Article: Biogeography of Carboniferous ectoproct bryozoa
Cryptostomes, principally of the suborders Fenestelloidea and Rhabdomesina. dominated Carboniferous ectoproct bryozoan assemblages. Cystoporates and trepostomes were generally less diverse and less numerous. The bryozoan faunas occurred in eleven geographic regions during the Tournaisian, Visean, Namurian A. Namurian B and C, Westphalian. and Stephanian. Early Carboniferous bryozoans rapidly evolved from Devonian stocks. Visean generic assemblages are highly diverse, abundant, and widespread. In contrast, Namurian B and C generic assemblages have low diversity, are sparse, and greatly restricted. Diversification began again in the Westphalian, continued in the Stephanian. and led to the Early Permian ectoproct lineages. Differentiation of assemblages into northern, central, and southern Tethyan faunal regions took place in the late Westphalian. At different times during the Carboniferous, dispersal and exchange of bryozoan genera occurred between faunal regions. Some genera disappeared Torn one region and appeared in olhers. suggesting latitudinal shifts in environmental conditions possibly due to climatic changes.