Subgenus Incacardium Olsson, 1944 Type species: Cardium (Incacardium) mellisum Olsson, 1944, by monotypy. Late Campanian, northern Peru. Remarks Cardium (Incacardium) Olsson, 1944 was transferred to the Cretaceous genus Pleuriocardia Scott, 1978, by Schneider (1995) based on the shared characters of symmetrical, concavedown, triangular spines rising from the middle of radial ribs and the shape or orientation of the right anterior cardinal tooth and right posterior cardinal socket. Neither hinge character can be confirmed for the Caballas Formation specimens. Pleuriocardia (Incacardium) differs from two other pleuriocardine subgenera, Pleuriocardia s.s. and Pleuriocardia (Dochmocardia) Scott, 1978, by having triangular radial ribs, rather than rounded radial ribs, and by having a posteroventrally directed broad sulcus (Olsson 1944).

Published as part of DeVries, Thomas J., 2019, Early Paleogene brackish-water molluscs from the Caballas Formation of the East Pisco Basin (Southern Peru), pp. 1533-1584 in Journal of Natural History 53 (25) on page 1549, DOI: 10.1080/00222933.2018.1524032, http://zenodo.org/record/3670229