Biometric revision of the genus Stenophragmidium Bassler, 1952 (Trepostomata, Bryozoa) from the Upper Palaeozoic

Abstract

This study comprises a complete systematic revision of the trepostome genus Stenophragmidium Bassler, 1952 (Trepostomata, Bryozoa) from the Upper Palaeozoic, that incorporates stratigraphical, palaeogeographical, palaeoecological, palaeobiological, statistical and ultrastructure studies. Stenophragmidium exhibits erect ramose, hollow erect, adnate sheet and encrusting colony forms. Similar to Tabulipora, it differs in the possession of hemiphragms, consistently present features that distinguishes it from all other trepostomes. Hemiphragms are processes that extend from the proximal wall of the autozooecial chamber. Hitherto the status of Stenophragmidium and some species within it has been unclear, so therefore a complete taxonomic revision of the genus has been undertaken. An integral part of the taxonomic revision was the application of univariate, bivariate and particularly multivariate statistics which allowed for objective recognition of species. Additionally the statistical methodology described in this thesis is offered as a model for application in many types of similar palaeontological studies.