Editing Ceratosaurus (section)

==History of discovery==
===Holotype specimen of ''C.  nasicornis''===
[[File:CeratosaurusSkeleton.jpg|thumb|alt=Original skeletal reconstruction by Othniel Charles Marsh, 1892|''C. nasicornis'' skeleton restoration by [[Othniel Charles Marsh]] from 1896, depicted in an erroneous upright position and with excess vertebrae in the spine resulting in an overly elongated trunk]]
The first specimen, holotype USNM 4735, was discovered and excavated by farmer Marshall Parker Felch in 1883 and 1884.<ref name="brinkman2000"/> Found in articulation, with the bones still connected to each other, it was nearly complete, including the skull. Significant missing parts include an unknown number of vertebrae, all but the last ribs of the trunk, the [[humerus|humeri]] (upper arm bones), the distal finger bones of both hands, most of the right  arm, most of the left leg, and most of the feet.<ref name="gilmore-20"/>{{rp|77}} The specimen was found encased in hard sandstone, leading to the skull and spine being heavily distorted during [[fossil]]ization.<ref name="gilmore-20"/>{{rp|2,114}} The site of discovery, located in the [[Garden Park, Colorado|Garden Park]] area north of [[Cañon City, Colorado]], and known as the Felch Quarry 1, is regarded as one of the richest fossil sites of the [[Morrison Formation]]. Numerous dinosaur fossils had been recovered from this quarry even before the discovery of ''Ceratosaurus'', most notably a nearly complete specimen of ''Allosaurus'' (USNM 4734) in 1883 and 1884.<ref name="gilmore-20"/>{{rp|7,114}}

After excavation, the specimen was shipped to the [[Peabody Museum of Natural History]] in [[New Haven, Connecticut|New Haven]], where it was studied by Marsh, who described it as the new genus and species ''Ceratosaurus nasicornis'' in 1884.<ref name="marsh-84" /><ref name="gilmore-20"/>{{rp|114}} The name ''Ceratosaurus'' may be translated as "horn lizard" (from the [[Ancient Greek|Greek]] words {{lang|grc|κερας/κερατος}}, '' {{lang|grc-Latn|keras/keratos}}''—"horn" and {{lang|grc|σαυρος}}/''{{lang|grc-Latn|sauros}}''—"lizard")<ref name="glut-97"/> and ''nasicornis'' with "nose horn" (from the [[Latin]] words ''nasus''—"nose" and ''cornu''—"horn").<ref>{{cite book|last1 = Simpson | first1 = D.P.| title = Cassell's Latin Dictionary  | publisher = Cassell Ltd.| year = 1979|orig-year=1854|edition = 5|location = London|pages=153, 387| isbn=978-0-304-52257-6}}</ref> Given the completeness of the specimen, the newly described genus was, at the time, the best-known theropod discovered in America. In 1898 and 1899, the specimen was transferred to the [[National Museum of Natural History]] in [[Washington, DC]], along with many other fossils originally described by Marsh. Only part of this material was fully prepared when it arrived in Washington. Subsequent preparation lasted from 1911 to the end of 1918. Packaging and shipment from New Haven to Washington caused some damage to the ''Ceratosaurus'' specimen.<ref name="gilmore-20"/>{{rp|2,114}} In 1920, [[Charles W. Gilmore|Charles Gilmore]] published an extensive redescription of this and the other theropod specimens received from New Haven, including the nearly complete ''Allosaurus'' specimen recovered from the same quarry.<ref name="gilmore-20"/>{{rp|2}}

[[File:Ceratosaurus nasicornis reconstruction gilmore 1920.png|thumb|left|alt=Skeletal diagram by Charles Gilmore (1920) showing known elements|Reconstruction of the holotype specimen of ''C. nasicornis'' by [[Charles W. Gilmore]], 1920, showing known elements]]
In an 1892 paper, Marsh published the first skeletal reconstruction of ''Ceratosaurus'', which depicts the animal at {{convert|22|ft|abbr=on}} in length and {{convert|12|ft|abbr=on}} in height.<ref name="marsh-92"/> As noted by Gilmore in 1920, the trunk was depicted much too long in this reconstruction, incorporating at least six dorsal vertebrae too many. This error was repeated in several subsequent publications, including the first life reconstruction, which was drawn in 1899 by Frank Bond under the guidance of [[Charles R. Knight]], but not published until 1920. A more accurate life reconstruction, published in 1901, was produced by [[Joseph M. Gleeson]], again under Knight's supervision. The holotype was mounted by Gilmore in 1910 and 1911. Since then, it was exhibited at the National Museum of Natural History. Most early reconstructions show ''Ceratosaurus'' in an upright posture, with the tail dragging on the ground.<ref name="gilmore-20"/>{{rp|115–116}} Gilmore's mount of the holotype, in contrast, was very ahead of its time.<ref name="paul_1988"/>{{rp|276}} Inspired by the upper thigh bones, which were found angled against the lower leg, he depicted the mount as a running animal with a horizontal posture and a tail that did not make contact with the ground. Because of the strong flattening of the fossils, Gilmore mounted the specimen, not as a free-standing skeleton, but as a [[relief|bas-relief]] within an artificial wall.<ref name="gilmore-20"/>{{rp|114}} With the bones being partly embedded in a plaque, scientific access was limited. In the course of the renovation of the museum's dinosaur exhibition between 2014 and 2019, the specimen was dismantled and freed from the encasing plaque.<ref>{{cite news|url=https://www.washingtonpost.com/lifestyle/style/david-koch-donates-35-million-to-national-museum-of-natural-history-for-dinosaur-hall/2012/05/03/gIQAIjT3yT_story.html |first=T. |last=Jacqueline |title=David Koch Donates $35 Million to National Museum of Natural History for Dinosaur Hall |newspaper=The Washington Post |date=May 3, 2012 | access-date=December 4, 2017|url-access=subscription}}</ref><ref name="smithonian">{{cite web| title = The Good, Bad and Ugly: Dismantling Historic Fossil Displays, Part Two| work = Digging the Fossil Record: Paleobiology at the Smithsonian| publisher = Smithsonian National Museum of Natural History| access-date = December 4, 2017| url = http://nmnh.typepad.com/smithsonian_fossils/2016/01/historic-armatures-part-two.html| archive-url = https://web.archive.org/web/20171010003751/http://nmnh.typepad.com/smithsonian_fossils/2016/01/historic-armatures-part-two.html| archive-date = October 10, 2017| url-status = dead}}</ref> In the new exhibition, which was set to open in 2019, the mount was planned to be replaced by a free-standing cast and the original bones were to be stored in the museum collection to allow full access for scientists.<ref name="smithonian"/>

[[File:Osteology of the carnivorous Dinosauria in the United States National museum BHL40623218 edited (cropped).jpg|thumb|right|alt=The first life reconstruction, drawn by Frank Bond in 1899|Probably the first life restoration of ''Ceratosaurus'', drawn in 1899 by Frank Bond under the guidance of Charles R. Knight, but not published until 1920]]

===Additional finds in North America===
After the discovery of the holotype of ''C. nasicornis'', a significant ''Ceratosaurus'' find was not made until the early 1960s, when paleontologist [[James Henry Madsen|James Madsen]] and his team unearthed a fragmentary, disarticulated skeleton including the skull (UMNH VP 5278) in the Cleveland-Lloyd Dinosaur Quarry of Utah. This find represents one of the largest-known ''Ceratosaurus'' specimens.<ref name="madsen2000"/>{{rp|21}} A second, articulated specimen including the skull (MWC 1) was discovered in 1976 by Thor Erikson, the son of paleontologist Lance Erikson, near [[Fruita, Colorado]].<ref name="glut-97"/> A fairly complete specimen, it lacks lower jaws, forearms, and [[Gastralium|gastralia]]. The skull, although reasonably complete, was found disarticulated and is strongly flattened sideways. Although it was a large individual, it had not yet reached adult size, as indicated by unfused sutures between the skull bones.<ref name="madsen2000"/>{{rp|2–3}} Scientifically accurate three-dimensional reconstructions of the skull for use in museum exhibits were produced using a complicated process including molding and casting of the individual original bones, correction of deformities, reconstruction of missing parts, assembly of the bone casts into their proper position, and painting to match the original color of the bones.<ref name="tidwell1996"/>

Both the Fruita and Cleveland-Lloyd specimens were described by Madsen and [[Samuel Paul Welles]] in a 2000 monograph, with the Utah specimen being assigned to the new species ''C. dentisulcatus'' and the Colorado specimen being assigned to the new species ''C. magnicornis''.<ref name="madsen2000"/> The name ''dentisulcatus'' refers to the parallel grooves present on the inner sides of the premaxillary teeth and the first three teeth of the lower jaw in that specimen. ''Magnicornis'' points to the larger nasal horn.<ref name="madsen2000"/>{{rp|2,21}} The [[Valid name (zoology)|validity]] of both species, however, was questioned in subsequent publications. Brooks Britt and colleagues, in 2000, claimed that the ''C. nasicornis'' holotype was in fact a juvenile individual, with the two larger species representing the adult state of a single species.<ref name="britt2000"/> Oliver Rauhut, in 2003, and Matthew Carrano and Scott Sampson, in 2008, considered the anatomical differences cited by Madsen and Welles to support these additional species to represent [[ontogeny|ontogenetic]] (age-related) or individual variation.<ref name="rauhut2003"/><ref name="carrano2008"/>{{rp|192}}

{{multiple image
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|image1 = Ceratosaurus juvenile museum of ancient life 3.jpg
|alt1 = Fragmentary skeleton of a juvenile at the North American Museum of Ancient Life
|image2 = Ceratosaurus juvenile museum of ancient life 2.jpg
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|footer = Partial juvenile specimen (hind and front parts), [[North American Museum of Ancient Life]]
}}

A further specimen (BYUVP 12893) was discovered in 1992 in the Agate Basin Quarry southeast of [[Moore, Utah]], but still awaits description. The specimen, considered the largest known from the genus, includes the front half of a skull, seven fragmentary pelvic dorsal vertebrae, and an articulated pelvis and sacrum.<ref name="carrano2008"/>{{rp|192}}<ref name="madsen2000"/>{{rp|36}} In 1999, Britt reported the discovery of a ''Ceratosaurus'' skeleton belonging to a juvenile individual. Discovered in [[Bone Cabin Quarry]] in Wyoming, it is 34% smaller than the ''C. nasicornis'' holotype and consists of a complete skull as well as 30% of the remainder of the skeleton including a complete pelvis.<ref name="britt1999"/>

Besides these five skeletal finds, fragmentary ''Ceratosaurus'' remains have been reported from various localities from stratigraphic zones 2 and 4-6 of the Morrison Formation,<ref name="foster-appendix"/> including some of the major fossil sites of the formation. [[Dinosaur National Monument]], Utah, yielded an isolated right premaxilla (DNM 972). A large shoulder blade (scapulocoracoid) was reported from [[Como Bluff]] in [[Wyoming]]. Another specimen stems from the [[Dry Mesa Quarry]] of Colorado and includes a left scapulocoracoid, as well as fragments of vertebrae and limb bones. In Mygatt Moore Quarry, Colorado, the genus is known from teeth.<ref name="madsen2000"/>{{rp|36}}

===Finds outside North America===
From 1909 to 1913, German expeditions of the [[Berlin]] [[Museum für Naturkunde]] uncovered a diverse dinosaur fauna from the [[Tendaguru Formation]] in [[German East Africa]], in what is now [[Tanzania]].<ref name="zils1995"/> Although commonly considered the most important African dinosaur locality,<ref name="zils1995"/> large theropod dinosaurs are only known through few and very fragmentary remains.<ref name="janensch1925"/> In 1920, German paleontologist [[Werner Janensch]] assigned several dorsal vertebrae from the quarry "TL" to ''Ceratosaurus'', as ''Ceratosaurus'' sp. (of uncertain species). In 1925, Janensch named a new species of ''Ceratosaurus'', ''C. roechlingi'', based on fragmentary remains from the quarry "Mw" encompassing a quadrate bone, a fibula, fragmentary caudal vertebrae, and other fragments. This specimen stems from an individual substantially larger than the ''C. nasicornis'' holotype.<ref name="janensch1925"/>

[[File:Outdated Ceratosaurus.jpg|thumb|alt=Early life reconstruction by Joseph M. Gleeson, 1901|Restoration of ''C. nasicornis'' by [[Joseph M. Gleeson]] from 1901, made under supervision of [[Charles R. Knight]].]]
In their 2000 monograph, Madsen and Welles confirmed the assignment of these finds to ''Ceratosaurus''. In addition, they ascribed several teeth to the genus, which had originally been described by Janensch as a possible species of ''[[Allosaurus|Labrosaurus]]'', ''Labrosaurus'' (?) ''stechowi''.<ref name="madsen2000"/> Other authors questioned the assignment of any of the Tendaguru finds to ''Ceratosaurus'', noting that none of these specimens displays features diagnostic for that genus.<ref name="rowe-gauthier-90"/><ref name="tykoski-et-al-04"/>{{rp|66}}<ref name="carrano2008"/>{{rp|192}}<ref name="rauhut2011"/> In 2011, Rauhut found both ''C. roechlingi'' and ''Labrosaurus'' (?) ''stechowi'' to be possible ceratosaurids, but found them to be undiagnostic at genus level and designated them as ''[[Nomen dubium|nomina dubia]]'' (doubtful names).<ref name="rauhut2011"/> In 1990, Timothy Rowe and [[Jacques Gauthier]] mentioned yet another ''Ceratosaurus'' species from Tendaguru, ''Ceratosaurus ingens'', which purportedly was erected by Janensch in 1920 and was based on 25 isolated, very large teeth up to {{convert|15|cm|abbr=on}} in length.<ref name="rowe-gauthier-90"/><ref name="janensch1925"/> However, Janensch assigned this species to ''[[Megalosaurus]]'', not to ''Ceratosaurus''. Therefore, this name might be a simple copying error.<ref name="madsen2000"/>{{rp|37}}<ref name="janensch1925"/> Rauhut, in 2011, showed that ''Megalosaurus ingens'' was not closely related to either ''Megalosaurus'' or ''Ceratosaurus'', but possibly represents a [[carcharodontosaurid]] instead.<ref name="rauhut2011"/>

In 2000 and 2006, paleontologists led by [[Octávio Mateus]] described a find from the [[Lourinhã Formation]] of central-west [[Portugal]] (ML 352) as a new specimen of ''Ceratosaurus'', consisting of a right [[femur]] (upper thigh bone), a left [[tibia]] (shin bone), and several isolated teeth recovered from the cliffs of Valmitão beach, between the municipalities of [[Lourinhã]] and [[Torres Vedras]].<ref name="mateus2000"/><ref name="mateus2006"/> The bones were found embedded in yellow to brown, fine-grained sandstones, which were deposited by rivers as floodplain deposits and belong to the lower levels of the Porto Novo Member, which is thought to be late [[Kimmeridgian]] in age. Additional bones of this individual (SHN (JJS)-65), including a left femur, a right tibia, and a partial left [[fibula]] (calf bone), were since exposed due to progressing [[Coastal erosion|cliff erosion]]. Although initially part of a private collection, these additional elements became officially curated after the private collection was donated to the Sociedade de História Natural in Torres Vedras and were described in detail in 2015.<ref name="malafaia2015"/> The specimen was ascribed to the species ''Ceratosaurus dentisulcatus'' by Mateus and colleagues in 2006.<ref name="mateus2006"/> A 2008 review by Carrano and Sampson confirmed the assignment to ''Ceratosaurus'', but concluded that the assignment to any specific species is not possible at present.<ref name="carrano2008"/>{{rp|192}} In 2015, Elisabete Malafaia and colleagues, who questioned the validity of ''C. dentisulcatus'', assigned the specimen to ''Ceratosaurus'' aff. ''Ceratosaurus nasicornis''.<ref name="malafaia2015"/>

Other reports include a single tooth found in [[Moutier]], [[Switzerland]]. Originally named by Janensch in 1920 as ''Labrosaurus meriani'', the tooth was later assigned ''Ceratosaurus'' sp. (of unknown species) by Madsen and Welles.<ref name="madsen2000"/>{{rp|35–36}} In 2008, Matías Soto and Daniel Perea described teeth from the [[Tacuarembó Formation]] in [[Uruguay]], including a presumed premaxillary tooth crown. This shows vertical striations on its inner side and lacks denticles on its front edge. These features are, in this combination, only known from ''Ceratosaurus''. The authors, however, stressed that an assignment to ''Ceratosaurus'' is infeasible because the remains are scant and note that the assignment of the European and African material to ''Ceratosaurus'' has to be viewed with caution.<ref name="soto2008"/> In 2020, Soto and colleagues described additional ''Ceratosaurus'' teeth from the same formation that further support their earlier interpretation.<ref>{{Cite journal|last1=Soto|first1=Matías|last2=Toriño|first2=Pablo|last3=Perea|first3=Daniel|date=November 1, 2020|title=''Ceratosaurus'' (Theropoda, Ceratosauria) teeth from the Tacuarembó Formation (Late Jurassic, Uruguay)|journal=Journal of South American Earth Sciences|language=en|volume=103|pages=102781|doi=10.1016/j.jsames.2020.102781|bibcode=2020JSAES.10302781S|s2cid=224842133|issn=0895-9811}}</ref>