Fukuiraptor Temporal range: Early Cretaceous, | |
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Reconstructed skeleton | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Clade: | Dinosauria |
Clade: | Saurischia |
Clade: | Theropoda |
Clade: | † Megaraptora |
Genus: | † Fukuiraptor Azuma & Currie, 2000 |
Type species | |
†Fukuiraptor kitadaniensis Azuma & Currie, 2000 |
Fukuiraptor ("thief of Fukui") was a medium-sized megaraptoran theropod dinosaur of the Early Cretaceous epoch (either Barremian or Aptian) that lived in what is now Japan. [1] Fukuiraptor is known from the Kitadani Formation [2] and possibly also the Sebayashi Formation. [3]
The type specimen is a partial skeleton (designated FPDM-V97122) discovered in the Kitadani quarry near Katsuyama in the Fukui prefecture. It is thought that this specimen was not mature and an adult may have been larger. The remains of many other individuals have been found in the quarry, with numerous humeri, femurs, and teeth being assigned to this species. [2] However, the other individuals recovered from the same locality are mostly juveniles that were smaller than the holotype (Currie & Azuma, 2006), in the smallest case less than a quarter of the holotype's size. A tooth (NDC-P0001) discovered in a block of conglomerate from the Sebayashi Formation has been referred to Fukuiraptor as well. [4]
As indicated by its slender phalanges, Fukuiraptor was a relatively lightly built animal, regardless of its maturity. [1] The immature holotype is estimated to reach 4.2 metres (14 ft) long and weigh 175 kg (386 lb) in its initial description. [1] In 2010 Gregory Paul gave a length of 5 meters (16 ft) and a weight of 300 kg (660 lbs). [5] In 2014, its body mass was estimated up to 250 kilograms (550 lb). [6] Molina-Pérez and Larramendi estimated a length of 4.3 meters (14.1 ft) and a weight of 590 kg (1,300 lbs) in 2016. [7]
The distinctive teeth of Fukuiraptor show similarities with both carcharodontosaurids (being very compressed and blade-like, as well as having wrinkled enamel) and tyrannosaurids (having oblique blood grooves near the serrations). [2] The holotype also had very large and flat manual unguals (hand claws), which played a role in its initial classification as a dromaeosaurid (as the hand claws were mistaken for foot claws) as well as its current classification as a megaraptoran. [8]
Initially considered a member of the Dromaeosauridae when first discovered, its initial describers considered it a carnosaur, related to Allosaurus . More recent studies consider it a megaraptoran, an enigmatic group which may have been part of the family Neovenatoridae. [8] However, more recently, another analysis has proposed that all megaraptorans are actually tyrannosauroids, which would reclassify Fukuiraptor as a tyrannosauroid coelurosaur. [9] Recent cladistic analysis of the theropod Gualicho has suggested that Fukuiraptor and other megaraptorans are either allosauroids, or non-tyrannosauroid basal coelurosaurs. [10]
It has been suggested that Fukuiraptor is a close relative to the Australian megaraptoran known as Australovenator , [11] however a subsequent study has placed Australovenator as a megaraptorid megaraptoran alongside other derived South American taxa, while Fukuiraptor remains a megaraptoran outside of Megaraptoridae. [12]
Below is a cladogram reconstructing the position of Fukuiraptor in the Megaraptora as per Delcourt and Grillo, 2018. [12]
Megaraptora |
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In the Kitadani Formation, where fossils of Fukuiraptor have been recovered, [1] fossils of other vertebrates have been preserved. Among the species that have been properly described and named are Fukuisaurus tetoriensis , [13] a styracostern ornithischian, Fukuititan nipponensis , [14] a titanosauriform sauropod, Koshisaurus katsuyama , [15] a hadrosauroid ornithischian, Fukuivenator paradoxus , [16] a therizinosaurian theropod, and Fukuipteryx prima , [17] an avialan as defined by the authors.
Carnosauria is an extinct group of carnivorous theropod dinosaurs that lived during the Jurassic and Cretaceous periods.
Deltadromeus is a genus of theropod dinosaur from the Aoufous Formation of Morocco.
Megaraptor is a genus of large theropod dinosaur that lived in the ages of the Late Cretaceous. Its fossils have been discovered in the Patagonian Portezuelo Formation of Argentina, South America. Initially thought to have been a giant dromaeosaur-like coelurosaur, it was classified as a neovenatorid allosauroid in previous phylogenies, but more recent phylogeny and discoveries of related megaraptoran genera has placed it as either a basal tyrannosauroid or a basal coelurosaur with some studies still considering it a neovenatorid.
Orkoraptor is a genus of medium-sized megaraptoran theropod dinosaur from the late Cretaceous Period of Argentina. It is known from incomplete fossil remains including parts of the skull, teeth, tail vertebrae, and a partial tibia. The specialized teeth resemble those of some maniraptoriform theropods, namely the deinonychosaurs and compsognathids. This and other anatomical features led the authors who described it to suggest that it was a maniraptoran coelurosaur. However, subsequent studies found it to be a megaraptoran. Found in the Cerro Fortaleza Formation of Southern Patagonia, it is one of the southernmost carnivorous dinosaurs known from South America.
The Fukui Prefectural Dinosaur Museum, located in Katsuyama, Fukui, Japan, is one of the leading dinosaur museums in Asia that is renowned for its exhibits of fossil specimens of dinosaurs and paleontological research. It is sited in the Nagaoyama Park near the Kitadani Dinosaur Quarry that the Lower Cretaceous Kitadani Formation of the Tetori Group is cropped out and a large number of dinosaur remains including Fukuiraptor kitadaniensis and Fukuisaurus tetoriensis are found and excavated.
Aerosteon is a genus of megaraptoran dinosaur from the Late Cretaceous period of Argentina. Its remains were discovered in 1996 in the Anacleto Formation, which is from the late Campanian. The type and only known species is A. riocoloradensis. Its specific name indicates that its remains were found 1 km north of the Río Colorado, in Mendoza Province, Argentina.
The Kitadani Formation is a unit of Lower Cretaceous sedimentary rock which crops out near the city of Katsuyama in Fukui Prefecture, Japan, and it is the primary source of Cretaceous-aged non-marine vertebrate fossils in Japan. Dinosaur remains are among the fossils that have been recovered from the formation, but it also preserves a diverse assemblage of plants, invertebrates, and other vertebrates. Most, if not all, of the fossil specimens collected from the Kitadani Formation are reposited at the Fukui Prefectural Dinosaur Museum.
Australovenator is a genus of megaraptoran theropod dinosaur from Cenomanian -age Winton Formation of Australia. Some specimens from the Albian-aged Eumeralla Formation may belong to Australovenator. 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.
Megaraptora is a clade of carnivorous theropod dinosaurs with controversial relationships to other tetanuran theropods. Its derived members, the Megaraptoridae are noted for their large hand claws and powerfully-built forelimbs, which are usually reduced in size in other large theropods.
Fukuititan is a genus of sauropod dinosaur that lived in the Early Cretaceous in what is now Japan. The genus contains a single species, Fukuititan nipponensis. It is known from FPDM-V8468, the associated partial skeleton of a single individual, recovered from the Kitadani Dinosaur Quarry of the Tetori Group, at Katsuyama City. The type species, Fukuititan nipponensis, was described in 2010 by Japanese scientists Yoichi Azuma and Masateru Shibata of the Fukui Prefectural Dinosaur Museum. The discovery sheds light on Japanese titanosauriforms, which are poorly known in the region.
The Khok Kruat Formation is a rock formation found in northeastern Thailand. It is the uppermost formation of the Khorat Group. It is dated to the Aptian stage of the Early Cretaceous period, and is notable for its fossils of dinosaurs. It is equivalent to the Gres superieurs Formation of Laos. The group is a fluvial formation consisting primarily of red siltstones and sandstones.
Siats (/see-ats/) is an extinct genus of large theropod dinosaur known from the Late Cretaceous Cedar Mountain Formation of Utah, United States. It contains a single species, Siats meekerorum. It was initially classified as a megaraptoran, a clade of large theropods with very controversial relationships. Siats may be a neovenatorid allosauroid, a coelurosaur of uncertain phylogenetic position, or a tyrannosauroid.
Koshisaurus is a monospecific genus of basal hadrosauroid from the Kitadani Formation in Japan. The discovery of the genus suggests that hadrosauroids had higher diversity along the eastern margin of Asia in the Early Cretaceous. "Koshi" means an old Japanese regional name including Fukui prefecture where fossils of the genus were discovered.
Fukuivenator is an extinct genus of maniraptoran theropod dinosaur from the Early Cretaceous of Japan.
Plagioolithus is an oogenus of fossil egg. It is from the Early Cretaceous of Japan. It was probably laid by a bird, making it the oldest known fossil bird egg.
Murusraptor is a genus of carnivorous megaraptoran theropod dinosaur from the Sierra Barrosa Formation, part of the Neuquén Group of Patagonia, in Argentina, South America. It is known from a single specimen that consists of a partial skull, ribs, partial pelvis, leg and other assorted skeletal elements.
Symmetrolestes is an extinct genus of small spalacotheriid mammal from the Early Cretaceous period of Japan. The genus contains one species known as S. parvus, the type fossil is from fluvial deposits located in the Dinosaur Quarry in the Kitadani Formation, near the city of Katsuyama which lies alongside valley of the Sugiyamagawa River. It was described by Tsubamoto and Rougier in 2004 keeping the holotype at the National Science Museum, Tokyo, Japan.
Fukuipteryx is an extinct genus of basal avialan dinosaurs found in Early Cretaceous deposits from Japan's Kitadani Formation. It contains one species, Fukuipteryx prima.
Tyrannomimus is an extinct genus of ornithomimosaurian theropod dinosaurs from the Kitadani Formation of Japan. The type species is Tyrannomimus fukuiensis.