Conodont biostratigraphy and biofacies across the Devonian-Carboniferous boundary in the Kule section (Uzbekistan).

New conodont data provide further constraints on the occurrence of the Devonian-Carboniferous boundary in the Kule section through the carbonate Novchomok Formation (Kitab Reserve, Uzbekistan). The stratigraphically condensed section includes the interval from the uppermost Famennian Pseudopolygnathus granulosus–lowermost Protognathodus kockeli zones to the middle Tournaisian Siphonodella crenulata Zone. In addition to revision of earlier published taxonomic and biostratigraphic data, two previously unreported taxa are described: Polygnathus sp. n. A and a peculiar form probably representing a new genus (gen. et sp. indet.). The biofacies analysis documents a succession of polygnathid, siphonodellid-polygnathid, polygnathid-siphonodellid to polygnathid-bispathodid, and again polygnathid-siphonodellid biofacies. The generic composition of the samples and relative abundance of Polygnathus purus reflect deep marine environments of the continental slope and rise.