A diverse crinoid fauna from the Middle Jurassic (Upper Bajocian-Callovian) of the Polish Jura Chain and Holy Cross mountains (south-central Poland)

A systematic account of a diverse crinoid fauna from the Middle Jurassic (Upper Bajocian-Callovian) of the Polish Jura Chain and Holy Cross Mountains (south-central Poland) is presented. The description is supplemented with a list of all crinoid species found hitherto in the Tatra Mountains and the Pieniny Klippen Belt (Poland), which were a part of the northern margin of the Tethys during Middle Jurassic time. Balanocrinus hessi seems to be endemic and established its own population in the epicontinental sea. Other stalked crinoids entered from the Tethys through the East-Carpathian Gate or from a westerly way, and constitute a typical Mediterranean fauna. Stemless forms are regarded to be unsuccessful immigrants. The crinoid remains are preserved mostly as columnals and pluricolumnals, the majority of which are encrusted and bored by various epi- and endobionts. No encrustation or boring, however, occurred during the lifetime of these crinoids. The association of well-preserved columnals/pluricolumnals with the broken and abraded isolated columnals, may be the evidence of a within-habitat time-averaging of the crinoid assemblages.