Hyotissa semiplana is an extinct species of large saltwater oysters, a fossil marine bivalve mollusk in the family Gryphaeidae, the foam oystersUniversal Biological Indexer
Description Fossil shells of Hyotissa semiplana can reach a diameter of about .Kreidemuseum They have thick-walled valves, with rough, nodose surface.HALINA PUGACZEWSKA THE UPPER CRETACEOUS OSTREIDAE FROM THE MIDDLE VISTULA REGION (POLANDAnne Mehlin Sørensena, Finn Surlyka, John W.M. Jag Adaptive morphologies and guild structure in a high-diversity bivalve faunafrom an early Campanian rocky shore, Ivö Klack (Sweden)
Distribution Fossils of this species have been found in the Campanian-Maestrichtian of Poland, in the Santonian-Maestrichtian of Europe and North Africa and in the Campanian of South India.ANAND K. JAITLY and SANJAY K. MISHRA DISCOVERY OF THE OYSTER HYOTISSA SEMIPLANA (SOWERBY, 1813) FROM THE CAMPANIAN (LATE CRETACEOUS) OF SOUTH INDIA
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