SANTA FE AND SAN MIGUEL COUNTIES
PECOS RIVER VALLEY LOCAITY
SANGGRE DE CRISTO FORMATION
EARLY PERMIAN
STEM: TETRAPODA GOODRICH, 1930
SUPERCLASS: AMNIOTA HAECKEL, 1866
CLASS: REPTILIA LAURENTI, 1768
SUBCLASS: SYNAPSIDA OSBORN, 1903
ORDER: PELYCOSAURIA COPE, 1878
SUBORDER: EUPELYCOSAURIA KEMP, 1982
INFRAORDER: OPHIACHODONTIA NOVA
Family: OPHIACODONTIDAE Nopsca, 1923
Ophiacodon sp
INFRAORDER: DIMETRODONTOMORPHA emend NOPCSA, 1925
Family: SPHENACODONTIDAE Marsh, 1878
Subfamily: SPHENACODONTINAE Marsh, 1878 (sensu Nopcsa, 1925)
Tribe: SPHENACODONTINI Marsh, 1878
Sphenacodon sp