Early Miocene to Late Pliocene; Extinct.
Southern Florida to northern Florida.
Original Description (from Dall, 1898, p. 729-730):
"Oligocene of White Beach, Osprey, Florida, and of the Chipola River at Bailey's Ferry, Florida, Burns and Dall; lower bed at Hawkinsville, Georgia, Burns.
Shell small for the group, subequilateral, slightly inequivalve, the right valve more convex with nine to thirteen strong, undulated, rounded, more or less nodulous, finely radially striated ribs, the undulations affecting the whole of the disk, sudden and very pronounced, giving a side view of the valve somewhat the aspect of a clenched fist; interspaces narrower radially, finely threaded, the whole valve with fine concentric lamellation somewhat prickly or limose at the intersections; submargins rather wide, radially finely striate; ears small, subequal, the surface coarsely radially threaded, the byssal ear produced with a conspicuous sinus and fascicle; ctenolium well marked; inner basal margin fluted by the ribs; cardinal margin with two or three strong crural ridges. Alt. 40, lat. 45, diam. about 22 mm.
This is an interesting species, peculiar from its small size and the abruptness of its knuckle-like undulations. Some specimens, however, are but little undulated, and the mutations are much the same as occur in other species of the section.
The following species, while they are related by sculpture, form, and conchological character to the Nodipecten type, are not known to form nodules; the ribs may be slightly tumid at intervals or periodically undulated, but there are no hollow bullae, as in the more typical forms. But these characters are precisely those of the non-nodulous varieties of the nodulous species, and so I feel justified in including them in this section."
To access this description in its original formatting through the Biodiversity Heritage Library, click here.