Euthymipecten beaveri (J. Sowerby, 1817)
SOWERBY, J. & J. DE C. SOWERBY. 1812-1846. The Mineral Conchology of Great Britain; or coloured figures and descriptions of those remains of testaceous animals or shells. 7 vols., pls. 1-648 (and 2 bis). London. [vol. 2, p. 131, pl. 158]
1817 Pecten beaveri J. Sowerby, 1817
1833 Pecten depressus Münster in Goldfuss, 1833
1850 Pecten jugosus J. de C. Sowerby in Dixon, 1850
1833 Pecten depressus Münster in Goldfuss, 1833
1850 Pecten jugosus J. de C. Sowerby in Dixon, 1850
J. Sowerby & J. de C. Sowerby. 1812-1846, plate 158.
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«SPEC. CHAR. Depressed, orbicular, smooth, with irregular longitudinal costae; ears as wide as the shell, nearly equal.
The costae vary in size and distance in the same shell, and there are between the principal ones now and then a small one or two: the shell is thin. Among many specimens I have not seen so perfect an example to identify the species as this, lent me from the Oxford Museum, to which Mr. Beaver presented it; it is from the Rev. Mr. Beaver's quarry at Childrey, near Wantage, Berkshire. I take advantage of the opportunity thus allowed me of publishing the species; at the same time I beg leave of my friends and correspondents to say, that I shall still be glad of information or specimens, as it is very irregular in some of its characters, and the outside is as yet but imperfectly known. I have specimens of the same from Hamsey, Sussex, which Mr. Mantell kindly sent me, that identify a similar stratum (Chalk marl), but the shells being more mutilated and smaller, may indicate something relating to its age. The upper figure is from an impression of the shell taken in clay; I have been able to seperate a portion of the shell from a Hamsey specimen, sufficient to shew that it is smooth: this figure, therefore, exhibits the outside: the lower figure shews the inside of the shell which adheres by its outside to the stone, or rather hard marley chalk, in which it lies. There are a few spots of pyrites about it.» JAMES SOWERBY, 1817
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«Brief description. All specimens represent large, suborbicular, compressed, nearly equivalved and almost equilateral pectinids; ornament of internal moulds consisting of broad irregular radial primary ribs with frequent intercalated secondaries and tertiaries. Intercostal intervals mostly wider than rounded ribs; concentric elements may subdivide ribs (Fig. 6H). Auricles unequal and elongated to narrowly triangular; small portions of relatively thin shell preserved in specimens DZ-W-L2 and BGR-Ma13959 (Fig. 6A, B).
Remarks. In England, this species is known from fine-grained sediments of AlbianeEarly Cenomanian age; E. beaveri resembles E. astierianus from the lower Lower Cretaceous (see Dhondt and Dieni, 1988).»
WILMSEN, M., B. NIEBUHR, C. J. WOOD & D. ZAWISCHA. 2007. Fauna and palaeoecology of the Middle Cenomanian Praeactinocamax primus Event at the type locality, Wunstorf quarry, northern Germany. Cretaceous Research, 28: 428-460, figs. 1-12. [p. 441]
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Euthymipecten beaveri (J. Sowerby, 1817); M. Wilmsen, B. Niebuhr, C. J. Wood & D. Zawischa, 2007, Fauna and palaeoecology of the Middle Cenomanian Praeactinocamax primus Event at the type locality, Wunstorf quarry, northern Germany, figures 6A, 6B, 6H, 6I.
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«Description.— Shell large, thin, oval or nearly circular; height usually slightly greater than Iength; margins evenly rounded except at the junction with the ears. Valves compressed, nearly equal, slightly inequilateral. Apical angle large, from 118º to 125º. Ears long, low, a little unequal.
Right valve with broad radial ribs, which have sharp and sometimes slightly irregular summits and gently sloping sides; there are also similar smaller ribs, which do not reach the umbo. The ribs are smaller anteriorly and posteriorly. The surface of the valve is ornamented with fine, close-set, concentric, linear ridges, and sometimes with radial ridges. Anterior ear with a well-marked sinus, ornamented with scaly ribs except near its junction with the valve. Posterior ear smaller, outer angle nearly a right angle; surface with ribs, sometimes obscured by concentric lamellae. Left valve with about seventeen main ribs, which are narrow, elevated, and sharp, sometimes slightly serrate at the summits; separated by broad furrows. A smaller rib is often introduced in the middle of the furrow at a distance from the umbo, and on the sides of the ribs other still smaller ribs may occur. Anteriorly and posteriorly the main ribs become smaller. The ribs and furrows are crossed by many fine, close-set, regular, concentric ridges, which are seen most distinctly in the furrows. Anterior ear a little more elevated than the posterior; both with radial ribs and sharp outer angles. Measurements:
(1) (2) (3) (4) (5) (6) Length 81 86 88 106 96 109 mm Height 80 88 101 106 98 109 "
Affinities.— P. depressus, Goldfuss, seems to be scarcely distinguishable from P. Beaveri. The specimen figured by Goldfuss as P. beaveri does not show the small ribs on the sides of the main ribs, and may perhaps be distinct, but this can be determined only by an examination of specimens.
Types.— The type was obtained from Lower Chalk of Childrey, near Wantage, and is said to be in the Oxford Museum. The type of P. jugosus is missing, and the locality from which it was obtained is not given by Sowerby. Mantell's figured specimen, from the Chalk Marl of Hamsey, also appears to have been lost. Distribution.— Upper Gault (zone x) of Folkestone. Red Limestone of Hunstanton (fide Survey Memoirs). Chloritic Marl of Blackgang and Niton. Chalk Marl of Ventnor, Folkestone, Meldreth, Hunstanton, Stoke Ferry, etc. Totternhoe Stone of Cherry Hinton, Burwell, Dersingham, and Hunstanton. H. subglobosus zone of Blue Bell Hill (Burham), Shelford, and Cherry Hinton.» WOODS, H. 1902-1903. A monograph of the Cretaceus Lamellibranchia of England. Vol. I. Paleontological Society Monograph. Part IV Pectinidae,pp. 145-196 (1902); Part V Pectinidae (continued), pp. 197-232 03). The Paleontographical Society (First reprinting, 1975: Vol. 56 nº 264 and Vol. 57 nº 267). [p. 189, 190]
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Pecten (Aequipecten) Beaveri Sowerby, 1817; H. Woods, 1902-1903, A monograph of the Cretaceus Lamellibranchia of England, plate 38.
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