''Smitanosaurus'' (meaning "smith lizard") is a genus of

dicraeosaurid Dicraeosauridae is a family of diplodocoid sauropods who are the sister group to Diplodocidae. Dicraeosaurids are a part of the Flagellicaudata, along with Diplodocidae. Dicraeosauridae includes genera such as ''Amargasaurus'', ''Suuwassea'', ''D ...

sauropod Sauropoda (), whose members are known as sauropods (; from '' sauro-'' + '' -pod'', 'lizard-footed'), is a clade of saurischian ('lizard-hipped') dinosaurs. Sauropods had very long necks, long tails, small heads (relative to the rest of their bo ...

dinosaur from the

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 ...

Colorado Colorado (, other variants) is a state in the Mountain West subregion of the Western United States. It encompasses most of the Southern Rocky Mountains, as well as the northeastern portion of the Colorado Plateau and the western edge of t ...

. The genus contains one species, ''S. agilis'', originally assigned to the defunct genus ''

Morosaurus ''Camarasaurus'' ( ) was a genus of quadrupedal, herbivorous dinosaurs and is the most common North American sauropod fossil. Its fossil remains have been found in the Morrison Formation, dating to the Late Jurassic epoch (Kimmeridgian to Titho ...

''.

History

The species ''Morosaurus agilis'' was originally named 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 ...

in 1889 for a partial skull, proatlases, and three cervical vertebrae found in 1883 in the

Morrison Formation The Morrison Formation is a distinctive sequence of Late Jurassic, Upper Jurassic sedimentary rock found in the western United States which has been the most fertile source of dinosaur fossils in North America. It is composed of mudstone, sandsto ...

of Colorado. However, the genus ''Morosaurus'' was in 1907 reinterpreted as a

junior synonym The Botanical and Zoological Codes of nomenclature treat the concept of synonymy differently. * In botanical nomenclature, a synonym is a scientific name that applies to a taxon that (now) goes by a different scientific name. For example, Linna ...

of ''

Camarasaurus ''Camarasaurus'' ( ) was a genus of quadrupedal, herbivorous dinosaurs and is the most common North American sauropod fossil. Its fossil remains have been found in the Morrison Formation, dating to the Late Jurassic epoch (Kimmeridgian to Titho ...

'', and most of the species assigned to the former genus were reassigned to the latter. ''M. agilis'', on the other hand, was left defunct without a proper generic assignment. O. P. Hay. 1930.'' Second Bibliography and Catalogue of the Fossil Vertebrata of North America'' 390(II):1-1074 Over time comparisons have been drawn with ''

Haplocanthosaurus ''Haplocanthosaurus'' (meaning "simple spined lizard") is a genus of intermediate sauropod dinosaur. Two species, ''H. delfsi'' and ''H. priscus'', are known from incomplete fossil skeletons. It lived during the late Jurassic period (Kimmeridgia ...

'', ''

Diplodocus ''Diplodocus'' (, , or ) was a genus of diplodocid sauropod dinosaurs, whose fossils were first discovered in 1877 by S. W. Williston. The generic name, coined by Othniel Charles Marsh in 1878, is a neo-Latin term derived from Greek διπ� ...

'' and

brachiosaurids The Brachiosauridae ("arm lizards", from Greek ''brachion'' (βραχίων) = "arm" and ''sauros'' = "lizard") are a family or clade of herbivorous, quadrupedal sauropod dinosaurs. Brachiosaurids had long necks that enabled them to access the le ...

, but never with a phylogenetic analysis. Further preparation and analysis by Whitlock & Wilson, 2020, have since reinterpreted it as a dicraeosaurid, warranting the new genus name ''Smitanosaurus''. The new generic name means "smith lizard", from the

Old Saxon Old Saxon, also known as Old Low German, was a Germanic language and the earliest recorded form of Low German (spoken nowadays in Northern Germany, the northeastern Netherlands, southern Denmark, the Americas and parts of Eastern Europe). It i ...

''smitan'', referring to J. August Smith, who excavated and sketched the

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several ...

USNM 5384, as well as the

Smithsonian Institution The Smithsonian Institution ( ), or simply the Smithsonian, is a group of museums and education and research centers, the largest such complex in the world, created by the U.S. government "for the increase and diffusion of knowledge". Founded ...

, where the remains are stored.

Classification

Whitlock & Wilson's redescription marks the first time ''S. agilis'' has been added to a phylogenetic analysis. They recovered it as a member of Dicraeosauridae, making it one of the ever-growing number of North American dicraeosaurids. Their cladogram is shown below:

References

{{Taxonbar, from=Q104440015 Dicraeosaurids Late Jurassic dinosaurs of North America Dinosaurs of the Morrison Formation Fossil taxa described in 2020 Paleontology in Colorado