Camptonectes Agassiz in Meek, 1864
MEEK, F. B. 1864. Checklist of the invertebrate fossils of North Amer- ica: Cretaceous and Jurassic. Smithsonian Miscellaneous Collections, 177, Bivalvia: 5-16, 31-34. [p. 39]
«CAMPTONECTES, AGASSIZ MSS. Example Pecten lens, SOWERBY. Also includes Pecten bellistriatus, Meek, Proc. Acad. Nat. Sci. July, 1860, 311.
The name Camptonectes has been adopted by Prof. Agassiz for a group of Jurassic and Cretaceous species, several of wliich have been confounded under the name Pecten lens. These shells are subequivalve, compressed, lenticular, and closed all around. They have generally small compressed ears, and a short edentulous hinge; byssal sinus under the anterior ear of right valve deep, well defined. Surface ornamented with fine, very regular, closely arranged, often sub-punctate, radiating or sub-divaricate striae, which curve gracefully outwards on each side. This genus is known to be represented by at least one undescribed species in the Cretaceous beds of New Jersey. It will include a few species, such as Pecten cottaldinus, D'Orbigny, upon which the radiating striae are nearly or quite obsolete.» FIELDING BRADFORD MEEK, 1864
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Pecten lens; J. Sowerby & J. de C. Sowerby, 1812-1846, The Mineral Conchology of Great Britain, plate 205, figures 2, 3.
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Camptonectes (C.) subulatus (Münster, 1836); A. L. A. Johnson, 1984, The palaeobiology of the bivalve families Pectinidae and Propeamussiidae in the Jurassic of Europe, plate 4, figures 3-5, 7, 8.
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«Genus CAMPTONECTES Agassiz in Meer 1864
Type species. SD; Stoliczka 1871, p. 425; Pecten lens J. SOWERBY 1818, p. 3, pl. 205, figs. 2, 3; Corallian Beds (Oxfordian) of the Oxford district.
AMENDED diagnosis
Part or all of exterior ornamented with fine, oblique, divergent, curved, crenulated, commonly punctate striae and concentric lines or raised laminae. L. Jur. - U. Cret., cosmop.
DISCUSSION
Hertlein's (1969: N351) diagnosis for Camptonectes has been slightly altered so as to expressly include forms (e. g. C. (C.) subulatus, C. (Camptochlamys) clathratus) which only have the distinctive divaricate ornament on a small part of the shell. Such forms are undoubtedly related to the more typical members of the genus well provided with divaricate ornament. Examples of C. (C.) subulatus which possess only a small byssal notch (e. g. Pl. 4, Fig. 7) closely resemble the contemporaneous species Entolium (E.) lunare. They may, however, be distinguished by the features described on p. 35 thus there is little evidence to support STAECHE's (1926: 55) contention that Camptonectes and Entolium are convergent in the L. Jurassic.»
JOHNSON, A. L. A. 1984. The palaeobiology of the bivalve families Pectinidae and Propeamussiidae in the Jurassic of Europe. Zitteliana, 11: 1-235, pls. 1-11. [p. 106, 107]
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Camptonectes (Camptonectes) auritus (Schlotheim, 1813); K. L. Duff, 1978, Bivalvia from the English Lower Oxford Clay (Middle Jurassic), plate 5, figures 22a, 22b, 25.
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«Genus CAMPTONECTES Agassiz in Meek, 1865
Type species. Subsequent designation; Stoliczka 1871, p . 425; Pecten lens J. Sowerby 1818, p. 3, pl. 205, figs. 2, 3 ( = Chamites auritus Schlotheim 1813, p. 103); Corallian Beds of the Oxford district.
Diagnosis. Inequivalve, left valve more inflated than right; large byssal notch developed beneath right anterior auricle; ornament of fine curved divaricate striae, a punctate pattern being produced by their intersection with fine concentric growth lines.» DUFF, K. L. 1978. Bivalvia from the English Lower Oxford Clay (Middle Jurassic). Palaeontographical Society. Monograph 553: 1-137, pls. 1-13. [p. 65]
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