Leptopecten andersoni clemonensis (Etherington, 1931)
ETHERINGTON, T. J. 1931. Stratigraphy and fauna of the Astoria Miocene of southwest Washington. University of California Publications, Bulletin of the Department of Geological Sciences, 20 (5): 31-142, pls. 1-14. [p. 72, pl. 1, figs. 13, 15; pl. 4, figs. 2, 3; pl. 5, figs. 1-3]
1931 Pecten (Plagioctenium) andersoni clemonensis Etherington, 1931
T. J. Etherington, 1931, plates 1, 4, 5.
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«Description.— Shell medium sized, slightly wider than the height, subequilateral; left valve decidedly inflated; right valve slightly inflated; umbonal angle 90° on left valve, little more on the right valve; right valve sculptured with seven teen square, flat-topped ribs, smooth except for four or five faint radial riblets, crossed by looped concentric thread, especially visible near ventral margin of the shell; left valve with similar number of ribs, smooth, more rounded, usually narrower than interspaces; interspaces smooth except for concentric threads of which there are many more than on the right valve; auricles subequal; on the right valve the anterior auricle sculptured with four or five radial riblets crossed by concentric riblets giving the radials a more or less noded effect on unworn specimens. Byssal notch deep; posterior ear sculptured with three to four less prominent radials crossed by numerous concentric lamellae; left valve, both auricles sculptured with five to six fine radials crossed by fine concentric lamellae. Ctenolium includes seven or eight quite prominent denticles; single adductor muscle scar slightly posterior; ventral margins scalloped in harmony with the radial sculpturing.
This subspecies difers from the typical andersoni of the Temblor of California in the square, flat-topped ribs on the right valve which carries faint radial riblets. These faint riblets occur on Arnold's variation barkeranum on the left valve only. The ribs ou the left valve are rounder than on P. andersoni showing less of the sharp ridge effect. The left valve is slightly more inflated and slightly more equilateral than the typical forms. The new variety differs from variety gonicostus Trask, in the absence of "V"-shaped ribs, slightly more convex right valve, antl slightly more equilateral outline. It differs from P. alockamanensis Weaver in its more circular outline and more numerous ribs.
Type locaIity.— U.C. Iocality A-340.» THOMAS JOHN ETHERINGTON, 1931
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«Leptopecten andersoni clemonensis (Etherington, 1931)¹. Type locality: Grays Harbor County, southwestern Washington: Astoria (?) Formation (Moore, 1963: 67). Geographic range: Washington and Oregon (Addicott, 1976: 104). Age: Newportian molluscan stage, middle Miocene (Addicott, 1976: 104).»
Superscript 1 = Leptopecten andersoni group. 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. 138]
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«Two complete right valves ot this subspecies and numerous fragments were collected from the rocks exposed at Boiler Bay. Although A. andersoni clemonensis has been recorded in faunal lists of the Astoria formation in Oregon from other localities, no specimens have been found other than those from Boiler Bay, during the course of this study.
This subspecies differs from A. andersoni, as pointed out by Etherington (1931, p. 72), by having flattopped rather than rounded ribs on the right valve. Type: Univ. California 31933.
Type locality: Univ. California A-340. In cut on Clemons logging road, one-fourth of a mile south of the 8-mile post, sec. 26, T. 17 N., R. 7 W., Grays Harbor County, Astoria (?) formation, Washington. The type of A. andersoni clemonensis was not examined; this identification is based on the illustrations and description of the subspecies.
Localities: 65, 69a.
Occurrence elsewhere: Astoria (?) formation, Washington.» MOORE, E. J. 1963. Miocene Marine Mollusks from the Astoria Formation in Oregon. United States Geological Survey Professional Paper, 419: 1-109, pls. 1-32. [p. 67]
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Aequipecten andersoni clemonensis (Etherington); E. J. Moore, 1963, Miocene Marine Mollusks from the Astoria Formation in Oregon, plate 17, figure 1.
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«Observations. This variety which occurs in the middle Miocene Astoria formation of southwestern Washington bears a resemblance to the Astoria species P. alockamanensis in having a larger number of radiating ribs with broader interspaces and in a proportionately greater width com pared with the height. As pointed out by Etherington, it differs from the species andersoni in the presence of secondary radial ribs on the flattopped ribs of the right valve and in the more inflated right valve and the more pronounced rounding of the ribs.
Holotype. (U.C. 31933.) Locality (U.W. 427). Figured in the present report, pl. 19, fig. 5.
Paratype. (U.C. 31936.) Locality (U.W. 42). Figured in the present report, pl. 19, fig. 3. Geologic range. Astoria formation, middle Miocene. Geographic distribution. Southwestern Washington. Type locality. (U.W. 427.) In cut on demons logging road one-fourth mile south of the eight-mile post, Grays Harbor County, Section 26, T. 17 N., R.7 W.» WEAVER, C. E. 1943. Paleontology of the marine Tertiary formations of Oregon and Washington. University of Washington Publications in Geology, Volume. 5 [1942], (parts 1-3), p. 1-789, pls. 1-104. [p. 89]
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Pecten (Plagioctenium) andersoni Arnold subsp. clemonensis Ethering; C. E. Weaver, 1943, Paleontology of the marine Tertiary formations of Oregon and Washington, plate 19, figures 3, 5.
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