Regnosaurus
Encyclopedia
Regnosaurus is a genus
of herbivorous stegosaurian dinosaur
that lived during the Early Cretaceous
Period in what is now England
.
in Sussex
, and made part of the collection of the British Museum of Natural History. In 1839 Gideon Mantell
reported having noticed the fossil during a visit. Mantell soon came to the conclusion that the specimen represented the, until then unknown, lower jaw of his Iguanodon
, probably that of a juvenile. On 8 February 1841 he presented it as such to the Royal Society
. This interpretation was immediately challenged by Richard Owen
, who felt that any proof of a connection was lacking. In 1848, after several real jaws of Iguanodon had been discovered, Mantell changed his position, concluding it was a related but different genus or subgenus
, coining the name Regnosaurus Northamptoni. The generic name is derived from the Regni or Regnenses
, a British tribe inhabiting Sussex
. The specific name honours Spencer Compton, 2nd Marquess of Northampton
, the president of the Royal Society, who was about to resign. By present conventions, the type species
is written as Regnosaurus northamptoni.
Regnosaurus is known only from the holotype
BMNH 2422, a right mandibular (lower jaw) fragment, consisting of a third of the dentary and a part of the splenial
. The specimen is six inches long and shows fifteen tooth sockets. Also some replacement teeth are visible. Other bone fragments have sometimes been referred to Regnosaurus, such as a fossil pubis
recovered on the Isle of Wight
, but as these are of other parts of the body and a reasonably complete skeleton is lacking, the identity cannot be proven. The same is true for some dermal spikes reported by William Blows. Regnosaurus was probably a rather small animal, about 4 metres (13 feet) long.
assigned it to the Scelidosauridae. In 1909 Friedrich von Huene
classified it in the stegosaurian Omosauridae and in 1911 Alfred von Zittel assigned it to the Stegosauridae
but these groups then had a different content and also included armoured forms. In 1956 Alfred Romer
synonymised it with Hylaeosaurus
. An entirely different suggestion was made by John Ostrom
who surmised it might have been a sauropod.
The first to state that it was a stegosaurian in the modern sense was George Olshevsky
in 1993. This was confirmed by Paul Barret and Paul Upchurch in 1995 who concluded that it is a stegosaur similar to Huayangosaurus
, as the jaws are very similar. As the remains are so limited, many recent researchers have concluded Regnosaurus to be a nomen dubium
.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of herbivorous stegosaurian dinosaur
Dinosaur
Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...
that lived during the Early Cretaceous
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...
Period in what is now England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
.
Discovery and species
The fossil remains, a portion of the right lower jaw, were found near CuckfieldCuckfield
Cuckfield is a large village and civil parish in the Mid Sussex District of West Sussex, England, on the southern slopes of the Weald. It lies south of London, north of Brighton, and east northeast of the county town of Chichester. Nearby towns include Haywards Heath to the southeast and Burgess...
in Sussex
Sussex
Sussex , from the Old English Sūþsēaxe , is an historic county in South East England corresponding roughly in area to the ancient Kingdom of Sussex. It is bounded on the north by Surrey, east by Kent, south by the English Channel, and west by Hampshire, and is divided for local government into West...
, and made part of the collection of the British Museum of Natural History. In 1839 Gideon Mantell
Gideon Mantell
Gideon Algernon Mantell MRCS FRS was an English obstetrician, geologist and palaeontologist...
reported having noticed the fossil during a visit. Mantell soon came to the conclusion that the specimen represented the, until then unknown, lower jaw of his Iguanodon
Iguanodon
Iguanodon is a genus of ornithopod dinosaur that lived roughly halfway between the first of the swift bipedal hypsilophodontids and the ornithopods' culmination in the duck-billed dinosaurs...
, probably that of a juvenile. On 8 February 1841 he presented it as such to the Royal Society
Royal Society
The Royal Society of London for Improving Natural Knowledge, known simply as the Royal Society, is a learned society for science, and is possibly the oldest such society in existence. Founded in November 1660, it was granted a Royal Charter by King Charles II as the "Royal Society of London"...
. This interpretation was immediately challenged by Richard Owen
Richard Owen
Sir Richard Owen, FRS KCB was an English biologist, comparative anatomist and palaeontologist.Owen is probably best remembered today for coining the word Dinosauria and for his outspoken opposition to Charles Darwin's theory of evolution by natural selection...
, who felt that any proof of a connection was lacking. In 1848, after several real jaws of Iguanodon had been discovered, Mantell changed his position, concluding it was a related but different genus or subgenus
Subgenus
In biology, a subgenus is a taxonomic rank directly below genus.In zoology, a subgeneric name can be used independently or included in a species name, in parentheses, placed between the generic name and the specific epithet: e.g. the Tiger Cowry of the Indo-Pacific, Cypraea tigris Linnaeus, which...
, coining the name Regnosaurus Northamptoni. The generic name is derived from the Regni or Regnenses
Regnenses
The Regnenses, Regni or Regini were a British Celtic kingdom and later a civitas of Roman Britain. Their capital was Noviomagus Reginorum, known today as Chichester in modern West Sussex....
, a British tribe inhabiting Sussex
Sussex
Sussex , from the Old English Sūþsēaxe , is an historic county in South East England corresponding roughly in area to the ancient Kingdom of Sussex. It is bounded on the north by Surrey, east by Kent, south by the English Channel, and west by Hampshire, and is divided for local government into West...
. The specific name honours Spencer Compton, 2nd Marquess of Northampton
Spencer Compton, 2nd Marquess of Northampton
Spencer Joshua Alwyne Compton, 2nd Marquess of Northampton , known as Lord Compton from 1796 to 1812 and as Earl Compton from 1812 to 1828, was a British nobleman and patron of science and the arts....
, the president of the Royal Society, who was about to resign. By present conventions, the type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
is written as Regnosaurus northamptoni.
Regnosaurus is known only from the holotype
Holotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
BMNH 2422, a right mandibular (lower jaw) fragment, consisting of a third of the dentary and a part of the splenial
Splenial
The splenial is a small bone in the lower jaw of reptiles, amphibians and birds, usually located on the lingual side between the angular and suprangular....
. The specimen is six inches long and shows fifteen tooth sockets. Also some replacement teeth are visible. Other bone fragments have sometimes been referred to Regnosaurus, such as a fossil pubis
Pubis (bone)
In vertebrates, the pubic bone is the ventral and anterior of the three principal bones composing either half of the pelvis.It is covered by a layer of fat, which is covered by the mons pubis....
recovered on the Isle of Wight
Isle of Wight
The Isle of Wight is a county and the largest island of England, located in the English Channel, on average about 2–4 miles off the south coast of the county of Hampshire, separated from the mainland by a strait called the Solent...
, but as these are of other parts of the body and a reasonably complete skeleton is lacking, the identity cannot be proven. The same is true for some dermal spikes reported by William Blows. Regnosaurus was probably a rather small animal, about 4 metres (13 feet) long.
Phylogeny
First seen as some iguanodontid, Regnosaurus was later connected to armoured dinosaurs. In 1888 Richard LydekkerRichard Lydekker
Richard Lydekker was an English naturalist, geologist and writer of numerous books on natural history.-Biography:...
assigned it to the Scelidosauridae. In 1909 Friedrich von Huene
Friedrich von Huene
Friedrich von Huene was a German paleontologist who named more dinosaurs in the early 20th century than anyone else in Europe.-Biography:...
classified it in the stegosaurian Omosauridae and in 1911 Alfred von Zittel assigned it to the Stegosauridae
Stegosauridae
Stegosauridae is a family of stegosauria, large thyreophorans. They lived longer than other Stegosaurs; while all Huayangosauridae and most of basal stegosaurs died out in Tithonian - Kimmeridgian, stegosauridae survived till Middle Cretaceous. They are usually characterized by triangular plates on...
but these groups then had a different content and also included armoured forms. In 1956 Alfred Romer
Alfred Romer
Alfred Sherwood Romer was an American paleontologist and comparative anatomist and a specialist in vertebrate evolution.-Biography:...
synonymised it with Hylaeosaurus
Hylaeosaurus
Hylaeosaurus is the most obscure of the three animals used by Sir Richard Owen to first define the new group Dinosauria, in 1842. The original specimen, recovered by Gideon Mantell from the Tilgate Forest in the south of England in 1832, now resides in the Natural History Museum of London, where...
. An entirely different suggestion was made by John Ostrom
John Ostrom
John H. Ostrom was an American paleontologist who revolutionized modern understanding of dinosaurs in the 1960s, when he demonstrated that dinosaurs are more like big non-flying birds than they are like lizards , an idea first proposed by Thomas Henry Huxley in the 1860s, but which had garnered...
who surmised it might have been a sauropod.
The first to state that it was a stegosaurian in the modern sense was George Olshevsky
George Olshevsky
George Olshevsky is a freelance editor, writer, publisher, amateur paleontologist, and mathematician living in San Diego, California.Olshevsky maintains the comprehensive online Dinosaur Genera List...
in 1993. This was confirmed by Paul Barret and Paul Upchurch in 1995 who concluded that it is a stegosaur similar to Huayangosaurus
Huayangosaurus
Huayangosaurus is a genus of stegosaurian dinosaur from the Middle Jurassic of China. The name derives from "Huayang", an alternate name for Sichuan , and "saurus", meaning "lizard"...
, as the jaws are very similar. As the remains are so limited, many recent researchers have concluded Regnosaurus to be a nomen dubium
Nomen dubium
In zoological nomenclature, a nomen dubium is a scientific name that is of unknown or doubtful application...
.