UTAH AND ARIZONA
MITCHELL BUTTE
MONUMENT VALLEY
SE OF MONUMENT PASS
ORGAN ROCK
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 ferocior
_____________________________________________________________________________________
UTAH AND ARIZONA
MONUMENT VALLEY
EAST OF MITCHELL BUTTE
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
_____________________________________________________________________________________
UTAH AND ARIZONA
MONUMENT VALLEY
ORGAN ROCK
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: DIMETRODONTOMORPHA emend NOPCSA, 1925
Family: SPHENACODONTIDAE Marsh, 1878
Subfamily: SPHENACODONTINAE Marsh, 1878 (sensu Nopcsa, 1925)
Tribe: DIMETERODONTINI Nopcsa, 1925
Ctenospondylus casei
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