Rapator

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Rapator
Temporal range: Albian-Cenomanian, 105–96  Ma
Rapator metacarpal.jpg
Holotype metacarpal
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Saurischia
Clade: Theropoda
Clade: Megaraptora
Genus: Rapator
von Huene, 1932
Type species
Rapator ornitholestoides
von Huene, 1932
Synonyms

Rapator is a genus of theropod dinosaur from the Griman Creek Formation of New South Wales, Australia, dating to the Albian-Cenomanian ages of the Cretaceous period, 105-96 million years ago. [1] It contains only the type species, Rapator ornitholestoides, which was originally named by Friedrich von Huene in 1932. [2]

Contents

Discovery

Skeletal diagram showing holotype hand bone in place Rapator Skeletal.svg
Skeletal diagram showing holotype hand bone in place

The holotype and only known specimen, BMNH R3718, consists of a single left hand bone, discovered around 1905 near Wollaston, on Lightning Ridge. [3] The fossil has been opalised. [3] The meaning of the generic name is problematic. Von Huene gave no etymology. [2] "Rapator" does not exist in Classical Latin and occurs only very rarely in Mediaeval Latin with the meaning "violator". [4] One possible explanation is that von Huene, having been influenced by Latin raptare, "to plunder", [5] mistakenly thought such a word actually existed with the meaning of "plunderer". [6] It has also been considered a simple misspelling of, or confusion with, raptor, "seizer" or "thief". [3] The specific name means "resembling Ornitholestes ". Remains of a megaraptorid, nicknamed "Lightning Claw," were discovered in opal fields southwest of Lightning Ridge, Australia, may well represent more material of Rapator. [7]

Description

Illustration of holotype manual bone Rapator.png
Illustration of holotype manual bone

The bone has a length of seven centimetres. [2] This manual element shows a prominent dorsomedial process, a feature shared with the much smaller Ornitholestes which occasioned the specific name. [3] The process with Ornitholestes is much less distinctive though. [3] On its upper end there is only one cotyle, from which von Huene deduced it must have been a metacarpal. [2] 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 (30 ft) has been estimated. [3]

Classification

Hypothetical life restoration as a megaraptoran RapatorCameronSpahn.jpg
Hypothetical life restoration as a megaraptoran

The type specimen of Rapator was originally described as a metacarpal I, a bone from the upper part of a theropod's hand. [2] It was later noted that the bone is similar to a finger bone, the first phalanx of the first finger, of an alvarezsaur [8] or of a primitive coelurosaurian similar to Nqwebasaurus . [9] 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. [10] However, White et al. found differences between the hand bone of Rapator and the equivalent bone of Australovenator, supporting the distinction between the two. They also noted that the two genera come from formations separated chronologically by at least 10 million years, making them unlikely to be synonymous. [1]

Rapator has been synonymised with Walgettosuchus , a theropod found in the same formation. [11] As the latter is only known from a caudal vertebra, the identity cannot be proven.

Related Research Articles

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Coelurosauria is the clade containing all theropod dinosaurs more closely related to birds than to carnosaurs.

<span class="mw-page-title-main">Tetanurae</span> Clade containing most theropod dinosaurs

Tetanurae is a clade that includes most theropod dinosaurs, including megalosauroids, allosauroids, tyrannosauroids, ornithomimosaurs, compsognathids and maniraptorans. Tetanurans are defined as all theropods more closely related to modern birds than to Ceratosaurus and contain the majority of predatory dinosaur diversity. Tetanurae likely diverged from its sister group, Ceratosauria, during the late Triassic. Tetanurae first appeared in the fossil record by the Early Jurassic about 190 mya and by the Middle Jurassic had become globally distributed.

Coelurus is a genus of coelurosaurian dinosaur from the Late Jurassic period. The name means "hollow tail", referring to its hollow tail vertebrae. Although its name is linked to one of the main divisions of theropods (Coelurosauria), it has historically been poorly understood, and sometimes confused with its better-known contemporary Ornitholestes. Like many dinosaurs studied in the early years of paleontology, it has had a confusing taxonomic history, with several species being named and later transferred to other genera or abandoned. Only one species is currently recognized as valid: the type species, C. fragilis, described by Othniel Charles Marsh in 1879. It is known from one partial skeleton found in the Morrison Formation of Wyoming, United States. It was a small bipedal carnivore with elongate legs.

<i>Afrovenator</i> Extinct genus of dinosaurs

Afrovenator is a genus of megalosaurid theropod dinosaur from the Middle or Late Jurassic Period on the Tiourarén Formation and maybe the Irhazer II Formation of the Niger Sahara region in northern Africa. Afrovenator represents the only properly identified Gondwanan megalosaur, with proposed material of the group present in the Late Jurassic on Tacuarembó Formation of Uruguay and the Tendaguru Formation of Tanzania.

<i>Metriacanthosaurus</i> Metriacanthosaurid theropod dinosaur genus from Middle Jurassic period

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<i>Altispinax</i> Genus of reptiles (fossil)

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<i>Megaraptor</i> Extinct genus of dinosaurs

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<i>Walgettosuchus</i> Extinct genus of dinosaurs

Walgettosuchus is a dubious or possibly invalid genus of extinct tetanuran theropod dinosaur that lived in Australia during the Late Cretaceous (Cenomanian). It is known from a single caudal vertebra.

<i>Valdoraptor</i> Extinct genus of dinosaurs

Valdoraptor is a genus of theropod dinosaur from the Early Cretaceous. Its fossils were found in England. It is known only from bones of the feet. The holotype, BMNH R2559, was found near Cuckfield in layers of the Tunbridge Wells Sand Formation dating from the late Valanginian. The specimen is damaged lacking parts of the upper and lower ends. It has a conserved length of 215 millimetres (8.5 in) and an estimated length of 240 millimetres (9.4 in). This genus is paleontologically significant for being the first ornithomimosaur specimen known from England and represents the earliest record of ornithomimosaurs.

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<i>Australovenator</i> Extinct genus of dinosaurs

Australovenator is a genus of megaraptoran theropod dinosaur from Cenomanian -age Winton Formation of Australia. It is known from partial cranial and postcranial remains which were described in 2009 by Scott Hocknull and colleagues, although additional descriptions and analyses continue to be published. It is the most complete predatory dinosaur discovered in Australia. It has been suggested that Australovenator is a sister taxon to Fukuiraptor, although some phylogenetic analyses find it to be a more derived member of the Megaraptora, possibly being part of the main Megaraptoridae family itself.

<span class="mw-page-title-main">Neovenatoridae</span> Extinct family of dinosaurs

Neovenatoridae is a proposed clade of carcharodontosaurian dinosaurs uniting some primitive members of the group such as Neovenator with the Megaraptora, a group of theropods with controversial affinities. Other studies recover megaraptorans as basal coelurosaurs unrelated to carcharodontosaurs. Other theropods with uncertain affinities such as Gualicho, Chilantaisaurus and Deltadromeus are also sometimes included.

<span class="mw-page-title-main">Megaraptora</span> Extinct clade of dinosaurs

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References

  1. 1 2 White, M. A.; Falkingham, P. L.; Cook, A. G.; Hocknull, S. A.; Elliott, D. A. (2013). "Morphological comparisons of metacarpal I forAustralovenator wintonensisandRapator ornitholestoides: Implications for their taxonomic relationships". Alcheringa: An Australasian Journal of Palaeontology. 37 (4): 435–441. doi:10.1080/03115518.2013.770221. S2CID   82672110.
  2. 1 2 3 4 5 Huene, F. von. (1932). Die fossile Reptil-Ordnung Saurischia, ihre Entwicklung und Geschichte. Monogr. Geol. Pal. 4 (1) pts. 1 and 2, viii + 361 pp.
  3. 1 2 3 4 5 6 Long, J.A. (1998). Dinosaurs of Australia and New Zealand and Other Animals of the Mesozoic Era, Harvard University Press, p. 104
  4. Tombeur, Paul. (1998) Thesaurus formarum totius Latinitatis a Plauto usque ad saeculum XXum : TF. CETEDOC, Universitas Catholica Lovaniensis, Lovanii Novi
  5. https://web.archive.org/web/20100920040121/http://dinosauria.com/dml/names/dinor.htm Dinosauria Translation and Pronunciation Guide, retrieved 28-09-2010
  6. Lambert, D. (1991) The Dinosaur Data Book: the definitive illustrated encyclopedia of dinosaurs and other prehistoric reptiles. Gramercy Books. p. 89
  7. Bell, P. R., Cau, A., Fanti, F., & Smith, E. (2015). A large-clawed theropod (Dinosauria: Tetanurae) from the Lower Cretaceous of Australia and the Gondwanan origin of megaraptorid theropods. Gondwana Research .
  8. Holtz, Molnar, and Currie (2004). "Basal Tetanurae." In Weishampel, Dodson and Osmolska (eds.), The Dinosauria Second Edition. University of California Press. 861 pp.
  9. Salisbury, Agnolin, Ezcurra, and Pias (2007). "A critical reassessment of the Cretaceous non-avian dinosaur faunas of Australia and New Zealand." Journal of Vertebrate Paleontology, 27(3): 138A.
  10. Agnolin, Ezcurra, Pais and Salisbury, (2010). "A reappraisal of the Cretaceous non-avian dinosaur faunas from Australia and New Zealand: Evidence for their Gondwanan affinities." Journal of Systematic Palaeontology, 8(2): 257-300.
  11. Steel, R. (1970) Handbuch der Paläoherpetologie/Encyclopedia of Paleoherpetology. Part 14. Saurischia. Gustav Fischer Verlag, Stuttgart 1-87