Pernopectinidae Newell, 1938
NEWELL, N. D. 1938. Late Paleozoic Pelecypods: Pectinacea. State Geological Survey of Kansas, 10: 1-123, pls. 1-20.
«A small, compact group of pectinids having approximately the form and hinge characters of the modern Amussium is recognized from the Late Devonian or Early Carboniferous to the present time. The correspondence between the Paleozoic Pernopecten and the modern Amussium is rernarkably close. The geologic history of the tribe of Pernopecten is quite different from that of the Pectinidae. The existence of a true Pecten in the Paleozoic has never been demonstrated, notwithstanding the nurnerous citations of the genus frorn the Permian. Only Pernopecten had a ligament like that of the modern Pectinidae and had acquired that kind of ligament as early as Early Carboniferous time. It scarcely seems probable that Pernopecten gave rise to the Pectinidae, however, in spite of the apparent identity of the ligament system in the two. The equivalve form, gaping valves, and obsolete byssal notch of Pernopecten suggests that it was highly specialized rather than a primitive type, and it appears probable that the Pectinidae had their origin in the Aviculopectinidae, possibly during the late Permian or Triassic.
The probable phylogeny of the Paleozoic Amussiidae is indicated in figure 17.»
NORMAN DENNIS NEWELL, 1938
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Table III [Inset]. Proposed Classification of Paleozoic Pectinacea.
Carboniferous and Jurassic Amussiidae, Pernopecten; N. D. Newell, 1938, Late Paleozoic Pelecypods: Pectinacea, plate 20, figures 1-18.
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T. R. Waller, 2006, Phylogeny of families in the Pectinoidea (Mollusca: Bivalvia): importance of the fossil record, figure 3.
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«The family Pernopectinidae ranges stratigraphically from Upper Devonian (upper Famennian of Germany; Amler, 1995) to lowermost Triassic (Griesbachian of Salt Range region, Pakistan; Nakazawa, 1996) (see also Appendix 4) and attained its worldwide distribution and maximum species diversity in the Carboniferous. There is therefore no stratigraphic contradiction to the hypothesis that pernopectinids evolved from euchondriids in Late Devonian time and gave rise to the Entolioididae, new family, in the Early Triassic.
[...]
APPENDIX 3
The family Pernopectinidae is regarded herein as tentatively monogeneric. At least some of the Palaeozoic species previously placed in Syncyclonema or Entolium appear to be Pernopecten. I agree with Astafieva-Urbajtis (1977) that Protoentolium Yanishevski, 1960 distinguished on the basis of the presence of a filosus structure and a left anterior auricle with deeper scrolling than the posterior auricle, is a junior synonym of Pernopecten. Without citing Astafieva-Urbajtis (1977), Romanov (1985) regarded Protoentolium as valid and named a new family Protoentoliidae containing it and Pernopecten. I am unable to confirm the differential enlargement of the left anterior scroll on the type species of Protoentolium and tentatively regard it as an artefact of the breakage of the scroll on the posterior side. The family name Protoentoliidae, because it contains the genus Pernopecten, is a junior synonym of Pernopectinidae Newell, 1938.
APPENDIX 4
Other reports of Triassic Pernopecten may not be well founded. Ling (1988) reported a new species, Pernopecten dictyoformis from the Lower Triassic Yidaohe Formation of China, but his illustrations indicate that this species probably belongs in the Entolioididae, possibly in the genus Entolioides Allasinaz, 1972.»
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. 318, 319, 341, 342]
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