Late Early Permian plant fossils from the Canadian High Arctic: a rare paleoenvironmental/climatic window in northwest Pangea

Recently discovered megafossil plant remains in late Early Permian (Kungurian) marine sediments on northern Axel Heiberg Island, Canadian Arctic Archipelago, provide a much needed datum point for paleobiogeographic considerations in this part of North America. The fossil plants represent at least ten families belonging to several major groups (sphenopsids, ferns, pteridosperms, ginkgos, cordaitaleans, and conifers). The conifers Rufloria and Walchia are the most commonly represented taxa, while other gymnosperms constitute much of the remaining collection. Lycopsids are absent and sphenopsids as well as ferns are present, but rare. The plant material probably originated from Crockerland and has a complex taphonomic history. There appears to be a strong phytogeographic connection with the Angaran floral realm. In addition, some floral elements occurring here are known mostly from the Early Mesozoic elsewhere. These findings support the idea that plant evolution was most intensive in extrabasinal settings; with migration into the depositional lowlands often occurring at times when climatic conditions became favorable for range expansion out of the uplands. The Axel Heiberg Island flora is another datum point for rare, but significant late Early Permian age floras on the North American continent.