''Cryptosaurus'' (meaning "hidden lizard") is a dubious

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 ...

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

known from a partial

femur The femur (; ), or thigh bone, is the proximal bone of the hindlimb in tetrapod vertebrates. The head of the femur articulates with the acetabulum in the pelvic bone forming the hip joint, while the distal part of the femur articulates wit ...

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 ...

England England is a country that is part of the United Kingdom. It shares land borders with Wales to its west and Scotland to its north. The Irish Sea lies northwest and the Celtic Sea to the southwest. It is separated from continental Europe ...

. The sole species is ''Cryptosaurus eumerus''. The femur was found by the

geologist A geologist is a scientist who studies the solid, liquid, and gaseous matter that constitutes Earth and other terrestrial planets, as well as the processes that shape them. Geologists usually study geology, earth science, or geophysics, alt ...

Lucas Ewbank Lucas or LUCAS may refer to: People * Lucas (surname) * Lucas (given name) Arts and entertainment * Luca Family Singers, also known as "lucas ligner en torsk" * ''Lucas'' (album) (2007), an album by Skeletons and the Kings of All Cities * ''Lu ...

and donated by him to the

Woodwardian Museum The Sedgwick Museum of Earth Sciences, is the geology museum of the University of Cambridge. It is part of the Department of Earth Sciences and is located on the university's Downing Site in Downing Street, central Cambridge, England. The Sedgw ...

Cambridge Cambridge ( ) is a university city and the county town in Cambridgeshire, England. It is located on the River Cam approximately north of London. As of the 2021 United Kingdom census, the population of Cambridge was 145,700. Cambridge beca ...

in 1869. ''Cryptosaurus'' was the same year named by British

paleontologist Paleontology (), also spelled palaeontology or palæontology, is the scientific study of life that existed prior to, and sometimes including, the start of the Holocene epoch (roughly 11,700 years before present). It includes the study of foss ...

Harry Seeley Harry Govier Seeley (18 February 1839 – 8 January 1909) was a British paleontologist. Early life Seeley was born in London on 18 February 1839, the second son of Richard Hovill Seeley, a goldsmith, and his second wife Mary Govier. When his fat ...

; 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 ''Cryptosaurus eumerus''. The genus name is derived from Greek ''kryptos'', "hidden", a reference to the rarity of the find. The specific name means "well-formed thigh" in Greek, a reference to the stout build of the bone. The description of 1869, part of a catalogue of the

Cambridge University , mottoeng = Literal: From here, light and sacred draughts. Non literal: From this place, we gain enlightenment and precious knowledge. , established = , other_name = The Chancellor, Masters and Schola ...

collection, was rather minimal, consisting of the single sentence "On Shelf g is temporarily placed the femur of a Dinosaur from the Oxford Clay, Cryptosaurus eumerus". From this it is sometimes concluded that the name remained a ''

nomen nudum In taxonomy, a ''nomen nudum'' ('naked name'; plural ''nomina nuda'') is a designation which looks exactly like a scientific name of an organism, and may have originally been intended to be one, but it has not been published with an adequate des ...

'' until a full description by Seeley in 1875. 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 seve ...

, CAMSM J.46882, was discovered in the ''Great Gransden brick pit'', in strata of the

Ampthill Clay The Ampthill Clay is a Mesozoic geologic formation in southern England. Dinosaur remains diagnostic to the genus level are among the fossils that have been recovered from the formation.Weishampel, et al. (2004). "Dinosaur distribution." Pp. 517- ...

Formation, dating from the upper Oxfordian. The right femur is about 33 centimetres long and has a thick shaft. It belonged to an adult or at least subadult individual, meaning that the species was rather small. Seeley thought that ''Cryptosaurus'' was a relative of ''

Iguanodon ''Iguanodon'' ( ; meaning 'iguana-tooth'), named in 1825, is a genus of iguanodontian dinosaur. While many species have been classified in the genus ''Iguanodon'', dating from the late Jurassic Period to the early Cretaceous Period of Asia, ...

'', the first such discovered from the Oxford Clay — hence the generic name.

Friedrich von Huene Friedrich von Huene, born Friedrich Richard von Hoinigen, (March 22, 1875 – April 4, 1969) was a German paleontologist who renamed more dinosaurs in the early 20th century than anyone else in Europe. He also made key contributions about v ...

classified it in the Camptosauridae in 1909. The work of

Peter Galton Peter Malcolm Galton (born 14 March 1942 in London) is a British vertebrate paleontologist who has to date written or co-written about 190 papers in scientific journals or chapters in paleontology textbooks, especially on ornithischian and prosau ...

however, showed that ''Cryptosaurus'' is an

ankylosauria Ankylosauria is a group of herbivorous dinosaurs of the order Ornithischia. It includes the great majority of dinosaurs with armor in the form of bony osteoderms, similar to turtles. Ankylosaurs were bulky quadrupeds, with short, powerful limbs ...

n of unknown affinities. Today it is commonly 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 ...

'' because of the limited remains. ''Cryptosaurus'' was for a long time known as ''Cryptodraco'', which is an unnecessary replacement name. In 1889,

Richard Lydekker Richard Lydekker (; 25 July 1849 – 16 April 1915) was an English naturalist, geologist and writer of numerous books on natural history. Biography Richard Lydekker was born at Tavistock Square in London. His father was Gerard Wolfe Lydekker ...

renamed ''Cryptosaurus'' as he believed the name ''Cryptosaurus'' was already previously in use for another animal ('' Cystosaurus'' Geoffroy, described in 1832). This was in error, a mistake originally caused by a wrong spelling of ''Cystosaurus'' in the French ''Bibliothèque universelle des sciences, belles-lettres, et arts'', and the name ''Cryptosaurus'' has precedence.

References

Ankylosaurs Oxfordian life Late Jurassic dinosaurs of Europe Jurassic England Fossils of England Fossil taxa described in 1869 Taxa named by Harry Seeley Nomina dubia {{Jurassic-reptile-stub

See also

References