Fort Crittenden Formation - AbsoluteAstronomy.com

The Fort Crittenden Formation is a geological formation in Arizona whose strata date back to the Late Cretaceous

Late Cretaceous

The Late Cretaceous is the younger of two epochs into which the Cretaceous period is divided in the geologic timescale. Rock strata from this epoch form the Upper Cretaceous series...

. Dinosaur remains are among the fossils that have been recovered from the formation.

Amphibians

Amphibian Amphibian Amphibians , are a class of vertebrate animals including animals such as toads, frogs, caecilians, and salamanders. They are characterized as non-amniote ectothermic tetrapods... s of the Fort Crittenden Formation
Genus	Species	Location	Stratigraphic position	Abundance	Notes
Opisthotriton Opisthotriton Opisthotriton is an extinct genus of prehistoric salamanders that lived in North America between at least the Upper Cretaceous and the Paleocene....	Indeterminate
Scapherpeton Scapherpeton Scapherpeton is an extinct genus of prehistoric amphibian.-See also:* Prehistoric amphibian* List of prehistoric amphibians...	Indeterminate

Archosaurs

Archosaur Archosaur Archosaurs are a group of diapsid amniotes whose living representatives consist of modern birds and crocodilians. This group also includes all extinct non-avian dinosaurs, many extinct crocodilian relatives, and pterosaurs. Archosauria, the archosaur clade, is a crown group that includes the most... s of the Fort Crittenden Formation
Genus	Species	Location	Stratigraphic position	Abundance	Notes	Images
Allognathosuchus Allognathosuchus Allognathosuchus is an extinct genus of alligatorine crocodylian with a complicated taxonomic history. This small alligatorine is known for its stout jaws and bulbous teeth, found near the rear of the tooth row in upper and lower jaws. These adaptations have historically been interpreted as...	Indeterminate			Known only from a single scute.	Paleontologists Robert M. Sullivan and Spencer G. Lucas question the presence of Allognathosuchus in the formation because the referred remains were so scant and Allognathosuchus has never been reported in Cretaceous strata previously. They regard the referred scute as belonging to an indeterminate alligatoroid.
Alamosaurus Alamosaurus Alamosaurus is a genus of titanosaurian sauropod dinosaur from the Late Cretaceous Period of what is now North America. It was a large quadrupedal herbivore. Isolated vertebrae and limb bones indicate that it reached sizes comparable to Argentinosaurus and Puertasaurus, which would make it the...	Indeterminate
Gorgosaurus Gorgosaurus Gorgosaurus is a genus of tyrannosaurid theropod dinosaur that lived in western North America during the Late Cretaceous Period, between about 76.5 and 75 million years ago. Fossil remains have been found in the Canadian province of Alberta and possibly the U.S. state of Montana....
Richardoestesia	Indeterminate
Saurornitholestes Saurornitholestes Saurornitholestes is a genus of carnivorous dromaeosaurid theropod dinosaur from the late Cretaceous of Alberta, Montana and New Mexico....	Indeterminate

Bony fishes

Bony fishes of the Fort Crittenden Formation
Genus	Species	Location	Stratigraphic position	Abundance	Notes	Images
Melvius	Indeterminate
Pachyrhizodus Pachyrhizodus Pachyrhizodus is an extinct genus of bony fish.-Further reading:*Wildlife of Gondwana: Dinosaurs and Other Vertebrates from the Ancient Supercontinent by Pat Vickers Rich, Thomas Hewitt Rich, Francesco Coffa, and Steven Morton...	Indeterminate

Cartilaginous fishes

Cartilaginous fishes of the Fort Crittenden Formation
Genus	Species	Location	Stratigraphic position	Abundance	Notes
Myledaphus	M. bipartitus

Turtles

Turtle Turtle Turtles are reptiles of the order Testudines , characterised by a special bony or cartilaginous shell developed from their ribs that acts as a shield... s of the Fort Crittenden Formation
Genus	Species	Location	Stratigraphic position	Abundance	Notes
Adocus
Aspideretes Aspideretes Aspideretes is a genus of soft-shelled turtles . It has been found to be so closely related to the Burmese Peacock Softshell that it is probably better united with this species under Nilssonia, the older name...
Basilemys
Plastomenus

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