''Procaimanoidea'' ("Before
Caiman
A caiman (also cayman as a variant spelling) is an alligatorid belonging to the subfamily Caimaninae, one of two primary lineages within the Alligatoridae family, the other being alligators. Caimans inhabit Mexico, Central and South Ameri ...
-forms") is an
extinct genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...
of
alligatorid
The family Alligatoridae of crocodylians includes alligators, caimans and their extinct relatives.
Phylogeny
The superfamily Alligatoroidea includes all crocodilians (fossil and extant) that are more closely related to the American alligator t ...
from the
Eocene
The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', " ...
of
North America. It was named posthumously in 1946 by
Charles W. Gilmore; the
type species
In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen( ...
is ''P. utahensis'', from the
Uintan
The Uintan North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages
The North American land mammal ages (NALMA) establishes a geologic timescale for North American fauna b ...
(middle Eocene) of
Utah
Utah ( , ) is a state in the Mountain West subregion of the Western United States. Utah is a landlocked U.S. state bordered to its east by Colorado, to its northeast by Wyoming, to its north by Idaho, to its south by Arizona, and to its ...
. It is based on
USNM 15996, a nearly complete skull and partial left hind leg.
A second species, ''P. kayi'', was named in 1941 by C.C. Mook as a species of ''
Hassiacosuchus'', for remains from the
Bridgerian
The Bridgerian North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), typically set from 50,300,000 to 46,200,000 years BP lasting .
It is usually c ...
(early Eocene) of
Wyoming
Wyoming () is a state in the Mountain West subregion of the Western United States. It is bordered by Montana to the north and northwest, South Dakota and Nebraska to the east, Idaho to the west, Utah to the southwest, and Colorado to the sou ...
.
It was reassigned to ''Procaimanoidea'' in 1967 by Wassersug and Hecht.
Description
''Procaimanoidea'' was a small alligatorid, and slightly
heterodont
In anatomy, a heterodont (from Ancient Greek, Greek, meaning 'different teeth') is an animal which possesses more than a single tooth morphology (biology), morphology.
In vertebrates, heterodont pertains to animals where teeth are differentiate ...
, the last four teeth on each side of the jaws having blunt tips.
[
]
Phylogeny
Recent studies have consistently resolved ''Procaimanoidea'' as a member of Alligatorinae
Alligatorinae is a subfamily within the family Alligatoridae that contains the alligators and their closest extinct relatives, and is the sister taxon to Caimaninae (the caimans). Many genera in Alligatorinae are described, but only the genus ' ...
, although its relative placement is disputed, as shown by the cladogram
A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to ...
s below.
References
External links
''Procaimanoidea''
in the Paleobiology Database
The Paleobiology Database is an online resource for information on the distribution and classification of fossil animals, plants, and microorganisms.
History
The Paleobiology Database (PBDB) originated in the NCEAS-funded Phanerozoic Marine Paleo ...
Alligatoridae
Eocene crocodylomorphs
Eocene reptiles of North America
Prehistoric pseudosuchian genera
Taxa named by Charles W. Gilmore
{{paleo-archosaur-stub