Cyclopecten oligolepis (Brown & Pilsbry, 1913)
BROWN, A. P. & H. A. PILSBRY. 1913. Fauna of the Gatun Formation, Isthmus of Panama. Part 2. Proceedings of the Academy of Natural Sciences of Philadelphia, 64: 509-519, pls. 22-26, text-figs. 1-5 [p. 512, text-fig. 5]
1913 Pecten (Cyclopecten) oligolepis Brown & Pilsbry, 1913
Pecten aff. subhyalinus Smith; F. Toula, 1911, Eine jungtertiäre Fauna von Gatun am Panama-Kanal, II Teil, plate 31, figures 1a-1c.
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«Pecten app. subhyalinus Smith, Toula, J. B. der k.k. Geolog. Reichsanstalt, 1911, Bd. 61, p. 492, pl. 31, figs, 1a, b, c.
This shell is very close to the West Indian Cyclopecten simplex Verrill, but differs in details of sculpture. The right valve has concentric sculpture of excessively faint and fine striae, scarcely visible, and only under the compound microscope, and there are slightly more distinct radial threads near the edges. The left valve has rather widely spaced low concentric threads and more delicate radial threads, chiefly seen near the margins. In C. simplex the right valve is the more strongly sculptured, according to Verrill. The internal structure is substantially as figured for C. simplex (Trans. Conn. Acad., X, pl. 19, figs, 1, 2).
Length 2.8, height 2.7, diam of right valve .8 mm. From the excavation of the lower locks at Gatun. Pecten subhyalinus E. A. Smith, from the west coast of Patagonia, is somewhat higher than long, the hinge line is shorter and the valves somewhat less convex than in P. oligolepis.» AMOS PEASLEE BROWN & HENRY AUGUSTUS PILSBRY, 1913
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«Cyclopecten oligolepis (Brown & Pilsbry, 1913) from the Miocene La Boca and Gatun formations of Panama (Woodring, 1982: 576, pl. 104, figs 9, 12-13), is smaller than C. guppyi, seldom reaching 3 mm Ht, and has relatively larger posterior auricles, the posterior extremities of which are nearly as far extended as the posterior extremity of the disk. Many specimens of C. oligolepis have cancellate sculpture on the left disk caused by the intersection or radial costellae and widely spaced commarginal lirae. In other specimens, this cancellation is only weakly present and restricted to the umbonal region, and in some specimens the cancellation is also present on the proximal parts of the left auricles. Some specimens of C. oligolepis also have faint, very fine radial costellae on the right valve consisting of radially aligned tiny nodes on the commarginal bands of rectangular prisms. The pigment pattern preserved in a few specimens of C. oligolepis is like that described for C. guppyi.»
WALLER, T. R. 2011. Neogene Paleontology of the Northern Dominican Republic. 24. Propeamussiidae and Pectinidae (Mollusca: Bivalvia: Pectinoidea) of the Cibao Valley. Bulletins of American Paleontology, 381: 1-197, pls. 1-18. [p. 22]
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«Very small, right valve generally more convex than left. Prodissoconch generally preserved. Right valve generally smooth, exceptionally bearing faint concentric sculpture and still fainter radial sculpture. Left valve generally more or less distinctly sculptured with widely spaced, low concentric lamellae, exceptionally also bearing faint radial sculpture. Right anterior auricle longer than posterior, set off from disk by very narrow byssal fasciole. Left auricles subequal; with one exception, anterior auricle strongly depressed below level of disk, generally sculptured by continuation of lamellae on disk. Byssal notch narrow, moderately deep. No ctenolium. Interior vertically striate area adjoining dorsal margin well developed. A few left valves show faint maculated color pattern of small, elliptical blotches. Length 3.1 mm, height 3.0 mm (larger figured left valve). Length 3.6 mm, height 3.5 mm (largest specimen).
Type material: Lectotype, herewith designated, right valve illustrated by Brown and Pilsbry, Acad. Nat. Sci. Philadelphia 3843. Type locality: Gatun Locks excavation, Canal Zone, middle part of Gatun formation. This minute species, minute even for a Cyclopecten, occurs in the three parts of the Gatun formation—a total of 60 valves, left valves far outnumbering right. It is common, however, only in the middle part of the Gatun; in fact, two immature valves are the only representatives in the lower part of the formation and two valves are in a collection from the upper part. A right valve exposed in interior view and a left (?) valve that lacks shell material, both from the La Boca formation, are doubtfully identified as C. oligolepis, although they are of the right size for that species. In size and outline, C. oligolepis is most similar to C. pernomus (Hertlein, 1935, p. 320, pI. 18, figs. 11-13), a living eastern Pacific species. The auricles of the fossils are less strongly sculptured, and, for the most part, left valves are less convex. Though most species of the genus live in fairly deep water, the depth record for C. pernomus is 1 to 194 fathoms (Grau, 1959, p. 34). Occurrence: La Boca formation (early Miocene), Gaillard Cut area, localities 9ge (identification doubtful), 102a (identification doubtful). Lower, middle, and upper parts of Gatun formation (middle Miocene). Lower part, locality 136a. Middle part, eastern area, localites 139b, 147b, 147f, 147g, 155a, 155c, 157; western area, locality 169. Upper part, eastern area, locality. Deposits of middle Miocene age, Limon Province, Costa Rica (Olsson's (1922) record).» WOODRING, W. P. 1982. Geology and paleontology of Canal Zone and adjoining parts of Panama. United States Geological Survey Professional Paper, 306-F: 1-759, pls. 83-124. [p. 576, 577]
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Cyclopecten oligolepis (Brown and Pilsbry); W. P. Woodring, 1982, Geology and paleontology of Canal Zone and adjoining parts of Panama, plate 104, figures 9, 12, 13.
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