Acanthodians from the Silurian–Devonian boundary beds of Novaya Zemlya Archipelago, Russia

Abstract

An acanthodian assemblage is reported for the first time from the Silurian-Devonian boundary beds of Novaya Zemlya Archipelago, Russia. The acanthodian scales and rare other vertebrate microremains were in a sample collected from the Reliktovoe Formation of the western coast of Inostantzev Bay, North Island. The assemblage includes Gomphonchus mediocostatus, Gomphonchoporus hoppei taxa previously described from the Pridoli-Lochkovian of Laurussia, and Taimyrolepis composita occurred in the Lochkovian of Siberia. Gomphonchus mediocostatus and Gomphonchoporus hoppei are widely distributed in the Baltica palaeogeographic province, and Taimyrolepis is known from the Siberia province, indicating connection between those provinces.

Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U.S.A.

“…Comparison-The type scales of Gomphonchus mediocostatus are from an upper Přidolí East Balticderived erratic limestone; the species is also recorded from Lithuania, Timan-Pechora (Valiukevičius 2005), Latvia (Valiukevičius 2004b), the Welsh Borderlands (Vergoossen 1999a) and Novaya Zemlya (Burrow et al 2018). In Latvia, Valiukevičius (2004b) Remarks-All identifiable scales of the Nostolepistype sensu lato (e.g., Gross 1947Gross , 1971) recovered from the BC II section, except those assigned to Nostolepis matukhini, correspond to species that have been reassigned to Nostovicina Valiukevičius and Burrow (2005), which all lack Stranggewebe (short parallel-oriented mesodentine tubules) in the crown.…”