Early Miocene; Extinct.
Original Description (from Dall, 1903, p. 1375):
"Oligocene of the Chipola River, Florida; of the lower bed at Alum Bluff, Chattahoochee River, Florida, and of Hawkinsville, Georgia; Dall and Burns.
Shell large, rather thin, compressed, with small, pointed, recurved beaks, over a small, narrow, rather deeply impressed lunule; there is no anterior dorsal area; the posterior area is long, narrow, and divided into two nearly equal parts by an impressed line; sculpture of fine, slightly irregular concentric raised threads, stronger distally, sublamellose on the dorsal area, fainter in the middle of the disk, and rather close-set; radial sculpture of faint, obscure, slightly vermicular markings, hardly visible except in the middle of the disk; anterior adductor scar elongate; posterior short, ovate; cardinal teeth well developed; ligament short, deeply inset. Alt. 75, Ion. 71, diam. about 11 mm.
The figure of this species is restored from a number of fragments which give practically all the characters except the hinge of the left valve. It is a large, very compressed form belonging in group B."
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