Distribution, migration routes, refugia and centers of origin of Rugosa (Anthozoa) during the late Viséan-Bashkirian and the Serpukhovian–Bashkirian (Carboniferous) mass extinction

Abstract

Two rugose coral superprovinces connected through the Rheic Ocean occurred during the Mississippian-Lower Pennsylvanian: the Palaeotethyan and the North American. They perhaps continued up to the Moscovian, that is until the collision of Gondwana and Laurussia and the appearance of Pangea gave rise to two realms, the Palaeotethyan and the Cordillera–Arctic Uralian. Restricted communication between the superprovinces in the Tournaisian and up to the middle Viséan inclusively resulted in the partial isolation of the North American superprovince from the mainstream of evolution of the rugose corals—i.e., the Palaeotethyan superprovince. Global warming in the late Viséan and the early Serpukhovian led to the opening of the circum-Laurussia continent circulation and allowed eastward migrations of some North American genera to the Palaeotethyan superprovince, though several genera remained endemic. As a result of the patchy distribution of the Serpukhovian and Bashkirian Rugosa, the large Palaeotethyan superprovince was distinctly differentiated in faunal content within domains by, and their response to, the end of the Mississippian faunal turnover. Refugia (such as North African basins), endemic centers of origin (like Akiyoshi Terrane), expanded centers of origin (like the Donets Basin), and domains with mixed roles (such as South China, Ural–Timan–Novaya Zemlya, and western North America) occurred during the late Serpukhovian–early Bashkirian. This differentiation resulted in the local extension of the Mississippian–Pennsylvanian rugose coral turnover to the Homoceras–Hudsonoceras Geozone, mostly towards the end of the Serpukhovian. That important event is best documented so far in the Donets Basin (Ukraine).