Pecten praevasseli de Böckh & Richardson in Douglas, 1928
DOUGLAS, J. A. 1928. Contributions to Persian Palaeontology, III. 19 p., pls. 8-15. The Anglo-Persian Oil Company Lts. Printed at The Holywell Press, Oxford [p. 6, pl. 10, figs. 3, 4]
1928 Pecten praevasseli de Böckh & Richardson in Douglas, 1928
J. A. Douglas, 1928, plate 10.
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«Shell very inequivalve. Right valve moderately convex, ornamented with a variable number of prominent radial ribs; rounded in cross-section, which bifurcate near the umbo and again a short distance down the shell, the riblets thus formed remaining grouped in bundles of four. Each bundle is separated from its neighbour by an interspace relatively wider than those between individual ribs and bearing a single subsidiary rib which originates some distance away from the umbo. The forked ribs occasionally show further dichotomy near the ventral border.
Ears large, the posterior bearing three or four widely spaced fine, radial costae. Left valve flat, with numerous irregularly spaced ribs; the larger ones radiating from the umbo, the smaller intercalated between them. Ears subequal, the posterior bearing nine or ten, fine, radial striae. Remarks. This species was first recorded by Dr. H. de Böckh and his colleagues from Qishm Island in the Persian Gulf, who remarked that the distinctive nature of its ribbing showed that it was closely related to, if not the ancestral form of, Pecten vasseli Fuchs. The specimens so far available, however, are fragmentary and ill-preserved, and although a broken left valve 57 mm. in height shows that the examples figured here are not of full size, this Miocene shell probably never attained the dimensions of that species. Horizon. Considerably below that of the true P. vasseli beds, in a limestone of Miocene age probably about the horizon of the Ostrea virleti beds of the Middle Fars series.» JAMES ARCHIBALD DOUGLAS, 1928
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«Material:— Sample Qm.966 (Qishm Island, Salakh dome, S. flank; M. Miocene, 400 ft. above base), 5 specimens (including L.86153-4).
Description:-- Known only by left valve, which is flat or slightly concave. Antero-dosal margin straight, postero-dorsal margin slightly concave, their angle of divergence increasing from about 90° to about 105°. Posterior ear large, almost right-angled, with up to 9 narrow riblets of variable strength. Anterior ear large, slightly concave, its outer angle slightly less than 90°, and with up to 7 narrow riblets, its surface bearing fine growth-threads. Numerous narrow, very projecting, rounded ribs, about 6 of which are most prominent and deeply grooved after mid-growth and have intervals with secondary ribs of two orders; the numbef of ribs at the margin is about 32. Internal marginal region grooved according to the ribbing. Dimensions:— H = 36.5 mm. (slightly incomplete). L = 41.3 mm. Remarks:-- Douglas gave a brief description of, but did not illustrate, the left valve of P. praevasseli. Their ornament and internal appearance leave little doubt that the specimens described above are left valves of this species, but, since they are not associated with right valves, the identification is qualified.» EAMES, F. E. & L. R. COX. 1956. Some Tertiary Pectinacea from East Africa, Persia, and the Mediterranean region. Proceedings of the Malacological Society of London, 32 (1): 1-68, pls. 1-20. [p. 36]
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Pecten cf. praevasseli Douglas, 1928; F. E. Eames & L. R. Cox, 1956, Some Tertiary Pectinacea from East Africa, Persia, and the Mediterranean region, plate 14, figure 3.
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