Revision of the Devonian fenestrate bryozoan genera Cyclopelta Bornemann, 1884 and Pseudoisotrypa Prantl, 1932, with description of a rare fenestrate growth habit.

Abstract

The fenestrate bryozoan genus Cyclopelta is common and locally abundant in Devonian rocks of central and western Europe. Cyclopelta is a junior homonym and is here renamed Bigeyina. The Bohemian genus Pseudoisotrypa, very closely related with Bigeyina and formerly interpreted as a junior synonym of the latter, is restored herein as a valid taxon. Revised diagnoses of both genera and their type species are provided. Also, an extremely rare variation on the conical growth habit is reported in Bigeyina and implies higher plasticity in this genus than usual in fenestrates. The presence of abundant Bigeyina zoaria with this rare growth habit in the well known outcrop of Arnao (Spain), emphasizes the need for the preservation of its paleontological heritage.