Euvola ventonensis (Cooke, 1919)
COOKE, C. W. 1919. Tertiary mollusks from the Leeward Islands and Cuba. In: T. W. Vaughan (ed.), Contributions to the Geology and Paleontology of the West Indies, pp. 103-156. Carnegie Institution of Washington, Washington, DC [p. 130, pl. 12, figs. 1a-b]
1919 Pecten ventonensis Cooke, 1919
C. W. Cooke, 1919, plate 12.
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«The following is a description of this species:
Shell large, equilateral, inequivalve; right valve convex, with 23 to 25 rather high ribs, flattened on top, usually medially furrowed and closely transversely grooved or granulate, and separated by equal concave interspaces; left valve concave, with 23 or 24 narrow, even, rounded ribs, becoming obsolete towards the lateral margins, separated by wider, nearly flat interspaces; right submargins small, plane to convex, nearly smooth; left submargins strongly convex, narrow, nearly smooth; ears subequal, nearly straight, with a few narrow, obsolescent riblets, strongest on the right anterior ear; byssal notch shallow; both valves grooved internally in accordance with the external ribbing; secondary sculpture of fine, close, raised, concentric lamellae, extending over disk and ears alike, but very faint on the submargins and usually eroded from the ribs of the convex valve. Alt., 39 mm.; lat., 42 mm.; diam., 11 mm. This species is closely related to Pecten medius Lam., living off the southern Atlantic and Gulf coasts of the United States, from which it differs as follows: On the right valve the ribs of the fossil extend nearer to the beak, are higher, narrower, and more rugose than in P. medius; the number of ribs is within the range of variation of P. medius, but is less by one or two than the average for specimens of the same size. On the left valve the ribs are a little closer together and the lateral margins are less flaring than in P. medius. The right ears are about as in P. medius, but the left ears lack the two strong ribs which are nearly always present near the hinge line on each left ear of the living species. Localities.— One-half mile inland from the pier of the Juraguá Railroad, Santiago Bay, Willcox; Juraguá Railroad, La Cruz, first cutting on road, Vaughan; Vento, province of Havana, Wren; stations 3192, 3439, 4290, 5255. Geologic horizon.—Oligocene. Type.— U. S. Nat. Mus. No. 167102.» CHARLES WYTHE COOKE, 1919
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