What is "dvinosaurus"

Dvinosaurus is a genus of extinct temnospondyl amphibian from the Late Permian of Russia. The first three species, D. primus (the type species), D. secundus, and D. tertius, were described by Russian paleontologist Vladimir Prokhorovich Amalitskii in 1921. Dvinosaurus was first found near the village of Sokolki in Arkhangelsk and named after the Northern Dvina River, which was close to the locality where it was discovered. The holotype is cataloged as PIN2005/35, and consists of only a skull. Amalitskii's D. tertius is now considered synonymous with D. secundus. Two additional species, D. egregius, and D. purlensis, were named by Mikhail Shishkin in 1968. These were named from a fossilized skull and a partial lower jaw, respectively.