NAJNOVIJI OBJAVLJENI RADOVI
Revision of the endemic dinoflagellate cyst genus Pontiadinium Stover & Evitt, 1978 from Lake Pannon and the Paratethys realm (Late Miocene–Early Pliocene, Central Europe)
The biota of the brackish-water Lake Pannon in the Pannonian Basin is characterized by remarkable endemism due to the isolated evolution of the lake for 8 myr after the last Miocene marine connection ceased ca. 11.6 million years ago. The dinoflagellate cyst assemblages of Lake Pannon are without any modern analogue; they have the closest affinity to the Pliocene-Holocene associations of the Ponto-Caspian realm. A conspicuous feature of their endemism is the large, probably ecophenotypic variation in the morphology of these brackish-water dinoflagellate cysts that challenges taxonomy and complicates biostratigraphical and ecological interpretations. We revised and emended the generic description and all its species of the biostratigraphically important marker taxon, Pontiadinium. A new species is described as Pontiadinium szentaiae sp. nov. from Našice (northern Croatia) that is characterized by unique trabeculate sutural septa, a previously unknown morphological features. The origin of these dinoflagellate cyst morphologies have been widely discussed in the past and usually attributed as simple ecophenotypic variants of other cyst genera (e.g. Imapgidinium?) as a response to the subnormal marine salinity in Lake Pannon. We concluded that although the morphological variants could have emerged first as simple ecophenotypes or features providing adaptive advances (e.g. anti-predation or facilitating buoyancy in episodically stratified marginal seas and lakes), the long-term isolation of the lake led to the evolutionary development of new dinoflagellate cyst species and genera.This work was done in collaboration with the Geological Survey of Canada, MOL Hungarian Oil and Gas Plc., MTA-MTM-ELTE Research Group for Palaeontology of the Hungarian Academy of Sciences, and the Eötvös Loránd University (Hungary).
The article is available at the following link: https://onlinelibrary.wiley.com/doi/10.1002/gj.3664 .
