opercular plates, setation of the smaller cirri, the more sheltered locations in which it was found and its different pattern of zonation (Southward, 1976).