NIZHNII NOVGOROD PROVINCE
SHAKHUN’YA DISTRICT
TOPMOST VYATSKIAN GORIZONT
LATE PERMIAN
STEM: TETRAPODA GOODRICH, 1930
SUPERCLASS: AMNIOTA HAECKEL, 1866
CLASS: REPTILIA LAURENTI, 1768
SUBCLASS: SYNAPSIDA OSBORN, 1903
SUPERORDER: THERASPIDA BROOM, 1905
GRANDORDER: EUTHERAPSIDA
MICRORDER: NEOTHERAPSIDA
ORDER: THERIODONTIA OWEN, 1881
EUTHERIODONTIA
SUBORDER: THEROCEPHALIA BROOM, 1903
Family: PRISTEROGNATHIDAE Broom, 1906
*Hexacynodon purlinensis
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