Camptochlamys clathrata (Roemer, 1836)
ROEMER, F. A. 1836. Die Versteinerungen des Norddeutschen Oolithen-Gebirges. 218 p., pls. 1-16. Hannover. [p. 212, pl. 13, fig. 9]
1836 Pecten clathratus Roemer, 1836
1839 Pecten intertextus Roemer, 1839
1842 Pecten collineus Buvignier in Sauvage & Bouvignier, 1842
1850 Pecten rosimon Orbigny, 1850
1852 Pecten michaelensis Buvignier, 1852
1853 Pecten retiferus Morris & Lycett, 1853
1862 Pecten frotei Étallon in Thurmann & Étallon, 1862
1862 Pecten pertextus Étallon in Thurmann & Étallon, 1862
1923 Chlamys lafayi Lissajous,1923
1931 Pecten (Chlamys) pertextus var. densiradiatus Sokolov & Bodylevsky, 1931
1839 Pecten intertextus Roemer, 1839
1842 Pecten collineus Buvignier in Sauvage & Bouvignier, 1842
1850 Pecten rosimon Orbigny, 1850
1852 Pecten michaelensis Buvignier, 1852
1853 Pecten retiferus Morris & Lycett, 1853
1862 Pecten frotei Étallon in Thurmann & Étallon, 1862
1862 Pecten pertextus Étallon in Thurmann & Étallon, 1862
1923 Chlamys lafayi Lissajous,1923
1931 Pecten (Chlamys) pertextus var. densiradiatus Sokolov & Bodylevsky, 1931
F. A. Roemer, 1836, plate 13.
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«20. Pecten clathratus NOB. - Tab. XIII. Fig. 9.
P. testa lineis capillaribus acutis radiantibus rectis concentricisque regulariter clathrata, interstitiis planis quadratis. Die ziemlich dünne Schale scheint fast kreisrund gewesen zu sein und trägt oben zahlreiche, haarförmige, schief in die Höhe gerichtete, gleich weit von einander stehende Linien, von denen gerade ausstrahlende mit concentrischen ein sehr zierliches, feines Gitterwerk bilden. Die viereckigen, meist mehr breiten als hohen Flächen zwischen den Linien sind ganz flach. Das abgebildete Bruchstück fand sich im oberen Coral rag des Spitzhuts mit Terebr, tetragona und Turbo princeps zusammen.» FRIEDERICH ADOLPH ROEMER, 1836
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2. AMENDED DIAGNOSIS
«Distinguished from C. (Cc.) obscurus by the fact that the radial Striae reach the ventral margins at all stages in ontogeny.
3. AMENDED DESCRIPTION
Essentially similar to C. (Cc.) obscurus apart from the diagnostic feature (see Section 2), possibly somewhat higher mean H/UA (text fig. 132), apparent allometric decrease in AH/Land I L/L (textfigs. 134, 133), Iower comarginal lamellae and usual lack of divaricate striae (see p. 133). There are between 33 and 45 radial striae on the left valve and between 45 and 68 on the right valve (PI. 4, Figs. 23, 26, 27, PI. 5. Figs.
1-3, 6). Other metric proportions are plotted in text figs. 131, 135. 4. DISCUSSION
As for C. (Camptochlamys) obscurus the disjunct stratigraphic range of the species described in Section 3 combined with a failure to appreciate the ränge of ornamental Variation has led to the evolution of two taxonomic schemes for M. and U. Jurassic representatives. ARKELL (1930a) considered that Oxfordian specimens (referred to 'Chlamys' (Cc.) intertextus (ROEMER)) differed from Bathonian specimens (referred to 'Ch.' (Cc.) retiferus (MORRIS and LYCETT)) by the possession of 45-50 compared with 35-40 radial Striae. Since ARKELL failed to recognise the disparity in numbers of striae between right and left valves this gives an incomplete picture of variation. However, if one assumes that counts were taken only
from left valves, as seems likely , then the existence of Oxfordian specimens with 40 striae (e. g. YM 557) and Bathonian specimens with 45 striae (e. g. BM 65901) clearly contradicts ARKELL's hypothesis. Metric proportions offer no other grounds for a distinction, the larger Oxfordian forms plotting within the ränge of extrapolated Bathonian ontogenies (text figs. 131-135). Moreover the figured original of 'Pecten' intertextus ROEMER, although only a broken speeimen, is mdistinguishable from the lectotype of 'P. ' retiferus MORRIS and LYCETT (IGS 9169; PI. 4, Fig. 26).» 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. 145, 146]
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Camptonectes (Camptochlamys) clathratus (Roemer 1836); A. L. A. Johnson, 1984, The palaeobiology of the bivalve families Pectinidae and Propeamussiidae in the Jurassic of Europe, plate 4, figures 23, 26, 27; plate 5, figures 1-3, 6.
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