''Diplosaurus'' is an extinct

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

goniopholidid Goniopholididae is an extinct family of moderate-sized semi-aquatic neosuchian crocodyliformes. Their bodyplan and morphology are convergent on living crocodilians. They lived across Laurasia (Asia, Europe and North America) between the Middle Ju ...

mesoeucrocodylia Mesoeucrocodylia is the clade that includes Eusuchia and crocodyliforms formerly placed in the paraphyletic group Mesosuchia. The group appeared during the Early Jurassic, and continues to the present day. Diagnosis It was long known that M ...

Fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

s have been found from the

Western United States The Western United States (also called the American West, the Far West, and the West) is the region comprising the westernmost states of the United States. As American settlement in the U.S. expanded westward, the meaning of the term ''the Wes ...

and range from

Late Jurassic The Late Jurassic is the third epoch of the Jurassic Period, and it spans the geologic time from 163.5 ± 1.0 to 145.0 ± 0.8 million years ago (Ma), which is preserved in Upper Jurassic strata.Owen 1987. In European lithostratigraphy, the name ...

Early Cretaceous The Early Cretaceous ( geochronological name) or the Lower Cretaceous (chronostratigraphic name), is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 145 Ma to 100.5 Ma. Geology Pro ...

in age. The genus was first named and described in a paper written in 1877 by

Othniel Charles Marsh Othniel Charles Marsh (October 29, 1831 – March 18, 1899) was an American professor of Paleontology in Yale College and President of the National Academy of Sciences. He was one of the preeminent scientists in the field of paleontology. Among h ...

.Marsh, O. C. (1877). Notice of some new vertebrate fossils. ''American Journal of Arts and Sciences'' 14:249-256

Discovery and etymology

The generic name, derived from Greek διπλόος, ''diploos'', "double", probably refers to the "biconcave vertebrae" Marsh mentions as a distinctive trait compared to modern forms. 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 ''Diplosaurus felix''.Williston, S. W. (1906). American amphicoelian crocodiles. ''The Journal of Geology'', ''14''(1), 1-17.Norell, M. A., & Storrs, G. W. (1989)
Postilla Number 203
The species was named on a heavily eroded skull roof and several postcranial elements, including a partial humerus, though the fossils have yet to be properly diagnosed. The fossils had been collected the same year by

Benjamin Franklin Mudge Benjamin Franklin Mudge (August 11, 1817 – November 21, 1879) was an American lawyer, geologist and teacher. Briefly the mayor of Lynn, Massachusetts, he later moved to Kansas where he was appointed the first State Geologist. He led the fi ...

and others during a Yale expedition to

Morrison, Colorado The Town of Morrison is a Colorado municipalities#Home rule municipality, home rule municipality in Jefferson County, Colorado, Jefferson County, Colorado, United States. The population was 428 at the 2010 United States Census, 2010 census. Red R ...

, one of the first dinosaur-bearing battle grounds of Othniel Marsh’s competition with

Edward Drinker Cope Edward Drinker Cope (July 28, 1840 – April 12, 1897) was an American zoologist, paleontologist, comparative anatomist, herpetologist, and ichthyologist. Born to a wealthy Quaker family, Cope distinguished himself as a child prodigy interested ...

. In 1890

Karl Alfred von Zittel Karl Alfred Ritter von Zittel (25 September 1839 – 5 January 1904) was a German palaeontologist best known for his ''Handbuch der Palaeontologie'' (1876–1880). Biography Karl Alfred von Zittel was born in Bahlingen in the Grand Duchy o ...

recombined this with ''

Goniopholis ''Goniopholis'' (meaning "angled scale") is an extinct genus of goniopholidid crocodyliform that lived in Europe and Africa during the Late Jurassic and Early Cretaceous. Being semi-aquatic it is very similar to modern crocodiles. It ranged from ...

'' into a ''Goniopholis felix'', but today this is generally rejected. Along with ''D. felix'' (sometimes misspelled ''D. felise''), a second species of ''Diplosaurus'' was constructed in 1877 by Marsh after he recombined '' Hyposaurus vebbii'', named by

in 1874, with ''Diplosaurus'' into a new combination, ''Diplosaurus vebbii''. Cope had named the species on a vertebra collected by

Kansas Kansas () is a state in the Midwestern United States. Its capital is Topeka, and its largest city is Wichita. Kansas is a landlocked state bordered by Nebraska to the north; Missouri to the east; Oklahoma to the south; and Colorado to the ...

railway worker and politician William C. Webb in 1871,Cope, E. D. (1875). The Vertebrata of Cretaceous formations of the West. ''Report of the United States Geological Survey of the territories''.Everhart, M. J. (2016). William E. Webb–Civil War correspondent, railroad land baron, town founder, Kansas legislator, adventurer, fossil collector, author. ''Transactions of the Kansas Academy of Science'', 179-192. though the fossil has since been lost. The fossil was even reported on in the newspaper ''Harpers Monthly'' and described as an long crocodilian. ''D. nanus'' was named by Marsh in 1895 based on a right humerus but is now considered to be a

nomen dubium In binomial nomenclature, a ''nomen dubium'' (Latin for "doubtful name", plural ''nomina dubia'') is a scientific name that is of unknown or doubtful application. Zoology In case of a ''nomen dubium'' it may be impossible to determine whether a s ...

. The humerus had been collected by Marsh earlier in 1870 in the older

Sundance Formation The Sundance Formation is a western North American sequence of Middle Jurassic to Upper Jurassic age Dating from the Bathonian to the Oxfordian, around 168-157 Ma, It is up to 100 metres thick and consists of marine shale, sandy shale, sandst ...

deposits in the

Green River Basin Green is the color between cyan and yellow on the visible spectrum. It is evoked by light which has a dominant wavelength of roughly 495570 nm. In subtractive color systems, used in painting and color printing, it is created by a combina ...

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 it ...

References

Late Jurassic crocodylomorphs of North America Early Cretaceous crocodylomorphs of North America Late Jurassic reptiles of North America Morrison fauna Early Cretaceous reptiles of North America Prehistoric pseudosuchian genera {{Jurassic-reptile-stub