Diversity dynamics of Early Cretaceous brachiopods in the tectonic units of Serbia: regional versus global patterns

Abstract

The Danubian, Getic, and Vardar tectonic units of Serbia (northern Neo-Tethys) provide a rich palaeontological record permitting quantitative assessment of the Early Cretaceous brachiopod diversity dynamics. The compilation and the subsequent revision of the available information permit to document the stratigraphical ranges of 44 species, 26 genera, 15 families, and 11 superfamilies. Three diversity peaks (Late Valanginian, Early Barremian, and Early Albian) are established, as well as the Late Barremian–Late Aptian long-term diversity decline. Brachiopods were absent in the Berriasian–Early Valanginian, Late Hauterivian, and the Middle–Late Albian. It is established that the post-Early Barremian diversity decline occurred chiefly because of rare taxa appearances. The vulnerability of representatives of the superfamilies Terebratuloidea and Hemithiridoidea to external influences shaped the regional diversity dynamics of brachiopods. The amplitude of changes of the assemblage composition through the epoch was high. There were both similarities and dissimilarities between the regional and global diversity dynamics of brachiopods, and weak correspondence between the patterns is an evidence of heterogeneity of the Early Cretaceous brachiopod diversity changes in the global space. For instance, the Barremian radiation did not occur on the planetary scale. The interplay of the global factors (global diversity dynamics, eustatic changes, and oceanic anoxic events) and the regional factors (e.g., changing depositional environment) is proposed to explain the observed diversity patterns.