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

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 ...

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 with ...

from the Late Jurassic of

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 b ...

. 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, althou ...

Lucas Ewbank 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 bec ...

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 fossi ...

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 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 "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 descr ...

'' 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 several ...

, 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'', 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 however, showed that ''Cryptosaurus'' is an ankylosaurian 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 ''Cryptosaurus'' (meaning "hidden lizard") is a dubious genus of dinosaur known from a partial femur from the Late Jurassic of England. The sole species is ''Cryptosaurus eumerus''. The femur was found by the geologist Lucas Ewbank and donated ...

'' 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