Euvola gorda (Olsson, 1964)
OLSSON, A. A. 1964. Neogene mollusks from Northwestern Ecuador. Paleontological Research Institution, Ithaca, N.Y., 256 pp., pls. 1-38. [p. 33, pl. 4, figs. 3-3a]
1964 Pecten (Pecten) gorda Olsson, 1964
A. A. Olsson, 1964, plate 4.
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«The shell is small or of medium size, subcircular, thin, the right valve strongly convex with large, flat or low, rounded ribs between narrow grooved interspaces, the left valve concave and with narrower ribs set between wide interspaces. The left valve is deeply concave in the middle, with the marginal zone on all sides curving upward, its surface neatly sculptured with about 13, narrow ribs, their interspaces about twice as wide, the whole closely overrun with fine raised concentrics. Ears of the left valve are nearly equal, their outer surface so deeply impressed that they bulge sharply inward. Flutes of the ribs on the internal surface show only near the middle of the ventral margin.
Length 28.3 mm., height 27.4 mm., diameter 4.7 mm. A left valve, Sua. Holotype, USNM 643795. The above description is based largely on a single left valve. It is associated with a fragment of a right valve which is thin, strongly convex, with large, flattened to low, rounded ribs set between narrow or grooved interspaces. This right valve is similar to other specimens from Punta Gorda, clearly the same species (Pl. 4, fig. 3a) in which the rounded ribs number about 21. The fossil resembles P. perulus Olsson, a living species along the Ecuadorian coast, in size, shape, thinness of shell, and in major features of its sculpture, but the Recent species has more numerous ribs which are mesially grooved ventrally. Esmeraldas formation: punta Gorda. Miocene; Sua; Mompiche-Portete.» AXEL ADOLF OLSSON, 1964
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