New organic-walled dinoflagellate cysts from recent sediments of Central Asian seas

Recent to sub-recent sediments from the Caspian Sea, the Kara-Bogaz-Gol Bay, the Enseli lake and the Aral Sea contain the new organic-walled dinoflagellate cysts Caspidinium, Caspidinium rugosum and Impagidinium caspienense. C. rugosum has S-type paratabulation, dextral torsion and low relief intratabular ornamentation. L caspienense has low intratabular suturo-cavate relief, parasutural septa irregular in height and a high septum at the junction of paraplate I and the sulcus. The accompanying species consist of Spiniferites cruciformis, Lingulodinium machaerophorum, Pyxidinopsis psilata, cysts of Pentapharsodinium dalei and Brigantedinium spp. S. cruciformis varies from specimens with a cruciform body with a well-developed postero-lateral membranous flange to specimens with a pear-shaped body, reduced processes and no flange. Sea-surface data from these Central Asian seas suggests that the two new taxa C rugosum and I caspienense are probably related to low salinity conditions (12-13). (C) 2004 Elsevier B.V All rights reserved.