Morphological relationships of Ancyrospora species from the Givetian and Frasnian deposits of the Pan-Arctic region

Miospores with spines that have bifurcate tips and an equatorial flange from the genus Ancyrospora were an important part of the Mid and Late Devonian spore flora. A number of the early species were described from the Arctic regions of both Canada (Nunavut) and the Timan, Russia. The history of the genus Ancyrospora is reviewed, rediagnosed and compared with Hystricosporites and Nikitinsporites two genera that also possess bifurcate tipped spines. Material from Arctic Canada and Russia was investigated to compare the Givetian and Frasnian species of Ancyrospora that were described in early publications by McGregor, Owens, and Naumova. The species Ancyrospora ampulla, A. melvillensis, A. simplex, A. incisa, A. arguta, A. laciniosa and A. polyacantha are illustrated and described using the same terminology including profiles of the bifurcate sculptural elements. Morphological lineages are recognised between the different species and the Ancyrospora melvillensis morphon defined. Comparative range charts are presented from both Arctic Canada and Russia. Many of the taxonomic issues in comparing Canadian and Russian Ancyrospora are resolved.