Cyclochlamys Finlay, 1926

Dijkstra, Henk H. & Beu, Alan G., 2018, Living Scallops of Australia and Adjacent Waters (Mollusca: Bivalvia: Pectinoidea: Propeamussiidae, Cyclochlamydidae and Pectinidae), Records of the Australian Museum (Rec. Aust. Mus.) 70 (2), pp. 113-330 : 158

Cyclochlamys Finlay, 1926

Cyclochlamys Finlay, 1926: 452 . Type species (by original designation): Pecten transenna [sic] Suter, 1913; Recent, near the Snares Islands , New Zealand, 91 m; widespread around New Zealand.

Diagnosis. Shell inequivalve, minute, circular to posteriorly oblique; protruding conical to triangular prodissoconch on left valve, almost flat on right valve; left valve sculptured with radial and/or commarginal riblets or striae or smooth, right valve with commarginally elongate hexagonal (honeycomb-like) microstructure (simple calcitic prismatic outer layer); auricles unequal; byssal notch well-developed; no ctenolium; no internal lirae.

Distribution. Oligocene?; lower Miocene–Recent (Cotton, 1961: 104; Pastorino & Griffin, 2018: 2). Australia, New Zealand, subantarctic, Japan, 73– 274 m. A species referred previously to Cyclopecten from the latest Eocene or earliest Oligocene (early Whaingaroan New Zealand Stage) Ototara Limestone in North Otago, New Zealand (Robinson & Lee, 2011, p. 138, fig. 3D–H) has a characteristic outer layer of elongate hexagonal calcite prisms on the right valve and is referred to Cyclochlamys , although it also has weak commarginal ridges and possibly belongs in Chlamydella .

Discussion. Cyclochlamys Finlay, 1926 was erroneously mentioned as a “nom. null.” by Hertlein (1969: N353), but is an available name, and is distinguishable from Cyclopecten Verrill by its pteriiform shell, its tall, conical prodissoconch on the left valve, and the commarginally elongate hexagonal (honeycomb-like) microsculpture of the right valve. The genus is known from New Zealand, southern Australia, the subantarctic region (Hayami & Kase, 1993), southern Japan (Hayami & Kase, 1993: 61), the Southwest Pacific (Dijkstra & Maestrati, 2012: 394), and southern Argentina (Pastorino & Griffin, 2018).