Argopecten venezuelanus (F. & H. Hodson in F. Hodson et al., 1927)
HODSON, F., H. K. HODSON & G. D. HARRIS. 1927. Some Venezuelan, and Caribbean mollusks. Bulletins of American Paleontology, 13 (49). [p. 25, pl. 14, fig. 6; pl. 15, figs. 2, 4-5; pl. 17, fig. 1]
1927 Pecten circularis venezuelanus F. & H. Hodson in F. Hodson et al., 1927
F. Hodson, H. K. Hodson & D. Harris, 1927, plates 14, 15, 17.
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«This subspecies, which is very common in the Miocene of Venezuela, stands exceedingly close to the recent Pecten circularis Sowerby¹ from the Pacific coast. While there are some variations which cannot be told from variations of the recent species, it is not difficult to separate most of the Venezuelan forms from the recent P. circularis by slight but rather constant differences. Our subspecies is slightly smaller, and the umbones are more pinches due to a narrowing and inflating of the umbones between the tips of the beaks and the submargins. The anterior ear usually shows stronger striae than are present on the recent P. circularis; there are 4 or 5 strong striae on the anterior ear of the right valve. In our large collections from many localities, we find many variations and all intergradations between the species, sensu stricto, and our subspecies venezuelanus, as well as between this subspecies and the subspecies cornellanus. The specimens average about 40 mm. in altitude.
Age: Miocene and Pliocene. Locality: Common in the State of Falcón, locality numbers 68, 68A, 69, 70A, 71, 73, 74A, 75 (and variation), 78, 79 (and variation), 80, 81, 82, 83, 83A, 83B, 84, 85 (and variation), 88 (variation), 90, 91, 95, 96, 97, 98, 110, 111, 115, 118, 119, 120, ;125, 150, 150A, 150B (and variations), 151, 154, 169A, 178, 184, 185, 186, 187, 1188, 196, 197, 198, 202, 205, 205A, 206, 206A, 207, 208, 209, 215, 216, 219, 220, 220A, 222, 225, 225A, 242 (variation 243 (cf.), 290, 291, 296, 297, 298, 299 (variation), 300 (variation), 304, 307, 675, 697, 1000, 1004, 1006, 1011, 1026, 2027, 1030 (and variations), 1031, 1033, 1046 (variation), 1064, 1071 (variation), 1072, 1111, 1232, 1248 (and variation), 1255, 1332, 1353, 1354, 1430, 1450, 1500, 1867 (?), 1868, 1869, 1931C, 2054 (and variation), 2208». ¹ Proc. Zool. Soc. London, 1835, p. 110. FLOYD HODSON & HELEN K. HODSON, 1927
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«Moderately large, height and length subequal, valves of moderate and subequal convexity, or right valve slightly more convex than left, auricles subequal. Ribs high, inverted U-shaped, crest arched; ribs wider than interribs, moderately wider to as much as two or three times as wide, especially on right valves; 17 to 22 (generally 19 or 20) on both valves. Fine concentric lamellae in interribs, absent on crest of ribs. Radial sculpture on right anterior auricle moderately stronger to much stronger than on posterior. Radial sculpture of left auricles weak to moderately strong. Byssal notch narrow, deep. Ctenolium absent on few valves where it would be exposed. A pair of strong cardinal crura.
Length 42.3 mm, height 40.2 mm, convexity about 8 mm (larger figured specimen). Length 46.7 mm, height 45 mm, convexity about 8 mm (largest specimen). Type: Paleontological Research Inst. 21931. Type locality: La Vela area, Falcón, Venezuela, middle or late Miocene. A species of Argopecten identified as A. venezuelanus is abundant in the upper member of the Alhajuela formation, represented by 67 specimens, 3 of which are articulated. They range in length from 10 to 46.7 mm. In size, sculpture of disk and auricles, and variation in width of interribs they closely resemble Venezuelan specimens, although the fossils from Panama are consistently a little less convex. It is suggested that A. venezuelanus is a predecessor of the eastern Pacific A. circularis (Sowerby) and its western Atlantic analog A. gibbus (Linne). The earliest comparable species in southeastern United States A. choctawhatcheensis (Mansfield) and A. comparilis (Tuomey and Holmes are of late middle and late Miocene age, respectively (Waller, 1969, p. 53, 55, fig. 6). Their relations to A. venezuelanus are undetermined. Both living species are larger and more convex than A. venezuelanus, and their right anterior auricle is less strongly sculptured. Occurrence: Upper member of Alhajuela formation (early Miocene), localities 85, 85a, 89, 90, 90a, 91. Deposits of middle or late Miocene age, Falcón, Venezuela.» 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. 596]
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Argopecten venezuelanus (F. and H. Hodson): W. P. Woodring, 1982, Geology and paleontology of Canal Zone and adjoining parts of Panama, plate 105, figures 1-3, 7.
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