Rapator
Encyclopedia
Rapator is a genus
of theropod dinosaur
from the early Cretaceous
period (Aptian
age) Griman Creek Formation
of New South Wales
, Australia
.
The type species
, Rapator ornitholestoides, was originally named by Friedrich von Huene
in 1932. The meaning of the generic name is problematic. Von Huene gave no etymology
, explanation as to the derivation of the word. "Rapator" does not exist in Classical Latin
and occurs only very rarely in Mediaeval Latin with the meaning "violator". One possible explanation is that von Huene, having been influenced by Latin
raptare, "to plunder", mistakenly thought such a word actually existed with the meaning of "plunderer". It has also been considered a simple misspelling of, or confusion with, raptor, "seizer" or "thief". The specific name means "resembling Ornitholestes
".
The holotype
, BMNH R3718, consists of a single left hand bone, discovered around 1905 near Wollaston
, on the Lightning Ridge. The fossil has been opalised
. Originally thought to be a metacarpal I, a bone from the upper part of an indeterminate theropod hand, it was later noted that the bone is similar to a finger bone, the first phalanx
of the first finger, of an alvarezsaur
or of a primitive coelurosauria
n similar to Nqwebasaurus
. With the discovery of Australovenator
, which had a similar metacarpal, Rapator was recognized as a probable megaraptoran. In fact, Australovenator and Rapator differ only in some small details of the bone and may be synonyms, though Agnolin and colleagues in 2010 considered Rapator a dubious genus (nomen dubium
) due to its fragmentary nature. Earlier, Rapator had been synonymised with Walgettosuchus
, a theropod found in the same formation. As the latter is only known from a caudal vertebra however, the identity cannot be proven.
The bone has a length of seven centimetres. This manual element shows a prominent dorsomedial process, a feature shared with the much smaller Ornitholestes which occasioned the specific name. The process with Ornitholestes is much less distinctive though. On its upper end there is only one cotyle, from which von Huene deduced it must have been a metacarpal. However, several coelurosaurian groups lack a second cotyle on the first phalanx also. If Rapator had a build like Australovenator, it would have attained a considerable size: a body length of nine metres has been estimated.
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 theropod 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...
from 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 (Aptian
Aptian
The Aptian is an age in the geologic timescale or a stage in the stratigraphic column. It is a subdivision of the Early or Lower Cretaceous epoch or series and encompasses the time from 125.0 ± 1.0 Ma to 112.0 ± 1.0 Ma , approximately...
age) Griman Creek Formation
Griman Creek Formation
The Griman Creek Formation is a geological formation in New South Wales, Australia whose strata date back to the Early Cretaceous. Dinosaur remains are among the fossils that have been recovered from the formation.-Vertebrate paleofauna:...
of New South Wales
New South Wales
New South Wales is a state of :Australia, located in the east of the country. It is bordered by Queensland, Victoria and South Australia to the north, south and west respectively. To the east, the state is bordered by the Tasman Sea, which forms part of the Pacific Ocean. New South Wales...
, Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
.
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...
, Rapator ornitholestoides, was originally named by 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:...
in 1932. The meaning of the generic name is problematic. Von Huene gave no etymology
Etymology
Etymology is the study of the history of words, their origins, and how their form and meaning have changed over time.For languages with a long written history, etymologists make use of texts in these languages and texts about the languages to gather knowledge about how words were used during...
, explanation as to the derivation of the word. "Rapator" does not exist in Classical Latin
Classical Latin
Classical Latin in simplest terms is the socio-linguistic register of the Latin language regarded by the enfranchised and empowered populations of the late Roman republic and the Roman empire as good Latin. Most writers during this time made use of it...
and occurs only very rarely in Mediaeval Latin with the meaning "violator". One possible explanation is that von Huene, having been influenced by Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
raptare, "to plunder", mistakenly thought such a word actually existed with the meaning of "plunderer". It has also been considered a simple misspelling of, or confusion with, raptor, "seizer" or "thief". The specific name means "resembling Ornitholestes
Ornitholestes
Ornitholestes was a small theropod dinosaur of the late Jurassic of Western Laurasia . To date, it is known only from a single partial skeleton, and badly crushed skull found at the Bone Cabin Quarry near Medicine Bow, Wyoming, in 1900...
".
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 R3718, consists of a single left hand bone, discovered around 1905 near Wollaston
Wollaston
-Places:Australia* John Wollaston Anglican Community School, private school in Kelmscott, Perth, Western Australia* Wollaston, Western Australia, suburb of Bunbury, Western AustraliaCanada* Wollaston Islands...
, on the Lightning Ridge. The fossil has been opalised
Opal
Opal is an amorphous form of silica related to quartz, a mineraloid form, not a mineral. 3% to 21% of the total weight is water, but the content is usually between 6% to 10%. It is deposited at a relatively low temperature and may occur in the fissures of almost any kind of rock, being most...
. Originally thought to be a metacarpal I, a bone from the upper part of an indeterminate theropod hand, it was later noted that the bone is similar to a finger bone, the first phalanx
Phalanx bones
In anatomy, phalanx bones are those that form the fingers and toes. In primates such as humans and monkeys, the thumb and big toe have two phalanges, while the other fingers and toes consist of three. Phalanges are classified as long bones.The phalanges do not have individual names...
of the first finger, of an alvarezsaur
Alvarezsauridae
Alvarezsauridae is an enigmatic family of small, long-legged running dinosaurs. Although originally thought to represent the earliest known flightless birds, a consensus of recent work suggests that they are primitive members of the Maniraptora. Other work found them to be the sister group to the...
or of a primitive coelurosauria
Coelurosauria
Coelurosauria is the clade containing all theropod dinosaurs more closely related to birds than to carnosaurs. In the past, it was used to refer to all small theropods, although this classification has been abolished...
n similar to Nqwebasaurus
Nqwebasaurus
Nqwebasaurus is the name given to a genus of dinosaur from the Tithonian to Valanginian . It was a basal coelurosaur related to Ornitholestes. Its fossils were found in South Africa in the Kirkwood Formation, which is called Nqweba in the native language of the Xhosa...
. With the discovery of Australovenator
Australovenator
Australovenator is a genus of allosauroid theropod dinosaur from late Albian -age rocks of Australia...
, which had a similar metacarpal, Rapator was recognized as a probable megaraptoran. In fact, Australovenator and Rapator differ only in some small details of the bone and may be synonyms, though Agnolin and colleagues in 2010 considered Rapator a dubious genus (nomen dubium
Nomen dubium
In zoological nomenclature, a nomen dubium is a scientific name that is of unknown or doubtful application...
) due to its fragmentary nature. Earlier, Rapator had been synonymised with Walgettosuchus
Walgettosuchus
Walgettosuchus is a dubious genus of theropod dinosaur.In 1905 an opalised vertebra of a theropod dinosaur was found near Wollaston, at Lightning Ridge in New South Wales...
, a theropod found in the same formation. As the latter is only known from a caudal vertebra however, the identity cannot be proven.
The bone has a length of seven centimetres. This manual element shows a prominent dorsomedial process, a feature shared with the much smaller Ornitholestes which occasioned the specific name. The process with Ornitholestes is much less distinctive though. On its upper end there is only one cotyle, from which von Huene deduced it must have been a metacarpal. However, several coelurosaurian groups lack a second cotyle on the first phalanx also. If Rapator had a build like Australovenator, it would have attained a considerable size: a body length of nine metres has been estimated.