Leopecten marquerensis (Durham, 1950)
DURHAM, J. W. 1950. Megascopic paleontology and marine stratigraphy. In: 1940 E. W. Scripps Cruise to the Gulf of California, pt. II: Geological Society of America Memoir 43, p. 1-216 [p. 67, pl. 14, figs. 1, 2]
1950 Patinopecten marquerensis Durham, 1950
J. W. Durham, 1950, plate 14.
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«Shell large; in general outline, ornamentation, and size very similar to P. bakeri. Right valve with about 20 prominent primary ribs, 1½ times as wide as the interspaces. Anterior and posterior to these are several finer ribs. Interspaces without intercalaries. Left valve with an equivalent number of low inverted V-shaped primary ribs, with three secondary riblets, one on each side and one at apex of V. Interspaces with a single intercalary riblet. On an unworn specimen the posterior margin has an area of fine ribbing similar to that on typical P. bakeri.
Dimensions of holotype: Height 154.5 mm, length 176.4 mm, thickness (both valves) 33.4 mm. Holotype no. 15475, paratypes nos. 15462, 15470 (loc. A 3518). OCCURRENCE: loc. A 3518. RANGE: upper Pliocene. REMARKS: One complete specimen, four left valves, and three right valves were available for examination from loc. A 3518. The inverted V-shaped ribs with three secondaries on the left valve together with the absence of any intercalaries on the right valve, and the central primary ribs of the right valve being half again as wide as the interspaces separates this species from P. bakeri and its subspecies diazi.» JOHN WYATT DURHAM, 1950
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