Evidence for Palaeozoic orthoconic cephalopods with bimineralic shells |
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Authors: | Kenneth De Baets Axel Munnecke |
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Affiliation: | GeoZentrum Nordbayern, Friedrich‐Alexander Universit?t Erlangen‐Nürnberg, Loewenichstrasse 28, D‐91054 Erlangen, Germany |
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Abstract: | Based on the aragonite composition of extant and exceptionally preserved fossil cephalopods going back to the early Palaeozoic, it is commonly assumed that all externally shelled cephalopods had an aragonitic shell wall. We demonstrate herein that at least two taxa of Siluro‐Devonian orthoconic nautiloids (Dawsonoceras, Spyroceras) had an original bimineralic shell, which developed convergently with gastropods and bivalves. |
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Keywords: | biomineralization calcite– aragonite Orthoceratida bimineralic shell biogenic carbonate convergent evolution |
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