Pleuromeris Conrad, 1867

Pérez, Damián E. & Del Río, Claudia J., 2017, Systematics of the family Carditidae (Bivalvia: Archiheterodonta) in the Cenozoic of Argentina, Zootaxa 4338 (1), pp. 51-84 : 69-70

Genus Pleuromeris Conrad, 1867

Type species. Pleuromeris decemcostata Conrad, 1867 (p.12) (by original designation). Yorktown , Waccamaw , Choctawhatchee , Caloosahatche , Chowan River , James City and Tamiani formations, lower Pliocene-lower Pleistocene of Florida and North Calorina, United States of America (USA) (revised herein).

Diagnosis. Carditid with small shell (less than 30 mm in length) and a subtriangular outline. Umbo subcentral. Lunule large and broad. Right middle tooth triangular and broad. External sculpture of 11 to 22 radial ribs covered with nodes, with subtriangular transverse section.

Included species. P. acaris Dall, 1903 (Miocene–Pliocene, Jamaica, Panama, Trinidad and Tobago and Venezuela), P. archaenepeanensis Chapman & Crespin, 1928 (lower Pliocene, Australia), P. auroraensis Ward & Blackwelder, 1987 (Pliocene–Pleistocene, North Carolina), P. armilla ( Dall, 1903) (Recent, USA), P. benthicola Powell, 1937 (Recent, New Zealand), P. conradiana Gabb, 1881 (Pliocene, Costa Rica), P. finlayi (upper Pliocene– lower Pleistocene, New Zealand), P. fueguina (middle Miocene, Argentina), P. hectori Powell, 1938 (upper Pliocene–lower Pleistocene, New Zealand), P. instata Laws, 1944 (Miocene, New Zealand), P. kapuensis (Marwick, 1931) (upper Miocene–lower Pliocene, New Zealand), P. koruahinensis ( Bartrum & Powell, 1928) (lower Pliocene, New Zealand), P. latiuscula Powell, 1937 (Recent, New Zealand), P. micella Olsson & McGinty, 1958 (Recent, Caribbean Sea), P. otamateaensis Laws, 1944 (lower Miocene, New Zealand), P. pecten Tate, 1886 (Miocene, Australia), P. prolutea ( Marwick, 1929) (upper Oligocene, New Zealand), P. scitula Dall, 1903 (early Miocene, Florida), P. scituloides Olsson, 1941 (Pliocene, Florida), P. sulcolunularis ( Ihering, 1907) (upper Oligocene–lower Miocene, Argentina), P. tellia Dall, 1903 (lower Miocene, Florida), P. tridentata ( Say, 1826) (upper Pliocene–Recent, USA and Caribbean Sea), P. ultima Dell, 1956 (lower Miocene, Florida), P. volckmanni ( Philippi, 1887) (Miocene, Chile), P. waitorana Laws, 1940 (upper Pliocene, New Zealand), P. zelandica ( Deshayes, 1854) (lower Pliocene–Recent, New Zealand).

Remarks. According to Conrad (1867) and Dall (1903), the main characters of Pleuromeris are the small size and subtriangular outline, sculptured with 11 to 22 radial ribs covered by nodes, and the presence of a triangular and broad right middle tooth. This genus has a wide geographic distribution and was recorded by Conrad (1867) in the Pleistocene–Recent of southeastern North America, and by Dall (1903) in lower Miocene strata of that region. Later, Powell (1937; 1938) mentioned Pleuromeris from the Pliocene and Recent of New Zealand and Darragh (1970) from the Miocene and Pliocene of Australia. Other South American records correspond to ‘ Cardita ’ volckmanni ( Philippi, 1887) (Miocene, Chile), assigned to Pleuromeris because of its subtriangular outline and radial ribs with nodes. Del Río (2004) included in Pleuromeris four species described by Ihering (1907): ‘ Venericardia ’ sulcolunularis , ‘ V.’ cannada , ‘ V.’ cruzensis and ‘ V.’ camaronesia . The last three species are placed in different genera in this work (‘ V.’ cannada and ‘ V.’ cruzensis in Cyclocardia , and ‘ V.’ camaronesia in Scalaricardita ).

Dall (1903) indicated the presence of ‘ Pleuromeris ’ parva ( Lea, 1833) from the Eocene of the USA but this species is better placed in Rotundicardia Heaslip, 1968 , because of its subcircular shell with tripartite radial ribs.

Pleuromeris sanmartini Klappenbach, 1970 , was described from the Recent of Uruguay, but this species has a posteriorly-placed umbo and wide and smooth radial ribs that are typical of Pteromeris Conrad, 1862 .