Bryozoan Diversity Dynamics at the Devonian–Carboniferous Transition: Evidence from Transcaucasia

The Devonian–Carboniferous transition was marked by a series of perturbations in the geological and biological evolution. palaeontological data from Transcaucasia allowed bryozoan diversity dynamics on northern Gondwanan margin (southern periphery Palaeo-Tethys Ocean) to be documented at this transition. Taxonomic ranges 43 species, 26 genera, 19 families, 4 orders were analysed reveal changes total diversity, number appearances, disappearances, turnover rates per substages. It is established that rather high beginning end Famennian, as well Late Tournaisian. declined significantly Middle–Late Famennian Early Tournaisian due combination disappearances low appearances. turnovers remained strong, they peaked mid-Famennian. These regionally match patterns recorded globally Southern Siberia. Hypothetically, crises related global events (anoxia mass extinctions), which weakened bryozoans’ resistivity negative external influences.