''Thespesius'' (meaning "wondrous one") is a dubious

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

hadrosaurid Hadrosaurids (), also hadrosaurs or duck-billed dinosaurs, are members of the ornithischian family Hadrosauridae. This group is known as the duck-billed dinosaurs for the flat duck-bill appearance of the bones in their snouts. The ornithopod fami ...

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic Geological period, period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the #Evolutio ...

from the late Maastrichtian-age

Upper Cretaceous The Late Cretaceous (100.5–66 Ma) is the more recent of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''cret ...

Lance Formation The Lance (Creek) Formation is a division of Late Cretaceous (dating to about 69–66 Ma) rocks in the western United States. Named after Lance Creek, Wyoming, the microvertebrate fossils and dinosaurs represent important components of the lates ...

South Dakota South Dakota (; Sioux language, Sioux: , ) is a U.S. state, state in the West North Central states, North Central region of the United States. It is also part of the Great Plains. South Dakota is named after the Dakota people, Dakota Sioux ...

History

In 1855 geologist

Ferdinand Vandeveer Hayden Ferdinand Vandeveer Hayden (September 7, 1829 – December 22, 1887) was an American geologist noted for his pioneering surveying expeditions of the Rocky Mountains in the late 19th century. He was also a physician who served with the Union A ...

sent a number of fossils to

paleontologist Paleontology, also spelled as palaeontology or palæontology, is the scientific study of the life of the past, mainly but not exclusively through the study of fossils. Paleontologists use fossils as a means to classify organisms, measure geolo ...

Joseph Leidy Joseph Mellick Leidy (September 9, 1823 – April 30, 1891) was an American paleontologist, parasitologist and anatomist. Leidy was professor of anatomy at the University of Pennsylvania, later becoming a professor of natural history at Swarth ...

Philadelphia Philadelphia ( ), colloquially referred to as Philly, is the List of municipalities in Pennsylvania, most populous city in the U.S. state of Pennsylvania and the List of United States cities by population, sixth-most populous city in the Unit ...

. Hayden had collected them from the surface of a rock formation then known as the Great Lignite Formation (now recognized as part of the Lance Formation) in the

Nebraska Territory The Territory of Nebraska was an organized incorporated territory of the United States that existed from May 30, 1854, until March 1, 1867, when the final extent of the territory was admitted to the Union as the state of Nebraska. The Nebrask ...

, near the Grand River (present-day

). Among them were two caudal

vertebra Each vertebra (: vertebrae) is an irregular bone with a complex structure composed of bone and some hyaline cartilage, that make up the vertebral column or spine, of vertebrates. The proportions of the vertebrae differ according to their spina ...

e and a

phalanx The phalanx (: phalanxes or phalanges) was a rectangular mass military formation, usually composed entirely of heavy infantry armed with spears, pikes, sarissas, or similar polearms tightly packed together. The term is particularly used t ...

. In 1856 Leidy named the

type species In International_Code_of_Zoological_Nomenclature, 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 spe ...

''Thespesius occidentalis'' for these three bones.Leidy, J. (1856). "Notice of extinct Vertebrata, discovered by F. V. Hayden during the expedition to the Sioux country under the command of Lieut. G.K. Warren." ''Proceedings of the Academy of Natural Science Philadelphia'', 8(December 30): 311-312. The generic name is derived from Greek θεσπεσιος, ''thespesios'', "wondrous", because of the colossal size of the remains. Leidy avoided using the suffix "saurus" in the genus name because Vandeveer Hayden had claimed the bones came from a layer from the

Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

so there was a chance that the animal would turn out to be a

mammal A mammal () is a vertebrate animal of the Class (biology), class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three ...

, though Leidy himself was convinced it was a dinosaurian. The

specific name Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...

means "western" in

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

. The caudal vertebrae, USNM 219 and USNM 221, and the middle toe phalanx, USNM 220, form the original

syntype In biological nomenclature, a syntype is any one of two or more biological types that is listed in a description of a taxon where no holotype was designated. Precise definitions of this and related terms for types have been established as part o ...

series.

Classification

Like ''

Trachodon ''Trachodon'' (meaning "rough tooth") is a dubious genus of hadrosaurid dinosaur based on teeth from the Campanian-age Upper Cretaceous Judith River Formation of Montana, U.S.Leidy, J. (1856). "Notice of remains of extinct reptiles and fishes, ...

'', another duckbill genus named by

, ''Thespesius'' is a historically-important genus with a convoluted taxonomy that has been all but abandoned by modern dinosaur

s. Around 1900 the name was used by some authors to indicate all late Maastrichtian hadrosaurids in North America.Creisler, B.S. (2007). "Deciphering duckbills." Pp. 185-210 in Carpenter, K. (ed.), ''Horns and Beaks: Ceratopsian and Ornithopod Dinosaurs''. Bloomington and Indianapolis: Indiana University Press. In 1875, E.D. Cope stated that he considered ''Agathaumas milo'', known from partial limb bones and some vertebrae, to be a synonym of ''T. occidentalis'' (which he considered a species of ''

Hadrosaurus ''Hadrosaurus'' (; ) is a genus of hadrosaurid ornithopod dinosaurs that lived in North America during the Late Cretaceous Period in what is now the Woodbury Formation in New Jersey about 83.6 to 77.9 Ma. The holotype specimen was found in flu ...

'' at the time).Cope, E. D. (1875). ''Report on the vertebrate paleontology of Colorado''. US Government Printing Office. In 1900, a short piece published in ''Science'' by F.A. Lucas noted that Leidy's original ''Thespesius occidentalis'' fossils were indistinguishable from more complete specimens which had been referred in the late 1800s to the species ''

Claosaurus annectens ''Edmontosaurus annectens'' (meaning "connected lizard from Edmonton"), often colloquially and historically known as ''Anatosaurus'' (meaning "duck lizard"), is a species of flat-headed saurolophine hadrosaurid dinosaur from the late Maastrichtia ...

''. Therefore, Lucas argued, the name ''T. occidentalis'' should be used for this animal.Lucas, F.A. (1900). "Paleontological Notes." ''Science'', 12(308): 809-810

/ref> Lucas' opinion was supported by Charles W. Gilmore in a 1915 paper for ''Science'' re-evaluating the use of the genus ''Trachodon''. A wide variety of hadrosaurid species had been classified as ''Trachodon'' or "trachodonts", most notably the large "duck-billed" specimens collected by E.D. Cope and mounted in the

American Museum of Natural History The American Museum of Natural History (AMNH) is a natural history museum on the Upper West Side of Manhattan in New York City. Located in Theodore Roosevelt Park, across the street from Central Park, the museum complex comprises 21 interconn ...

. Gilmore noted that the holotype fossils of ''T. occidentalis'' were "inadequate", but that geologic work showed that they undoubtedly came from the same fossil beds as ''Claosaurus annectens'', and that therefore the older name (''T. occidentalis'') should be used for the Lance-aged "trachodonts."Gilmore, C.W. (1915). "On the Genus ''Trachodon.''" ''Science'', 41(1061): 658-660. Many later researchers, including L.S. Russell and Charles M. Sternberg, continued to use the names ''Thespesius occidentalis'' or ''Thespesius annectens'' for the Lance hadrosaurids through the 1920s and 1930s.Russell, L.S. (1930). "Upper Cretaceous dinosaur faunas of North America." ''Proceedings of the American Philosophical Society'', 69(1): 133-159.Sternberg, C.M. (1936). "The systematic position of ''Trachodon''." ''Journal of Paleontology'', 10(7): 652-655.Sternberg, C.M. (1939). "Were there Proboscis-bearing Dinosaurs? Discussion of Cranial Protuberances in the Hadrosauridae." ''Journal of Natural History'', 3(17): 556-560. However, as early as 1913, paleontologist Lawrence Lambe regarded the type fossils of ''Thespesius occidentalis'' as inadequate and that any inferences based on them were too conjectural, as was the case for ''Trachodon''. In an influential 1942 paper on hadrosaurids by Richard S. Lull and Nelda E. Wright, the authors classified most specimens of ''Thespesius annectens'' in the new genus '' Anatosaurus'', and referred Cope's giant "duck-billed" specimens to ''Anatosaurus copei''. Though they noted that ''T. occidentalis'' could possibly be distinguished from ''Anatosaurus'' based on its shorter tail vertebrae, they ultimately agreed with Lambe that, despite its historical importance, ''Thespesius occidentalis'' was too incomplete for good comparison.Lull, R.S. & Wright, N.E. (1942). "Hadrosaurian dinosaurs of North America." ''Geological Society of America Special Papers'', 40: 1-272. It has been generally ignored as 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 ...

'' ever since. A referred species of ''Thespesius'', ''T. saskatchewanensis'', was named by Sternberg in 1926,Sternberg, C.M. (1926). A new species of ''Thespesius'' from the Lance Formation of Saskatchewan. ''Canada Department of Mines Geological Survey Bulletin (Geological Series)'' 44(46):73-84. but Nicolás Campione and David Evans found that it was a synonym of ''

Edmontosaurus annectens ''Edmontosaurus annectens'' (meaning "connected lizard from Edmonton"), often colloquially and historically known as ''Anatosaurus'' (meaning "duck lizard"), is a species of flat-headed Saurolophinae, saurolophine hadrosaurid dinosaur from the la ...

'' in a 2011 study of edmontosaur diversity. Campione and Evans also found ''Thespesius edmontoni'', named by Gilmore in 1924,Gilmore, C.W. (1924). A new species of hadrosaurian dinosaur from the Edmonton Formation (Cretaceous) of Alberta. ''Canada Department of Mines Geological Survey Bulletin (Geological Series)'' 38(43):13-26. to be a synonym of ''

Edmontosaurus regalis ''Edmontosaurus regalis'' is a species of comb-crested hadrosaurid dinosaur. Fossils of ''E. regalis'' have been found in rocks of western North America that date from the late Campanian age of the Cretaceous Geologic time scale#Terminology, Peri ...

''.

References

{{Taxonbar, from=Q762249 Hadrosauridae Dinosaur genera Maastrichtian dinosaurs Lance Formation Taxa named by Joseph Leidy Fossil taxa described in 1856 Dinosaurs of the United States

History

Classification

See also

References