Plesiopecten Munier-Chalmas in Fischer 1886
FISCHER, P. 1880-1887. Manuel de conchyliologie et de paléontologie conchyliologique, ou histoire naturelle des mollusques vivants et fossiles. 1369 p., pls. 1-23. Librairie F. Savy. Paris. [p. 944]
«— Pseudopecten, Bayle. 1879. Oreillettes égales; côtes rayonnantes fortes et lisses (C. aequivalvis, Lamarck. Lias).
S. g. Plesiopecten, Munier-Chalmas. 1886. — Charnière de Spondylus; aréa du ligament épidermique triangulaire, striée verticalement; forme et ornements de Chlamys. Distribution. Terrains jurassiques (P. subspinosus, Schlotheim).» ERNEST MUNIER-CHALMAS IN PAUL FISCHER, 1886
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Pecten subspinosus Schlotheim; A. Goldfuss,1833-1840, Petrefacta Germaniae, pIate 100, figures 4a-4c.
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«The fossil record indeed provides evidence that Spondylopecten appeared earlier than Spondylus. Johnson (1984: 82,85) established that Spondylopecten s.s. and Spondylopecten (Plesiopecten) Munier-Chalmas (in Fischer, 1886) were definitely present by the beginning of the Middle Jurassic (Aalenian stage), but was cautious about interpreting reports of earlier occurrences from the Lower Jurassic (Hettangian stage). It can now be reported, however, that Spondylopecten (Plesiopecten) was already present in the Late Triassic. Specimens that appear to belong to this taxon were discovered by the author in the Mesozoic stratigraphic collections of the Smithsonian Institution. They are part of a coarsely silicified fauna from near Hall Creek, near the 40th parallel in the northern Toiyabe Range of west-central Nevada. This Triassic outcrop was first discovered by Stewart in 1969 and is shown on the geological map of Lander County, Nevada by Stewart & McKee (1977). The fauna of molluscs, brachiopods, corals, and sponges has not yet been studied in its entirety, but Nichols & Silberling (1977: 60) thought that a trachyceratid ammonoid from these beds indicated a latest Ladinian or earliest Carnian age. The bivalves, however, suggest a younger age. In comparison with a Middle Triassic (late Ladinian) fauna recently described from the New Pass Range of Nevada (west of Toiyabe Range) by Waller & Stanley (2005) and with an early Norian fauna described from Hells Canyon, Oregon (approximately 300 miles to the north of the Hall Creek locality) by Newton et al. (1987), the Hall Creek bivalves are more like those at the latter locality.»
WALLER, T. R. 2006. Phylogeny of families in the Pectinoidea (Mollusca: Bivalvia): importance of the fossil record. Zoological Journal of the Linnean Society, 148: 313-342, figs. 1-12. [p. 334]
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«When establishing the family Spondylopectinidae Kasum-Zade et Romanov, 1987 (Kasumzade and Romanov, 1987) included within this family were both subfamilies Spondylopectininae (genera Spondylopecten Roeder, 1882 and Plesiopecten Munier-
Chalmas, 1886) and Radulopectininae. Within the composition of the subfamily Radulopectininae, besides the genera shown in L.F. Romanov’s work (1985), the genera Indopecten Douglas, 1929 and Praespondylopecten Romanov, 1987 were included. The combination within the composition of one family of taxa with different hinge structures is incorrect, and hence, almost simultaneously (Kasumzade, 1987 and 1989) the subfamily Spondylopectininae Kasum-Zade et Romanov was established by us with two genera: Spondylopecten Roeder, 1882 and Plesiopecten Munier-Chalmas, 1886. K. V Dykan’ (Dykan’ and Makarov, 1990) supports an analogous point of view, which removes representatives of Radulopectininae from the family Spondylopectinidae Kasum-Zade et Romanov, 1987, and the genera Radulopecten Rollier, 1911, Minervapecten Romanov, 1985, Pamiropecten Romanov, 1985 are considered to be in the family Chlamydidae.» KASUM-ZADE, A. A. 2003. Advance in research of mesozoic bivalve mollusks in Azerbaijan (Order Pectinoida: Revision and Systematics). 111 pp. Baku (in Russian; translated by Rosanne D’Aprile Johnson, VIARC, Smithsonian Institution). [p. 53]
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«Within the toothed Jurassic pectinids two distinct subgroups may be recognised. One has numerous rounded plicae bearing 2-4 rows of spines while the other has fewer, more angular plicae bearing single rows of spines. There is no direct evidence to suggest that one group has evolved from the other and the fact that teeth have been acquired polyphyletically in various Cenozoic 'Chlamys' species (de Loriol, 1901; ARKELL, 1935a) indicates that there are only grounds of convenience for uniting the two groups of toothed Jurassic pectinids within the same genus. They are herein separated at the subgeneric level; the former group being referred to S. (Spondylopecten) and the latter to S. (Plesiopecten). Plesiopecten MUNIER-CHALMAS was considered by HERTLEIN (1969) to be synonymous with Spondylopecten Roeder at the generic level. However, apart from the obvious differences in form of the type species (respectively typical and sole species of the two groups delineated above), it has been shown by ARKELL (1935a) that ROEDER's original conception of Spondylopecten did not include the type species of Plesiopecten (cf. p. 90). There are thus ample grounds for employing Spondylopecten and Plesiopecten as separate subgeneric categories.»
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. 83]
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