Devonian Vertebrate Assemblages from the Tsilma River Section (Middle Timan)

This paper presents new data on the taxonomic composition of the vertebrate assemblages from the Middle and Upper Devonian of the Tsilma River section (northern part of the Middle Timan), as well as their stratigraphic and areal distribution. The coeval vertebrate assemblages of both the Timanian and Ust’yaregian Regional Stages cropping out in the upper and middle reaches of the Tsilma River area differ substantially in diversity and composition. This is apparently due to the contrasting facies of these deposits: in the upper reaches of the Tsilma River they were formed in lacustrine/wetland environments, whereas in the middle reaches of the Tsilma River, deposition occurred in a predominantly shallow marine basin. Comparison of the vertebrate assemblages from the studied sections with other regions confirms their affinity to the Baltic paleozoogeographical province. The new results considerably complement the data on the Devonian vertebrate assemblages of the Middle Timan and allow correlation with local stratigraphic units in adjacent areas to be amended.