Pecten proteus Nomland 1917
NOMLAND, J. O. 1917. The Etchegoin Pliocene of Middle California. University of California Publications, Bulletin of the Department of Geological Sciences, 10 (14): 191-254, pls. 6-12. [p. 232, pl. 6, figs. 2, 2a, 2b, 2c]
«PECTEN PROTEUS, n. sp.
Plate 6, figures 2, 2a, 2b, 2c Type specimen no. 11089, Univ. Calif. Coll. Invert. Palae. Pecten deserti Conrad. Arnold, Ralph, U. S. Geol. Surv. Bull. 396, p. 76, pl. 26, figs. 3, 4, 1909.
Pecten deserti Conrad. Arnold, Ralph, and Anderson, Robert, U. S. Geol. Surv. Bull. 398, pl. 48, figs. 3, 4, 1910. Shell thin, equilateral, equivalve, compressed, with smooth regulary convex margins. Dorsal margins slightly concave; apical angle about 95 degrees. Right valve ornamented externally by 21-24 wide, moderately high, rounded ribs; on each side of major ribs is usually a faint auxiliary riblet; interspaces between major ribs less than width of ribs; anterior ear slightly longer than posterior, sculptured by about five low radial ridges and indistinct incremental lines; posterior ear ornamented with about seven low, radial ridges and nearly invisible incremental lines. Left valve in general similar to right, but has higher, more strongly rounded, major ribs with narrow interspaces; anterior ear with about seven radiating lines. Dimensions of rather small left valve of type: height, 37 mm.; width, 33 mm.; width of hinge line, 17 mm.
Specimen of this species found in the Coalinga region have heretofore been identified as Pecten deserti Conrad. On comparison of P. deserti from the type locality at Carrizo Mountain, San Diego County, with P. proteus, n. sp., several marked differences may be observed. In P. deserti the ribs are higher, flatter above, with more nearly vertical sides; on the left valve the ribbing continues without interruption from ears over the outer depressed dorsal margins, while in P. proteus, n. sp., the corresponding areas have no ribs. The ears of P. deserti are larger, more strongly curved, and have less depression where ears join dorsal margins of shell; also the dorsal margins show less marked concavity. These instances can be better recognized by seeing the comparative figures shown in this paper. Occurrence.— At localities 2991, 2975, with a large fauna characteristic of the Pecten coalingensis zone, upper Etchegoin.» JORGEN O. NOMLAND, 1917
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J. O. Nomland, 1917, plate 6.
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