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Abstract
A new fossil diatom with a well-developed raphe-bearing keel and continuous junction line in the strongly bilobate wings is described as Entomoneis calixasini Paillès, Blanc-Valleron & Poulin sp. nov. This species was found at numerous levels within a 4.6-m-long core recovered from the north-western slope of the Central High of the Marmara Sea, Turkey. Detailed light and scanning electron microscopy were used to characterize this species. Entomoneis calixasini is unique by a wing resembling interconnecting dunces’ caps. This species, sometimes the most abundant, is present between 44 and 395 cm of MET09-GR02 core sediments, corresponding to the Pleistocene last glacial period (brackish lacustrine sediments). It was not observed in the marine sediments above, or in other core sediments from the Marmara Sea or elsewhere in Pleistocene or Holocene sequences. It is absent in modern collections and from the literature, and is considered extinct.
Acknowledgements
We are indebted to the captain and crew members of the 2009 MARMESONET cruise on board the RV Suroît who allowed the collection of GR02 core. We also thank Céline Grall and Jérôme Demange for their contribution in core description and sampling. Financial support for this work was provided by MNHN (ATM Microorganismes) and by ECCOREV to the French team, and the Canadian Museum of Nature to M. Poulin. We are very grateful to K. Osada, D. Harwood, E. Fourtanier, S. Servant, S. Pestrea, J. Dejax, E. Masure, D. Pons and all the colleagues who gave advice on this new species. Thanks to A.-M. Brunet for sample preparation, A. Lethiers for help in the photographic plates and A. Cambreleng for art work. The authors thank C. Riaux–Gobin and an anonymous reviewer for their helpful critical comments and suggestions. First presented as a poster at the 7th Central European Diatom meeting in Thonon-les-Bains, France, 18–20 September 2013.