Plain-Language Summary:
Fusulinids are large benthic foraminifera (single-celled organisms related to amoebae) that secrete a characteristic grain-shaped shell. They are very common in Upper Paleozoic sediments and comprise one of the primary index fossil groups. This report concerns the stratigraphic distribution and evolutionary history of two main Upper Paleozoic fusulinid lineages from middle-upper Carboniferous sediments exposed on the island of Spitsbergen, Norway. Within the Spitsbergen stratigraphical succession four distinct fusulinid zones similar to those in the Russian Platform stratotype sections can be recognized. These zones are defined and the morphologies of the species used in those zone definitions illustrated. In particular the authors suggest that their zones can be used to more accurately place the boundary between middle and upper Carboniferous time (the Moscovian - Kasimovian boundary) in remote stratigraphical successions.
A discussion of the stratigraphical distribution of several key fusulinid genera and species belonging to different lineages follows with particular attention being paid to the type Moscovian - Kasimovian section in the Moscow Basin and time-equivalent sediments in Spain, the Carnic Alps, northeast Greenland, the Canadian Arctic, and North America. These data suggest that (1) a complete record of fusulinid succession occurs in the Spitsbergen locality, (2) the stratigraphic first appearance of the Protriticites-Montiparus-Rauserites fusulinid lineage take place well before the first appearance of the Praeobsoletes-Obsoletes-Triticites lineage, and (3) the Spitsbergen faunas can be used to correlate between the Moscovian - Kasimovian boundary beds in the Moscow basin type area and Canadian Arctic and North American successions.