Abstract
As a result of examination of the collection of holdfasts of stemmed echinoderms from the Ordovician of the Leningrad oblast, Russia, all holdfasts are divided into two large groups: “unbranched” and “branched.” Three morphotypes of branched holdfasts are identified and described in detail. Morphogenetic transitions between morphotypes and their relationship with the peculiarities of the evolution of stemmed echinoderms in the Ordovician evolutionary radiation were identified.
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ACKNOWLEDGMENTS
We are grateful to V.B. Kushlina and G.V. Mirantsev (Laboratory of Higher Invertebrates, Paleontological Institute, Russian Academy of Sciences), S.S. Terentiev and N.K. Semenov (St. Petersburg), as well as A.A. Krutykh (Department of Paleontology, Geological Faculty, Moscow State University) for help in collecting and processing the material. Thanks are also due to G.V. Mirantsev for his comments and feedback on this article.
Funding
This study was partially supported by the Russian Science Foundation (project no. 19-14-00346 (for S.V. Rozhnov) and the Russian Foundation for Basic Research (project no. 18-04-01046A (for G.A. Anekeeva)). This article is a contribution to the International Geoscience Program (IGCP) Project 653—The Onset of the Great Ordovician Biodiversification Event.
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Translated by M. Batrukova
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Anekeeva, G.A., Rozhnov, S.V. Branched Holdfasts of Stemmed Echinoderms from the Middle Ordovician of the Leningrad Region. Paleontol. J. 55, 1100–1108 (2021). https://doi.org/10.1134/S0031030121100026
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DOI: https://doi.org/10.1134/S0031030121100026