Silurian and Lower Dewonian anaspids (Agnatha) from Severnaya Zemlya (Russia)

In the Severnaya Zemlya Archipelago, Silurian anaspids are represented by scales of at least six different types of sculpture, and some subtypes, called Birkeniida sp. C, Birkeniida sp. C1, Birkeniida sp. C?, Birkeniida sp. D, Birkeniida sp. F, Birkeniida sp. F?, Birkeniida sp. G., Birkeniida sp. H and Birkeniida sp. J. In addition, Birkenia? sp. was recognized. A new taxon was erected on the basis of the material from the Severnaya Zemlya Formation, Lower Devonian. In the specimen, the trunk squamation is rather well preserved, but the head and the caudal fin are lacking. Characteristic are very big dorsal ridge scales. The stratigraphical range of anaspids on Severnaya Zemlya is from Wenlock to Lochkov.