Mesenosaurus romeri -Efremov, 1938- skeleton
Synapsida: Pelycosauria: Varanopseidae
Locality: Mezen River, Arkhangelsk Region, northern European Russia
Age: Late Permian, 260 million years ago
Meaning of name: "reptile from Mezen"
Similarly abundant was the small insectivorous pelycosaur Mesenosaurus of the family Varanopseidae, whereas
the remains of the herbivorous pelycosaur Ennatosaurus of the family Caseidae are comparatively more rare.
This small insectivorous reptile was an eosuchian, the group that gave rise to the archosaurs and lizards,
the core members of the sauropsid assemblage which was to replace the therapsid assemblage in the Triassic.
Mesenosaurus was found in red clays deposited in an ancient lake in what is now northern Russia.
Both these pelycosaur families were widely distributed in the Early Permian of North America,
while in the Late Permian of East Europe they were a relict component of the land assemblages.