Callovian (Middle Jurassic) cyclostome bryozoans from the Zalas Quarry, southern Poland

Abstract

The specimen-rich and diverse bryozoan fauna from the Callovian hardground at Zalas Quarry in southern Poland is described. Twenty-two taxa of cyclostomes are recorded, of which three species are proposed as new: Microeciella calloviana, Reptomultisparsa viskovae and Mesonopora walteri. Due to preservational problems and an insufficient number of fertile colonies, species-level determination of fourteen forms was not possible. The most common bryozoans present are sheet-like bereniciform colonies, with uniserial runners and oligoserial ribbons less abundant. The number of the Callovian taxa present in the Zalas Quarry is very similar to the Upper Bathonian-Lower Callovian bryozoan assemblage from the classic locality of Balin in southern Poland. Taking the strictly Callovian age into account, the Zalas assemblage is the most diverse for that age ever noted.