Hinge grades in the evolution of crassatellacean bivalves as revealed by Permian genera. American Museum novitates ; no. 2328

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dc.contributor.authorBoyd, Donald Wilkin.en_US
dc.contributor.authorNewell, Norman Dennis, 1909-en_US
dc.date.accessioned2005-10-06T16:28:50Z
dc.date.available2005-10-06T16:28:50Z
dc.date.issued1968en_US
dc.description52 p. : ill. ; 24 cm.en_US
dc.descriptionIncludes bibliographical references (p. 50-52).en_US
dc.description.abstract"The origin and affiliation of the conservative bivalve superfamily Crassatellacea FĂ©russac, 1882 (= Astartacea d'Orbigny, 1844), have been uncertain. Some authors have regarded these mollusks as lucinoids. Others have placed them with the cyrenoids, or in a separate order of the Heterodonta, the 'Astartedonta.' Our discovery of numerous exceptionally well-preserved examples of the Crassatellacea of Permian age in Wyoming clarifies some problems of the early history of the group, showing how, by the acquisition of additional hinge teeth after Permian time, the hinge of living crassatellaceans became modified in separate lines from basically lucinoid to a more advanced hinge grade. Representatives of post-Paleozoic Crassatellidae and Astartidae through convergent evolution resemble one another more closely than do their Paleozoic ancestors, the new subfamilies Oriocrassatellinae and Astartellinae. Members of these Paleozoic subfamilies are sufficiently dissimilar to suggest a diphyletic origin for the Crassatellacea. The Bernard and Munier-Chalmas hinge formula and its implication of dental homologies are discussed, and a simplified, more objective hinge notation based on the Steinmann system is employed. Two new species, Oriocrassatella elongata and Astartella aueri, are described. Examples of hinge transposition of cardinal and anterior lateral teeth, but not the posterior laterals, are recorded in both. This partial transposition of hinge teeth, recorded for the first time in Paleozoic bivalves, indicates that the posterior laterals are genetically independent of the other hinge teeth"--P. [1]-2.en_US
dc.format.extent8048284 bytes
dc.format.mimetypeapplication/pdf
dc.identifier.urihttp://hdl.handle.net/2246/2538
dc.languageengen_US
dc.language.isoen_US
dc.publisherNew York, N.Y. : American Museum of Natural Historyen_US
dc.relation.ispartofseriesAmerican Museum novitates ; no. 2328en_US
dc.subject.lccQL1 .A436 no.2328, 1968en_US
dc.subject.lcshOriocrassatella elongata.en_US
dc.subject.lcshAstartella aueri.en_US
dc.subject.lcshCrassatellidae, Fossil -- Wyoming -- Wind River Range.en_US
dc.subject.lcshMollusks, Fossil -- Wyoming -- Wind River Range.en_US
dc.subject.lcshCrassatellacea -- Evolution.en_US
dc.subject.lcshPaleontology -- Permian -- Wyoming -- Wind River Range.en_US
dc.subject.lcshPaleontology -- Wyoming -- Wind River Range.en_US
dc.titleHinge grades in the evolution of crassatellacean bivalves as revealed by Permian genera. American Museum novitates ; no. 2328en_US
dc.typetexten_US

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