Nanaochlamys anapleus anapleus (Woodring in Woodring et al., 1946)
WOODRING, W. P., M. N. BARMLETTE & W. S. KEW. 1946. Geology and Paleontology of Palos Verdes Hills, California. United States Geological Survey Professional Paper, 207: 1-145, pls. 28-37. [p. 81, pl. 34, fig. 15]
1946 Chlamys anapleus Woodring in Woodring et al., 1946
W. P. Woodring, M. N. Barmlette & W. S. Kew, 1946. plate 34.
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«The new name Chlamys anapleus (pI. 34, fig. 15) is proposed for a small Chlamys represented by a valve from the Lomita marl at locality 53 and another from the San Pedro sand at locality 30. It has 10 or 11 wide primary ribs, a weak secondary riblet in most of the interspaces, and is sculptured with microscopic punctation. The ventral margin of the type is bent, perhaps to form at a later stage a swelling, as in C. parmeleei. On the imperfect Lomita specimen some of the ribs are grooved. This Chlamys also might be considered a form of the C. islandicus group at the opposite extreme from C. opuntia in width of ribs. It was identIfied by Arnold as Pecten (Chlamys) hericeus var. strategus. "P." strategus, from Alaska, is considered a synonym of C. islandicus beringianus, a wide-ribbed Alaskan variety of C. islandicus. The ribs of C. anapleus do not enlarge so rapidly as in C. islandicus beringianus, and secondary ribs are weak or absent. The Pliocene C. parmeleei and its close Pliocene relative C. etchegoini have only half as many primary ribs. C. anapleus is not known to be living.»
WENDELL PHILLIPS WOODRING IN W. P. WOODRING ET AL., 1946
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«Pecten (Chlamys) hastatus Sowerby var. strategus Dall. Arnold, 1906, p. 113, pl. 44, figs. 2, 2a, 3, 4. Not Pecten hericeus var. strategus Dall,1898.
Chlamys anapleus Woodring, 1946, p. 81, pl. 34. fig. 15. Original description.—"The new name Chlamys anapleus * * * is proposed for a small Chlamys represented by a valve from the Lomita marl * * * and another from the San Pedro sand * **. It has 10 or 11 wide primary ribs, a weak secondary riblet in most of the interspaces, and is sculptured with microscopic punctuation. The ventral margin of the type is bent, perhaps to form at a later stage a swelling, as in C. parmeleei. On the imperfect Lomita specimen some of the ribs are grooved. This Chlamys also might be considered a form of the C. islandicus group at the opposite extreme from C. opuntia in width of ribs. It was identified by Arnold as Pecten (Chlamys) hericeus var. strategus. 'P.' strategus, from Alaska, is considered a synonym of C. islandicus beringianus, a wide-ribbed Alaskan variety of C. islandicus. The ribs of C. anapleus do not enlarge so rapidly as in C. islandicus beringianus, and secondary ribs are weak or absent. The Pliocene C. parmeleei and its close Pliocene relative C. etchegoini have only half as many primary ribs. C. anapleus is not known to be living." Holotype. — USNM 498642. Type Iocality.— USGS 12530. Los Angeles County, Calif. Basal part of San Pedro Sand, Pliocene. Comments.— Chlamys anapleus is higher in proportion to length, the ribs are smaller on the disk, the right-valve ribs are not bifurcate, and fewer and weaker secondary ribs are present in the interspaces than in Chlamys behringiana (Middendorf), a species living in Alaska. These two species somewhat resemble Nanaochlamys in sculpture. Geographic range.— Sottthern California. Geologic range.— Pliocene to Pleistocene. Occurrence in California.— Pliocene: Lomita Marl Member, San Pedro Formation; Pliocene and Pleistocene: San Pedro Sand (Woodring, 1946).» MOORE, E. J. 1984. Tertiary Marine Pelecypods of California: Propeamussidae and Pectinidae. United States Geological Survey Professional Paper, 1228-B: iv + B1–B112, figs. 1-2, pls. 1-42. [p. B29]
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Chlamys anapleus Woodring; E. J. Moore, 1984, Tertiary Marine Pelecypods of California, plate 7, figures 4, 6.
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«Remarks: In 1946, during Woodring's study on geology and paleontology of the Tertiary deposits of Palos and Verdes hills of California, the species Chlamys anapleus was distinguished "for the small Chlamys, which was represented by valves from the marl of Lomita and other valves from sandstone of San-Pedro" (Woodring, Bramlette, Kew 1964, p. 81). Disposing only with thesee two specimens, Woodring gave a very short description without measurement. Moreover, he pointed out to the curvature of the posterior margin of the disk, which "probably forms a convexity, as in C. parmeleei (p. 81). Woodring considered the new species as anology form, which was describedby Arnold (1906) as Pecten (Chlamys) hericeus var. strategus. Really, Arnold as Woodring pointed to the microscopic alveolus of the shell, and to increasing the convexity of the valve after reaching 20 mm in height (i.e. in formatipn of concentric stages). In the drawing of Arnold, the developing stage of the right valve is well-observed (Arnold, 1906; pl. 44, fig. 2) as well as the complicated structure after it. All this gives the possibility to say that both authors have one and the same view.
During the study of the Kovran fauna of Kamchatka Island, A. P. Ilina (1963) briefly described Ch. (Ch) anapleus and gave it one representation as a shell which is not large.
Up till now, all collections had bivalves perfectly of the adult specimens, and the former author suggested only a small number of shells of the younger individuals.
During a detailed description and collection of the fauna from Kovran sediments of the western shore of Kamchatka between promontory Nepropusk and the mouth of Etolon River at the base of Etolon suite, in three layers, with a general thickness of about 40 mm, 25 specimens of this species were found, among which there was one bivalved. In the collection the large shells were predominant. The material allowed a reconsideration of the species as belonging to subgenus Chlamys and ascribing it to subgenus Nanaochlamys Hatai and Masuda, 1953.
The following features are used as the main basis. They are well represented in the specimens of our collection. In the right valve of the species, dichotomic broad ribs are well developed, actually much narrower than in N. rotoensis. In N. notoensis, dichotomic ribs are developed on all the surface of the disk, and in N. anapleus, only on the apex and rarely on the surface of the disk. On the left valve in N. notoensis and in N. anapleus, the number of the main ribs is similar, but the number of the additional ribs and the width difference between the main ribs and the additional radial ribs in N. anapleus is not so great, as in N. notoensis. Pseudohinged apparatus of both species is identical (pl. XVI, fig. 8). Moreover, on the left valve, the concentric step-folding is well observed, which is accompanied with developed nodulars in the large radial ribs. On the right valve, step-like stage is less marked. Both valves are covered with well represented alveolated microsculpture, which is well preserved in the auricles and intercostal intervals.
Ctenolium is well-developed only in the younger sheIls. In the adult forms, it is not clear. Sometimes it is in the form of small 2 or 1 knobs near the fasciole. In the internal side of the shell, there are reflected double-upper ribs with a moderate groove. The concentric-reflected ribs distinctly differentiate "Chlamys" anapleus from the typical represented genus Chlamys and refer to its assigning to genus Nanaochlamys.»
SINELNIKOVA, V. N. 1975. Mio-Pliocene Pectinidae of Kamchatka. Transactions of the Geological Institute, Academy of Sciences of the USSR, 229: 1-140, 25 pls. (in Russian with English title and contents; Translated for the U. S. Department of the Interior, Geological Survey, and the National ScienceFoundation, Washington, D. C., by the Al-Ahram Center for Scientific Translations, 1977). [p. 83, 84]
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Nanaochlamys anapleus (Woodring); V. N. Sinelnikova, 1975, Mio-Pliocene Pectinidae of Kamchatka, plate 14, figures 1a, 1b; plate 16, figures 1, 2a, 2b; plate 25, figures 1, 3, 4, 6, 8.
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«29. Pecten (Chlamys) hericeus var. strategus Dall.
PLATE XI, FIG. 5. Pecten hericeus var. strategus Dall, Trans. Wagner Inst. Sci., Vol. Ill, Part 4, 1898, p. 709.
Shape and general texture same as P. hericeus. "The fasciculi of the left valve, to the number of five to seven, with the riblets coalescent, forming large, smooth-backed, turgid ribs, with smaller imbricate intercalary threads. The large ribs sometimes break up suddenly into the usual small riblets near the base. The recent specimens are bright scarlet." (Dall). The right valve of a young from the Pleistocene of Deadman Island shows nine fasciculi, most of which seem to be made up of two riblets which keep their individuality to the umbo, instead of coalescing; the interspaces are slightly narrower than the fasciculi. The anterior ear of this right valve is prominent and ornamented with six radiating ribs, and near the disk, by elevated lines of growth; byssal notch rather deep; whole surface ornamented with minute, lattice-like sculpture.
Dimensions.— Long. 18 mm.; alt. 21 mm.; diam. 5.2 mm.; hinge 9.4 mm. Distinguishable by the few prominent, sulcated ridges, and smooth surface, except for minute sculpture. Specimens identified by Dr. Dall. Two specimens from the lower San Pedro series of Deadman Island, one of which is figured, and is now in the collection of Delos Arnold. Living.— Unalaska (Dall). Pleistocene.— Alaska (Dall): San Pedro (Arnold).» ARNOLD, R. 1903. The Paleontology and Stratigraphy of the Marine Pliocene and Pleistocene of San Pedro, California. Memoirs of the California Academy of Sciences, 3: 1-420, pls. 1-37. [p. 110, 111]
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Pecten (Chlamys) hericeus var. strategus Dall; R. Arnold, 1903, The Paleontology and Stratigraphy of the Marine Pliocene and Pleistocene of San Pedro, plate 11, figure 5.
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