Vormsi lademe ostrakoodide morfoloogia fatsiaalsel gradiendil, Juhendaja: T. Meidla

Changes in the morphological features of ostracods in the Ordovician shelf basin have never been analysed, and there are no known features which could refer to their lifestyle and living environment. Based on previously published data on the distribution of ostracods in the Vormsi stage, the present work applies the unique Estonian collections to analyse changes in the morphology of ostracode carapaces along the facies gradient. For the first time, changes in the roundness, shape, convexity, and spinosity of the ostracode carapace, paleocope dimporhism and morphology of the main sulcus of paleocopes are analysed quantitatively along facies gradient. In addition, changes in the sculpture and ornamentation of the valve surface along the facies gradient are analysed and taxonomic distribution of ostracods, based on the number of individuals, is published. Several clear trends in the taxonomic distribution are revealed and changes in morphological characteristics along the facies gradient described, some of them being unconsistent with previous knowledge.