Cyclopecten defuniak (Gardner, 1926)
GARDNER, J. 1926. The molluscan fauna of the Alum Bluff Group of Florida. Part I. Prionodesmacea and Anomalodesmacea. United States Geological Survey Professional Paper, 142-A: 1-79, pls. 1-15, 1 map [p. 49, pl. 12, figs. 10-12]
1926 Pseudamussium defuniak Gardner, 1926
J. Gardner, 1926, plate 12.
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«Shell very small, rather thick, porcellanous, the disk a rude sector of about 90°. Right valve moderately inflated, obliquely flattened toward the umbones.
Left valve flattened. Umbones acute, rising a little above the hinge line. Anterior dorsal margins acutely angulated, slightly more produced than the obtusely angulated posterior margins. Surface of disk smooth except for exceedingly faint traces of a striation like that of Camptonectes, visible only under high magnification on a single individual. Traces of a blotchy color pattern also discernible. Auricles rather small, those of the left valve subequal, the anterior auricle of the right valve higher and more produced than the posterior; anterior auricle cut off from the disk by a narrow but well-defined byssal groove. Margin sharply elevated along the groove and outlined by an obscure thread; traces of one or two more threadlets and a feeble concentric lamination commonly visible near the notch; right posterior auricle not sharply differentiated from the disk and apparently free from sculpture; left anterior auricle and submargin shagreened with an exceedingly fine concentric lamination and radial threading, which becomes obsolete toward the hinge; left posterior auricle and submargin merging smoothly into one another and into the disk, faintly lineated away from the hinge line but showing no trace of a concentric imbrication. No trace of a ligament area along the hinge margin. Resilial pit minute; provinculum still retained on all the individuals in the shape of fine ridges normal to the hinge margin, the ventral margin of the provinculum expanding slightly about halfway between the ligament pit and the distal extremities of the hinge. Adductor scar very obscure, apparently rather small, quite strongly posterior, and about midway between the dorsal and ventral margins. Pallial line also obscure. Inner surface of valve smooth. Dimensions: Altitude of right valve, 3.8 millimeters; left valve of another individual, 4.6 millimeters. Latitude of right valve, 3.75 millimeters; left valve, 4.6 ± millimeters. Cotypes: U. S. Nat. Mus. No. 352453. Type locality: No. 5618, 3^ miles southwest of De Funiak Springs, Walton County, Fla. The relationship of this small form to P. guppyi Dall is certainly very close, but it is smaller, the right valve is less convex and the left valve more flattened than in guppyi. The dorsal margins are also less sharply defined as a rule. The Camptonectes sculpture has been observed on only a single individual of defuniak and very obscurely on that, and the ventral expansion of the provinculum is not so marked as in guppyi. The single valve from Oak Grove, which was referred by Dall to guppyi, is possibly specifically identical. The threading upon the auricles is less fine, however, and not so restricted as in defuniak. Occurrence: Shoal River formation, localities 72641r, 10608r , 5618p.» JULIA GARDNER, 1926
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«Cyclopecten defuniak (Gardner, 1926), from the Middle Miocene Shoal River Formation of Florida, closely resembles C. guppyi in shape, but the latter species has a more inflated left valve and less prominent costellae on left auricles. The anterior margin of the right anterior auricle of C. defuniak is evenly rounded, whereas that of C. guppyi slants upward fromthe byssal notch before curving to meet the dorsal margin.»
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, 23]
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