New fusulinid data from the Kolosseum locality, central Spitsbergen, show the process of fusulinid evolution in transitional Middle to Upper Carboniferous beds of the Arctic region. This well-preserved fusulinid fauna provides a clear understanding of the nature of Moscovian-Kasimovian fusulinid evolution; particularly in the Arctic region. Fusulinid assemblages in the Moscovian/Kasimovian boundary beds in Spitsbergen show a predominance of representatives of the Protriticites-Montiparus-Rauserites lineage. Representatives of the Praeobsoletes-Obsoletes-Triticites lineage in Spitsbergen are very rare and occur later than in the stratotype region, the Russian Platform. Four fusulinid zones similar to zones in the stratotype area are defined upwards: Fusulinella bocki Zone, Protriticites ex. gr. ovatus-Quasifusulinoides quasifusulinoides Zone, Protriticites pseudomontiparus-Obsoletes obsoletus Zone and Montiparus montiparus Zone, respectively. Precise correlation of the Moscovian/Kasimovian transition of Spitsbergen to adjacent areas (Northeast Greenland and Canadian Arctic) as well as with the Moscovian-Kasimovian of the region of the Moscow basin, Spain, and Garnie Alps is suggested. The Moscovian/Kasimovian boundary of Eurasia is approximately correlative with the Middle Desmoinesian (base of DS-3 fusulinid zone of Wilde 1990) of North America. Data from Spitsbergen are of great importance for resolving the problem of Middle/Upper Carboniferous boundary recognition regarding fusulinid phylogenies. Copyright: Paleontological Society.
