Lyropecten modulatus (Hertlein, 1925)
HERTLEIN, L. G. 1925. Pectens from the Tertiary of Lower California. Proceedings of the California Academy of Sciences [4th Series], 14 (1): 1-35, pls. 1-6. [p. 11, pl. 3, fig. 6]
1925 Pecten (Lyropecten) modulatus Hertlein, 1925
L. G. Hertlein, 1925, plate 3.
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«Shell moderately convex, fairly heavy, showing slight areas of constricted growth. Right valve ornamented by about 14 longitudinally sculptured radiating ribs, which are rounded in the earlier part of the shell, but which, toward the ventral margin, show a tendency to become flattened; interspaces of varying width but all narrower than the ribs, all containing a small midrib; anterior and posterior margins of shell ornamented by fine longitudinal riblets; ears unequal, the anterior ear large, with large byssal notch and sculpture consisting of about seven well defined radial riblets and concentric growth lines, the left ear small in comparison with the large right, its posterior edge sloping down almost vertically to the margin of shell, the surface of the ear ornamented by about eight or more radiating riblets over which are superimposed fine longitudinal and concentric lines. Altitude 58 mm.; longitude 60 mm.; diameter of right valve approximately 14 mm.; apical angle, right valve approximately 92°.
Type: Right valve, No. 39 (L.S.J.U. type collection), from Loc. 43 (L.S.J.U.), Mesa west of Mesa de las Auras, Scammon Lagoon Quadrangle, Lower California; B. F. Hake collector; Salada, Pliocene. Pecten modulatus bears some resemblance to P. vaughani Arnold, but is much larger and also has sculptured margins and prominent midriblets in the interspaces, while in P. vaughani the interspaces bear fine striae only.» LEO GEORGE HERTLEIN, 1925
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