Pernopecten obliquus Girty, 1908
GIRTY, G. H. 1908. The Guadalupian Fauna. United States Geological Survey Professional Paper, 58: 1-651, pls. 4-31. [p. 441, pl. 9, figs. 13, 13a, 14, 14a]
1908 Pernipecten? [sic] obliquus Girty, 1908
G. H. Girty, 1908, plate 9.
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«Shell small, elongate, nearly flat. Hinge line shorter than the width below. In the left (?) valve the two ears are nearly equal, small, and moderately well defined both in outline and by grooves on the surface. The shell expands considerably below them, and is gently inclined backward ( ?). The superior portion is more or less turned upward at the sides along two converging lines.
The surface is rather regularly marked by delicate concentric striae. Only one valve seems to be represented in our collections, and the foregoing description is applicable to about half a dozen specimens from the Capitan limestone, but all of them are, unfortunately, imperfect. The smooth surface, the low convexity, and the upturned margins of these shells seem to ally them with Entolium and Pernipecten; but the obliquity of the axis and the small extension of the ears, if, indeed, the shape is that which seems to be indicated by my imperfect material, are unusual among those forms. The low convexity of these shells would distinguish them from any of the other pectinoids of this horizon except Aviculopecten infelix, even if the sculpture and conformation did not offer additional characters for discrimination. A single imperfect example from the Delaware Mountain formation has been provisionally referred to the same species. Horizon and locality.— Middle of Capitan formation, Capitan Peak (station 2926); Delaware Mountain formation, Guadalupe Point (station 2931), Guadalupe Mountains, Texas. Delaware Mountain formation, southern Delaware Mountains, Texas (station 2935).» GEORGE HERBERT GIRTY, 1908
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«I have had the privilege of studying Doctor Girty's type specimen, and from microscopic examination of the specimen under xylol it appears to me that the shape indicated by Girty's fig. 13 is incorrect. The auricles extend high above the hinge, as is normal in the genus.
The species appears to be a small one, comparable in size to P. ohioensis, and would be difficult to identify in the absence of good material. However, it appears to have a rather distinctive posterior profile, being somewhat more produced posteriorly than P. ohioensis and, uniike that species, lacks a well-defined posterodorsal shoulder or lobation of the margin below the rear auricle. Right vale unknown. Material.— I have seen only the holotype of the species and one topoparatype, both left valves, the two figured by Girty. They bear the catalogue numbers 405, 406. Found in olomitic limestone.
Occurrence.— Upper Permian, Capitan limestone, Guadalupe Mountains, western Texas.»
NEWELL, N. D. 1938. Late Paleozoic Pelecypods: Pectinacea. State Geological Survey of Kansas, 10: 1-123, pls. 1-20. [p. 113]
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Pernopecten obliquus Girty; N. D. Newell, 1938, Late Paleozoic Pelecypods: Pectinacea, plate 20, figures 15, 16.
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