ARKANSAS

HEMPSTEAD COUNTY

MIDDLE FORK OF OZAN CREEK

OZAN FORMATION

MIDDLE CAMPANIAN STAGE

MIDDLE SENONIAN SUBEPOCH

UPPER GULF EPOCH

LATE CRETACEOUS

SUPERCLASS: AMNIOTA HAECKEL, 1866

CLASS: AVES LINNAEUS, 1758

AVEBREVICAUDA PAUL, 2001

SUBCLASS: ODONTORNITHES MARSH, 1873

INFRACLASS: ODONTOHOLCAE NOVA

MAGNORDER: HESPERORNITHES

ORDER: HESPERORNITHIFORMES FURBRINGER, 1888

Family: HESPERORNITHIDAE Marsh, 1872

Subfamily: HESPERORNITHINAE Nova

Hesperornis sp

ARKANSAS

HEMPSTEAD COUNTY

UPPER MARLBROOK MARL FORMATION

LATE CAMPANIAN STAGE

UPPERMOST SENONIAN SUBEPOCH

GULF EPOCH

LATE CRETACEOUS

STEM: TETRAPODA GOODRICH, 1930

SUPERCLASS: AMNIOTA HAECKEL, 1866

CLASS: REPTILIA LAURENTI, 1768

SUBCLASS: DIAPSIDA OSBORN, 1903

INFRACLASS: NEODIAPSIDA BENTON, 1985

LEGION: LEPIDOSAUROMORPHA BENTON, 1983

SUBLEGION: LEPIDOSAURIA HAECKEL, 1866 (DUMERIL & BIBRON, 1839)

MAGNORDER: SQUAMATA, OPPEL, 1811

SUPERORDER: LACERTILIA OWEN, 1842

GRANDORDER: SCINCOGEKKONOMORPHA SUKHANOV, 1961

MICRORDER: SCINCOMORPHA CAMP, 1923

ORDER: ANGUIMORPHA FURBRINGER, 1900

SUBORDER: DIPLOGLOSSA COPE, 1864

INFRAORDER: THECAGLOSSA COPE, 1890

PARVORDER: MONSTERSAURIA NORELL & GAO, 1977

Superfamily: VARANOIDEA Gray, 1827 (sensu Camp, 1923)

Family: MOSASAURIDAE Gervais, 1853

Infrafamily: NATANIA

Subfamily: Subfamily: PLATECARPINAE Williston, 1897

Tribe: PLIOPLATECARPINI Russell, 1967

Plioplatecarpus primaevus

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ARKANSAS

SUPERCLASS: AMNIOTA HAECKEL, 1866

CLASS: REPTILIA LAURENTI, 1768

SUBCLASS: DIAPSIDA OSBORN, 1904

INFRACLASS: EURYAPSIDA COLBERT, 1945

SUPERORDER: SAUROPTERYGIA OWEN, 1860

GRANDORDER: EOSAUROPTERYGIA emend RIEPPEL, 1994

ORDER: PLESIOSAURIA OWEN, 1840 NON BLAINVILLE, 1835

SUBORDER: PLESIOSAURIA OWEN, 1840 NON BLAINVILLE, 1835

INFRAORDER: PLIOSAUROMORPHA NOVA

Superfamily: PLIOSAUROIDEA Seeley, 1874

Family: PLIOSAURIDAE Seeley, 1874

Incertae sedis

Brimosaurus grandis
= Cimoliasaurus grandis
= Discosaurus grandis

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ARKSANSAS

HEMPSTEAD COUNTY

LAND ADMINISTERED BY THE ARKANSAS GAME AND FISH COMMISSION

MARLBROOK MARL

CAMPANIAN STAGE

GALLIC SUBEPOCH

GULF EPOCH

LATE CRETACEOUS

STEM: TETRAPODA GOODRICH, 1930

SUPERCLASS: AMNIOTA HAECKEL, 1866

CLASS: REPTILIA LAURENTI, 1768

SUBCLASS: DIAPSIDA OSBORN, 1904

INFRACLASS: EURYAPSIDA COLBERT, 1945

SUPERORDER: SAUROPTERYGIA OWEN 1860

PARVORDER: EOSAUROPTERYGIA emend RIEPPEL, 1994

ORDER: PLESIOSAURIA OWEN, 1840 NON BLAINVILLE, 1835

SUBORDER: PLESIOSAURIA OWEN, 1840 NON BLAINVILLE, 1835

INFRAORDER: PLESIOSAUROMORPHA NOVA

EUPLESIOSAURIA O’KEEFE, 2001

Superfamily: CRYPTOCLEIDOIDEA Williston, 1925

TRICLEDIA O’KEEFE , 2001

Family: POLYCOTYLIDAE Cope, 1869

Genus nova