Cyclopecten aotus (Olsson, 1922)
OLSSON, A. A. 1922. The Miocene of Nothern Costa Rica with notes on its general stratigraphic relations. Bulletins of American Paleontology, 9 (39): 177-483, pls. 1-32. [p. 376, pl. 18, figs. 17, 18]
1922 Pecten (Pseudamusium) [sic] aotus Olsson, 1922
A. A. Olsson, 1922, plate 18.
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«Shell small, thin, depressed or but slightly convex and Amusium-like; both valves except on magnification appearing smooth; ears of the left valve large and subequal; the anterior ear of the right valve about twice that of the posterior and carrying a deep, byssal notch; the surface of the left valve on magnification is seen to be sculptured with fine, radial lines which often occur in irregular streaks or blotches, imparting a peculiar appearance to the shell; the right valve is perfectly smooth and featureless, except for a band of rough scales on its anterior ear above the byssal notch; interior of shell cavity shallow, a simple ventral margin and the hinge-line vertically grooved with fine lines.
Length 4.5, height 4.5, diameter .75 mm. left valve.
Differs from Pecten oligolepis Brown and Pilsbry in its larger size, thinner and more Amusium-like shell, and strongly sculptured left valve. This sculpture consists of fine lines or camptonectes striations, which may be uniformly distributed but more usually occur in irregular streaks or blotches, imparting a distinctive appearance to the surface. This sculpture is seen only on a slight magnification, the shell otherwise appearing smooth and featureless. It is quite common in the coralline limestones of Port Limon.
Gatun Stage: Port Limon.
Coll. 5, Red Cliff Creek» AXEL ADOLPH OLSSON, 1922
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«Cyclopecten aotus (Olsson, 1922) from the Pliocene of Puerto Limon, Costa Rica, based on the larger of two syntypes (PRI 21161), is probably a junior synonym of C. nanus because of similar fine costae on its left disk and auricles as well as similarities in shape. The "Camponectes striations" said by Olsson (1922: 204) to be present in C. aotus are diagenetic features due to epitaxial crystallization of calcite, precisely as described above in Bowden 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. 21, 22]
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