Cirripedes from the middle Pleistocene Atsumi Group, Japan, with a reevaluation of the genus Adna Sowerby, 1823 (Balanoidea: Pyrgomatidae)

Abstract

Barnacles (Cirripedia, Thoracica) from the middle Pleistocene Atsumi Group, deposited in the Mizunami Fossil Museum, are classified. Sixteen species in 13 genera of barnacles are recorded and illustrated. Platylepas hexastylos (Fabricius) (Platylepadidae) and three archaeobalanids, Acasta sulcata Lamarck, Euacasta dofleini (Krüger), and Pectinoacasta pectinipes (Pilsbry), are first reported from the Pleistocene of Japan. Adna Sowerby, a coral-inhabiting barnacle genus of Pyrgomatidae, is reevaluated. As a result, Pyrgomina Bałuk and Radwański is synonymized with Adna, and A. anglica (Sowerby), a sole included species of the genus becomes a senior synonym of Pyrgomina djanae Ross and Pitombo, Pyrgoma elargatum Seguenza, Pyrgoma oulastreae Utinomi, Pyrgomina seguenzai Bałuk and Radwański, and Pyrgoma sulcatum Philippi.