Acta Palaeontologica Polonica

Emergence and extinction of the Givetian to Frasnian bryozoan faunas in the Kostomłoty facies zone, Holy Cross Mountains, Poland

Iraida P. Morozova, Olga B.Weis, and Grzegorz Racki

Acta Palaeontologica Polonica 47 (2), 2002: 307-317

Devonian bryozoans have been investigated from two Givetian to Frasnian localities in the Holy Cross Mts (Central Poland), representing fossiliferous ramp slope facies of the Kostomłoty facies zone (north-western periphery of the Kielce carbonate platform). Thirteen genera belonging to four families and three orders have been identified. Bryozoans show close relation to previously described Givetian and Frasnian bryozoan faunas of France, but also some affinities to easterly regions (e.g., Kuzbass). The main immigration episodes are related to late Givetian and middle Frasnian deepening pulses. The replacement of locally rich and diverse Givetian carbonate bank faunas by overall impoverished Frasnian reef-complex associations largely corresponds to a major extinction event in the evolutionary history of Bryozoa. Five new species are described by I. Morozova and O. Weis: Eridotrypella arguta, Eridotrypella exserta, Eostenopora nimia, Primorella nitida, Primorella indigena.

Key words: Bryozoa, Devonian, Givetian, Frasnian, taxonomy, biogeography, Poland.

Iraida P. Morozova, Olga B.Weis [], Paleontological Institute, Russian Academy of Sciences, Profsoyuznaya Str. 123, 117647 Moscow, Russia; Grzegorz Racki [], Wydział Nauk o Ziemi, Uniwersytet Śląski, ul. Będzińska 60, PL−41−200 Sosnowiec, Poland.

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