A new family of calcareous microfossils from the Silurian of Gotland, Sweden

Scanning electron microscopy of polished, slightly etched rock surfaces of samples from the Silurian of Gotland. Sweden. revealed the presence of exce llently preserved calcareous microfaunas and microfloras. This paper illust rates several morphotypes of calcareous micro-organisms of unknown biologic al affinity, attributed to the new family Ovummuridae. Specimens of Ovummur us duoportius Minoura and Chitoku, a problematical microfossil. which was f irst described from the Upper Pennsylvanian of Kansas, USA, were found in a ddition to comparable microorganisms attributed to the following new taxa: Minourella gotlandica gen, et sp. nov.. Arouxina pluricellata gen, et sp. n ov. and Samtlebenella circumcamerata gen. et sp. nov. In addition. a few ot her problematical micro-organisms, probably belonging to the same family, a re described under open nomenclature. The enigmatic microfossils are compar ed with other known calcareous organisms. their possible biological affinit ies are discussed, and the different stages of diagenetic alteration and de struction are illustrated.