Maclearnia broenlundi (Ravn, 1910)
RAVN, J. P. J. 1910. On Jurassic and Cretaceous fossils from North-East Greenland. Meddelelser om Grønland, 45: 437-500, pls. 32-38. Reprinted from Meddelelser om Grønland, Bianco Luno, Copenhagen, 1911. [p. 465, pl. 34, figs. 5, 6]
1910 Pecten (Camptonectes) broenlundi Ravn, 1910
J. P. J. Ravn, 1910, plate 34.
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«Large, circular Bivalve with very unequal valves. Angle at the umbo ca. 120º.
Left valve strongly arched; ears fairly small, not reaching over the cardinal margin and not very sharply distinct from the rest of the valve; the outer corner of both ears forming a blunt angle. Right valve almost perfectly flat; outer corner of its posterior ear almost a right angle; anterior ear not seen. — The surface of both valves with numerous line and a few coarse lines of growth, and crossing these almost at right angles characteristic, somewhat undulating, fine, deepened lines, which are frequently interrupted especially by the stronger lines of growth. Under the lens other, very line, depressed lines, usually cutting the first-named, radial lines at a very pointed angle. The sculpture stronger on the wings and in the neighbourhood of these, of a characteristic, papillose character. Left valve: height 99 mm, breadth 97 mm and thickness ca. 18 mm; length of cardinal margin ca. 45 mm. In the light-gray sandstone from the top of Muschelberg on Hochstetter's Foreland some imprints were found of a large Pecten, which from their whole form might well belong to the same species as the above; unfortunately, small crystals of quartz have been secreted on the imprints, so that it is impossible to determine the nature of the surface of the valves. Thus, a certain determination cannot be made. This applies also to a cast found in a boulder on the south side of Vesterdalen at Danmarks Havn. It seems, however, to be distinct from P. Broenlundi, having a somewhat broader outline, a more pointed umbo and unusually flat lateral portions. It is thus even more doubtful, if this specimen can be placed under this species. The form described resembles somewhat P. imperialis Keys., both in form and especially sculpture. It is readily distinguished from this, however, among other characters, by both its valves (and especially the right valve) being considerably less arched; further, its cardinal margin is relatively much shorter. P. Broenlundi has greater resemblance to P. validus Lindstr., but its left valve is more strongly arched, and the front margin below the anterior ear of the right valve has a somewhat different form, its concavity being considerably fainter than is the case in P. validus. Distribution. North-East Greenland: "Kløft I" on Store Koldewey Island (9 spec). — ? Top of Muschelberg on Hochstetter's Foreland (3 spec). — ? In a boulder from the south side of Vesterdalen at Danmarks Havn (1 spec).» JESPER PETER JOHANSEN RAVN, 1910
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«The oldest species of Mclearnia thus far described, Mclearnia broenlundi (Ravn, 1911), occurs in the middle Ox- fordian of east Greenland (Fiirsich, 1982), and differs from later occurring Mclearnia in having a narrower umbonal angle, a less flattened right valve, and a smoother shell without well-devel- oped commarginal flanges. None of the Mclearnia species are known to have radial costae.»
WALLER, T. R. & L. MARINCOVICH JR. 1992. New species of Camptochlamys and Chlamys (Mollusca: Bivalvia: Pectinidae) from near the Cretaceous/Tertiary boundary at Ocean Point, North Slope, Alaska. Journal of Paleontology, 66 (2): 215-227, figs. 1-5. [p. 220]
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