OKTIGGEHA COUNTY
RIPLEY FORMATION
MIDDLE-UPPERMIDDLE MOSASAURUS ACME-ZONE
NAVESINKIAN AGE
EARLY MAASTRICHTIAN STAGE?
UPPER SENONIAN SUBEPOCH
GULF EPOCH
LATE CRETACEOUS
STEM: TETRAPODA GOODRICH, 1930
SUPERCLASS: AMNIOTA HAECKEL, 1866
CLASS: REPTILIA LAURENTI, 1768
SUBCLASS: DIAPSIDA OSBORN, 1904
SUPERLEGION: NEODIAPSIDA BENTON, 1985
LEGION: ARCHOSAUROMORPHA HUENE, 1946
SUPERCOHORT: CRUROTARSI SERENO & ARCUCCI, 1990
COHORT: CROCODYLOTARSI BENTON & CLARK, 1988
MAGNORDER: SUCHIA KREBS, 1974
SUPERORDER: CROCODYLOMORPHA WALKER, 1968
GRANDORDER: CROCODILIFORMES HAY, 1930
MICRORDER: MESOEUROCROCODYLIA WHETSTONE & WHYBROW, 1983
ORDER: EUSUCHIA emend HUXLEY, 1875
INFRAORDER: CROCODYLIA emend GMELIN, 1877
Family: GAVIALIDAE Cuvier, 1807
Subfamily: THORACOSAURINAE Cope, 1875 (sensu Nopcsa, 1928)
*Eothoracosaurus mississippiensis
= Thoracosaurus meirsanus (referred)