Argopecten percarus (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. 13, pl. 2; figs. 2, 5]
1925 Pecten (Aequipecten) percarus Hertlein, 1925
L. G. Hertlein, 1925, plate 2.
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«Shell moderately large, equilateral, subequivalve, moderately thin, somewhat compressed, the outline round. Right valve ornamented by about 22 moderately strong, rounded ribs, separated by round-bottomed interspaces which are not quite as wide as the ribs; ribs and interspaces sculptured by regular, wavy, incremental lines, and, at irregular intervals, by stronger lines of growth; hinge line about one-half as long as the disk and slightly indented at the beaks; ears unequal, the anterior with a large byssal notch and sculpture consisting of about six or seven radiating riblets, the posterior ear ornamented by about seven radiating riblets, both ears sculptured by incremental lines. Left valve more arched and sharper at umbo than right, and somewhat one-sided in appearance, the disk ornamented by about 25 or 26 rounded, radiating ribs, and also concentrically sculptured much as on right valve; ears ornamented by about six or seven radiating ribs, crossed by concentric incremental lines; ears slightly concave, anterior with a slight byssal notch. Altitude 82 mm.; longitude 91 mm.; diameter approximately 12 mm.; apical angle of valves approximately 118°.
Type: No 42 (L.S.J.U. type collection), from Loc. 48 (L.S.J.U.), mouth of large arroyo northwest of Elephant Mesa, Scammon Lagoon Quadrangle, Lower California; Paratypes: No. 43 (L.S.J.U. collection) and Nos. 1768, 1769 (C.A.S. collection), B. F. Hake collector, Salada Pliocene. This species is also found at Loc. 76 (L.S.J.U.), Salada on white clay northwest of Elephant Mesa west of Arroyo, Scammon Lagoon Quadrangle, Lower California ; B. F. Hake collector; Salada, Pliocene. Also Loc. 928 (C.A.S.), Cedros Island; G. D. Hanna collector; Upper Pliocene. Also Loc. 930 (C.A.S.), from Turtle Bay, Lower California; G. D. Hanna collector; Salada, Pliocene. Pecten percarus is distinguished from other west American Aequipectens by its large size, number of ribs, and its clear concentric incremental lines.» LEO GEORGE HERTLEIN, 1925
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