Early Miocene; Extinct.
Original Description (from Dall, 1900, p. 1019):
"Oligocene of the Chipola River, at Macdonald's farm, Calhoun County, Florida; Burns.
Shell elongate, subequilateral, slender, with inconspicuous beaks, rostrate, and sharply sculptured, with low, elevated, close-set concentric lamellae, which become sparser and more prominent on the posterior part of the shell, especially on the rostrum; posterior dorsal area with two radial folds separated by a shallow sulcus, the upper fold obscure; lunule very narrow, moderately impressed; rostrum of the left valve ending in a narrow sharp point; teeth normal, small; in the left valve obscure; pallial sinus elongate, two-thirds confluent below, rounded behind. Lon. 27, alt. 11, diam. 5 mm., but probably reaching a size one-third greater, judging by fragments collected.
This shell recalls T. cumingii, though smaller and more delicate."
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