The western North American genus, Paciocinebrina Houart, Vermeij, and Wiedrick 2019, is both impressively speciose and phenotypically plastic, challenging the views of both lumpers and splitters. A recent study has revealed that the northeastern Pacific species of Paciocinebrina are distinct from the European type species, Ocinebrina aciculata (Lamarck, 1822) and other eastern Atlantic species, including Ocenebra Gray, 1847. Based on newly collected specimens and material already available, mostly from California, a spiral morphology comparison of six new species are herein described, including habitat and distribution records. |