Camptonectes moodyi (Stephenson, 1952)
STEPHENSON, L. W. 1952. Larger invertebrate fossils of the Woodbine formation (Cenomanian) of Texas. United States Geological Survey Professional Paper, 242: 1-211, pls. 8-58 [p. 79, pl. 19, figs. 8, 9]
1952 Pecten (Camptonectes) moodyi Stephenson, 1952
1952 Pecten (Camptonectes) martinsensis Stephenson, 1952
1952 Pecten (Camptonectes) martinsensis Stephenson, 1952
L. W. Stephenson, 1952, plate 19.
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«Shell of medium size, depressed-convex, slightly higher than long, slightly inequivalve, the left valve more inflated than the right. Beaks small, depressed, direct, not projecting above the hinge line, situated at the midlength: Right anterior ear about twice as long (measured on upper border) as high, with lower border parallel to the dorsal border and with the anterior end truncated, the upper corner squarish, the lower corner rounded; this ear is separated from the main body by a narrow, shallow, oblique, beaded sinus, which terminates below at the inner end of a profound byssal notch. Posterior ear of right valve smaller than the anterior ear, triangular in outline, with its long, sharply defined inner margin forming the line of separation from the main shell. The anterordorsal margin of the main shell is broadly concave upward in trend, and the posterodorsal margin is straight; these margins diverge from the beak at an angle of about 85°. The surface is covered with numerous, crowded, flat-topped, low, radiating bifurcating ribs, separated by sharp, narrow interspaces. As the ribs pass downward away from the umbo they trend in broad curves, on the one hand, toward the anterior margin and, on the other, toward the posterior margin. On the holotype the shell layer bearing the ribs has been peeled off on the central and urnbonal parts of the surface. On the remaining surface the ribs are markedly irregular in trend, in width, and in arrangement on different parts of the shell; the ribs near the ventral border are narrower and more numerous than those on earlier stages of the shell. On the figured paratype, a left valve, the ribbing is somewhat more regular than on the holotype. On the right anterior ear of the holotype radial ribbing is obscure; the ribbing of the posterodorsal slope of the main shell continues out across the posterior ear with diminishing strength.
Dimensions of the holotype, a right valve: Length 35 mm, height 38 mm, convexity about 5 mm. Hinge line straight, about two-thirds as long as the shell. A narrow crural ridge closely parallels the upper hinge margin. Under the beak is a small triangular ligamental pit opening inward, and from this a narrow crural ridge runs forward and downward on the inner surface of the right anterior ear; no corresponding ridge is present on the left anterior ear. Compared with Pecten (Camptonectes) bellisculptus Conrad from the Woodbury clay at Haddonfield, N. J. (1869b, p. 99), the radial sculpture of this species is very much coarser. The species has many features m common with Pecten (Camptonectes) bubonia Stephenson, from the Owl Creek formation, 2.5 miles northeast of Ripley, Miss. (1941, p. 131), but is more coarsely and less regularly sculptured, and has the right anterior ear only obscurely ribbed and a little higher in proportion to its length. The fact that the Lewisville species, P. (Camptonectes) moodyi (early Upper Cretaceous), and the Owl Creek species, P. bubonis (late Upper Cretaceous), are so similar in their specific characters indicates that representatives of the subgenus Camptonectes lived through Upper Cretaceous time without marked change. Pecten (Camptonectes) platessa White (1877, p. 176), from Cretaceous strata 5 miles west of Mineral Springs, Ariz., is a closely related species, but the outer surface of the holotype is too imperfectly preserved for specific identification. Types.— Holotype, U.S.N.M. 105235; 2 unfigured paratypes, U.S.N.M. 105236: 1 figured paratype, U.S.N.M. 105237; all from near old Slate Shoals, Red River, 8 miles east of Arthur City, Lamar County. Three unfigured paratypes, U.S.N.M. 105238. Named In honor of Clarence L. Moody of Shreveport, La.
Occurrence.— Grayson County: Loc. 160; Lamar County: locs. 201 (holotype, 3 paratypes, 1 figured), 203 (3 unfigured paratypes). Range.—Templeton member.» LLOYD WILLIAM STEPHENSON, 1952
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«Another species that is similar in size, shape and ornament is C. moodyi (Stephenson, 1952) (p. 79, pl. 19, figs. 8, 9) from the Cenomanian Woodbine Formation
of Texas. The umbonal angle is similar to that of C. tutorae, and it has approximately the same number of striae along the shell margin, and thus a comparable ‘‘density’’. However, it differs in showing more strongly impressed antimarginal striae, better developed growth lines, and a shell height that exceeds its length. Auricle ornament also differs in that the weak radials and lamellose commarginals seen in C. tutorae are missing. Similar to C. moodyi is C. ellsworthensis Stephenson, 1952 (p. 80, pl. 19, figs. 5, 6), based on material collected at the same localities and from the same strata. This differs from C. moodyi only in showing a finer ornament (i.e., more closely packed striae, about 100 along shell margin). This, together with the slightly narrower umbonal angle and taller shell, suffice to differentiate it from C. tutorae. Of two other species described by Stephenson (1952), C. martinsensis (p. 80, pl. 19, figs. 1-4) appears to represent juveniles of C. moodyi, while C. cavanus (p. 80, pl. 189, fig. 7) is based on two poorly preserved specimens, whose ornament cannot be clearly observed.» CASADÍO, S., M. GRIFFIN & A. PARRAS. 2005. Camptonectes and Plicatula (Bivalvia, Pteriomorphia) from the Upper Maastrichtian of northern Patagonia: palaeobiogeographic implications. Cretaceous Research, 26: 507-524. [p. 513]
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