Danuta Olszewska-Nejbert

Gypsum Microbialite Domes Shaped by Brine Currents from the Badenian Evaporites of Western Ukraine

Microbialite deposits are considered as a product of the interactions between activity of benthic microorganisms and physicochemical properties of environment. Activity of currents is one of the most important physical processes influencing the accretion of microbialite domes. The domes growing in current-swept areas usually show elongated shapes parallel to the dominating water flow direction.

New Cenomanian (Late Cretaceous) Hexactinellid Sponge Species from the Western Ukraine

Abstract The Cenomanian hexactinellid assemblages are relatively rare and are known only from England and France. The phosphatized sponges from the Pokuttian Podillia in western Ukraine seem to be taxonomically the most diverse Cenomanian hexactinellid assemblage known from Europe and the world. Several new hexactinellid taxa (Class Hexactinellida) are described from the Cenomanian of Pokuttian Podillia: Myliusia rakovensis n. sp., Verrucocoelia regularis n. sp., Tretochone cretacea n. sp., Heterochone boguckii, Dunikowskiella nezvyskensis n. gen. n. sp., and Moretiella foliacea n. sp. A new lychniscosidan genus Dunikowskiella is established within the family Callodictyonidae. Until now, genus Moretiella was reported only from the Aptian of Spain and the Albian of France. The extant genera Heterochone and Myliusia are also rare as fossils. Heterochone was known from the Campanian of Germany. Myliusia, noted in the Miocene of Spain, is well documented in Late Cretaceous for the first time. Tretochone was known only from recent times. The sponges studied lived in the shelf sea, shallower than most recent hexactinellids occur.