Lindapecten cortezianus (Durham, 1950)
DURHAM, J. W. 1950. Megascopic paleontology and marine stratigraphy. In: 1940 E. W. Scripps Cruise to the Gulf of California, Part. II. Geological Societyof America Memoir, 43: 1-216, pls. 1-48. [p. 64, pl. 10, figs. 2, 3, 6]
1950 Chlamys corteziana Durham, 1950
J. W. Durham, 1950, plate 10.
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«Pecten sancti-ludovivi Anderson and Martin, HANNA (1926), Proc. Calif. Acad. Sci., ser. 4, vol. 14, p. 473, pI. 22, figs. 1, 2, 3; not Pecten sancti-ludovici ANDERSON AND MARTIN (1914).
Shell of medium size, right valve slightly more inflated than left; sculpture discrepant on the two valves; right valve with 17-18 low rounded ribs with interspaces about equal in size, ribs and inter-spaces each bearing equally spaced finely beaded riblets with an occasional tertiary riblet present; near umbo the primary ribs are higher and nearly square-sided but as shell becomes larger ribs spread out and become low and rounded; anterior ear of right valve with about 12 fine beaded riblets; riblets on posterior ear less distinct than on anterior; left valve with a corresponding number of high, square-sided and noded ribs about two thirds as wide as flat-bottomed interspaces, occasionally a secondary beaded, flat-sided riblet is developed on sides of primary rib.
Dimensions of holotype (incomplete ventral margin): Length 32.8 mm, height (estimated) 31.5 mm, thickness (one valve, estimated) 7 mm. Holotype no. 30564 (loc. A 3579); paratype nos. 34031, 34032 (loc. A 1267). OCCURRENCE: locs. A 1267 (Imperial formation) and A 3579 (San Marcos formation). RANGE: lower Pliocene. REMARKS: This species somewhat resembles Chlamys lowei (Hertlein) living in the Gulf of California but may easily be separated by the larger posterior ear and more rounded interspaces on the right valve. Pecten (Chlamys) buchivacoanus F. and H. Hodson and its subspecies from the Miocene of Venezuela is another closely related species, but its left valve has many more secondary and tertiary riblets. This species is rather abundant in the Imperial formation at loc. A 1267.» J. WYATT DURHAM, 1950
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