| Hexing Temporal range: Early Cretaceous, | |
|---|---|
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Clade: | Dinosauria |
| Clade: | Saurischia |
| Clade: | Theropoda |
| Clade: | † Ornithomimosauria |
| Genus: | † Hexing Jin, Chen & Godefroit, 2012 |
| Type species | |
| †Hexing qingyi Jin, Chen & Godefroit, 2012 | |
Hexing is an extinct genus of basal ornithomimosaur dinosaur known from the Early Cretaceous of northeastern China. It contains a single species, Hexing qingyi.
In the early twenty-first century, a local farmer at Xiaobeigou in Liaoning discovered the skeleton of a small theropod. He prepared the fossil himself, trying to enhance its value by restoring damaged bones and adding fake parts. Eventually the specimen was obtained by the Geological Museum of Jilin University and more expertly prepared, during which process the added parts were again removed. [1]
In 2012, the type species Hexing qingyi was named and described by Jin Liyong, Chen Jun and Pascal Godefroit. The generic name means "like a crane" in Chinese. The specific name means "with slender wings". [1]
The holotype, JLUM-JZ07b1, was found in fluvial deposits of the lower Yixian Formation, which have a highest possible age of 139 million years and a lowest of 128 million years and thus date from some time in the early Valanginian to early Barremian stage. It consists of a partial skeleton, containing the skull, the lower jaws, a series of five cervical vertebrae, the shoulder girdle and the majority of both forelimbs and hindlimbs. The remains have not been well preserved. The specimen represents a subadult or adult individual. [1]
The holotype specimen consists of the remains of a small individual. Because most of the vertebral column is absent, its body length cannot be directly determined, but a comparison can be made with the previously smallest known ornithomimosaur, the 1.6 metres long Shenzhousaurus , which has a thighbone length of 191 millimetres, while the femur length of Hexing is 135 millimetres. Such a small body size was among ornithomimosaurs up till now only known from juveniles but the holotype is not a young animal as is shown by the complete fusion of the skull bones, the neck ribs, the scapulocoracoid and the ankle bones. [1]
The describers determined some autapomorphies of Hexing, its unique derived traits. The snout tip reaches downwards in front of the lower jaws, so deeply that the roof of the mouth at this point is at a level with the bottom edge of the lower jaw. The fossa antorbitalis, a depression on the side of the maxilla, covers almost the entire outer surface of that bone. The parietal bones are joint at their midline in a crest. The large bone extensions at the back of the skull, the processus paroccipitales, are hanging down below the level of the foramen magnum. In the lower jaw, the dentary has an opening in its side. The formula for the phalanges of the hand is 1-2-3-0-0 or 2-3-3-0-0 — or 0-1-2-3-0/0-2-2-3-0 if the three fingers of the hand are interpreted as the second, third and fourth. The upper phalanges of the second and third (or third and fourth) finger are elongated with more than 75% of the length of the corresponding metacarpal. The lower leg is relatively long with the tibiotarsus having 137% of the length of the thighbone. [1]
The skull of Hexing is relatively large with a length of 136 millimetres. It is elongated and triangular in side view. The snout is appending with a slight kink above the middle of the fossa antorbitalis, which at this point is reinforced by a distinctive vertical bone strut, a pila interfenestralis dividing the depression in two halves: at its rear an oval skull opening, the fenestra antorbitalis, pierces the surface and at its front the uniquely large and deep hollowing out of the maxilla side is visible, in which another opening, the fenestra maxillaris, might have been present, though this is uncertain because of damage. The front of the snout consists of a small praemaxilla, continuing the line of the nasals downwards and forming a small upper beak in front of the lower jaws. The beak is separated by a low notch from the lower maxilla edge, which is toothless. [1]
The front of the lower jaw is low and slightly upward curving. In the left dentary the remains of three or four low conical teeth are visible; of these damage obscures most detail. The dentary has a small opening in the side surface. The higher back of the lower jaw seems to show a much larger opening, but this is an artefact caused by the original inexpert preparation damaging the thin bone surface of an extensive mandibular fossa. A real and much smaller external mandibular fenestra is present in front of this. Neither the lower jaw nor the upper jaw form cutting edges. [1]
The cervical vertebrae are elongated with low spines. They are pneumatised and have large triangular diapophyses and postzygapophyses. [1]
The shoulder blade is elongated and narrow, without expanded upper end. The humerus is somewhat shorter than the shoulder blade and is slender. Its shaft is not twisted. The bones of the lower arm are likewise elegant and straight. A large part of the over ten centimetres long hand has been preserved; this shows a configuration that is fundamentally different from that of related species. The describers have carefully checked whether this could have been caused by falsifications during the original preparation but could find no sign of any tampering. As a result, the identification of the respective parts is highly problematical. As preserved the hand shows three rows of elements: the first with two bones and the second and third with four bones. If these would represent both phalanges and metacarpals, these series should have three, four and five elements, however: from the first and third row a bone is missing. The authors considered it most likely that in the first finger the upper phalanx was completely reduced, that is: naturally absent. However, as this would imply that the claw attached directly to the metacarpal and this metacarpal would then be exceptionally long, they allowed for the alternative possibility that the visible element was the first phalanx and that the metacarpal was lacking because of an incompleteness of the fossil. In the third finger the number of phalanges seemed almost certainly reduced from four to three because the place of the two normal short upper phalanges is taken by a single long element. The description of this situation is complicated by the fact that the describers follow the hypothesis of Xu Xing that with Tetanurae — including birds and Hexing — the first, second and third fingers are actually the second, third and fourth. This would in the standard terminology make the formula of the phalanges 1-3-3-0-0 or alternatively 2-3-3-0-0 and following the hypothesis of Xu 0-1-3-3-0 or 0-2-3-3-0. In general the phalanges are slender and elongated. The hand claws are relatively large and curved, with a flatter underside. [1]
The thighbone is strongly curved, with a convex anterior end. The tibia is 185 millimetres long and thus very elongated compared with the femur; only some juvenile ornithomimid specimens have relatively longer tibiotarsi. The first metatarsal is half as long as the second, the longest of the foot. The foot claws are flatter than the hand claws. [1]
The describers assigned Hexing a basal position in the Ornithomimosauria. Their phylogenetic analysis found Hexing to be more derived than Pelecanimimus , but less derived than a clade consisting of Beishanlong , Harpymimus , Garudimimus and the Ornithomimidae. Shenzhousaurus , also from the Yixian Formation, was found in a polytomy with Hexing and this clade, as shown by the following cladogram: [1]
| Ornithomimosauria |
| ||||||||||||||||||||||||||||||
The small forms Hexing and Senzhousaurus are the oldest known ornithomimosaurians, as Pelecanimimus dates from the late Barremian. Because this latter species is more basal, the authors considered this a strong indication that a land bridge had formed between Europe and Asia long before the Aptian, the normally assumed date for this event. [1]
Lesothosaurus is a monospecific genus of ornithischian dinosaur that lived during the Early Jurassic in what is now South Africa and Lesotho. It was named by paleontologist Peter Galton in 1978, the name meaning "lizard from Lesotho". The genus has only one valid species, Lesothosaurus diagnosticus. Lesothosaurus is one of the most completely-known early ornithischians, based on numerous skull and postcranial fossils from the Upper Elliot Formation. It had a simpler tooth and jaw anatomy than later ornithischians, and may have been omnivorous in some parts of the year.
Harpymimus is a basal ornithomimosaurian theropod dinosaur from the Early Cretaceous Period of what is now Mongolia. Unlike later, more derived ornithomimosaurs, Harpymimus still possessed teeth, although they appear to have been restricted to the dentary of the lower jaw.
Pelecanimimus is an extinct genus of basal ("primitive") ornithomimosaurian dinosaur from the Early Cretaceous of Spain. It is notable for possessing more teeth than any other member of the Ornithomimosauria, most of which were toothless.
Iguanodontidae is a family of iguanodontians belonging to Styracosterna, a derived clade within Ankylopollexia.
Sinovenator is a genus of troodontid dinosaur from China. It is from the early Cretaceous Period.
Sinusonasus is a genus of dinosaurs from the Early Cretaceous Period, recovered from the Yixian Formation. It lived in what is now the Liaoning Province of China. Sinusonasus was a theropod, specifically a troodontid dinosaur.
Jeholosaurus is a genus of neornithischian dinosaur from the Early Cretaceous Period. It is thought to have been a herbivorous small ornithopod.
Askeptosaurus is an extinct genus of askeptosauroid, a marine reptile from the extinct order Thalattosauria. Askeptosaurus is known from several well-preserved fossils found in Middle Triassic marine strata in what is now Italy and Switzerland.
Chimaerasuchus is an extinct genus of Chinese crocodyliform from the Early Cretaceous Wulong Formation. The four teeth in the very tip of its short snout gave it a "bucktoothed" appearance. Due its multicusped teeth and marked heterodonty, it is believed to have been an herbivore. Chimaerasuchus was originally discovered in the 1960s but not identified as a crocodyliform until 1995, instead thought to possibly be a multituberculate mammal. It is highly unusual, as only two other crocodyliforms have displayed any characteristics resembling its adaptations to herbivory.
Sinocalliopteryx is a genus of carnivorous compsognathid theropod dinosaurs from the Lower Cretaceous Yixian Formation of China.
Anatosuchus is an extinct genus of notosuchian crocodylomorph discovered in Gadoufaoua, Niger, and described by a team of palaeontologists led by the American Paul Sereno in 2003, in the Journal of Vertebrate Paleontology. Its duck-like snout coincidentally makes it resemble a crocoduck, an imagined hybrid animal with the head of a crocodile and the body of a duck.
Adamantinasuchus is an extinct genus of notosuchian crocodylomorph from and named after the Late Cretaceous Adamantina Formation of Brazil. It is known from only one fossil, holotype UFRJ-DG 107-R, collected by William Nava. The fossil consists of a partial skull, fragmentary limb bones and a few broken vertebrae, and was found 25 kilometres (16 mi) southwest of the town of Marilia, near a reservoir dam. Adamantinasuchus was approximately 60 centimetres (24 in) long from nose to tail, and would have only weighed a few kilograms.
Vancleavea is a genus of extinct, armoured, non-archosaurian archosauriforms from the Late Triassic of western North America. The type and only known species is V. campi, named by Robert Long & Phillip A Murry in 1995. At that time, the genus was only known from fragmentary bones including osteoderms and vertebrae. However, since then many more fossils have been found, including a pair of nearly complete skeletons discovered in 2002. These finds have shown that members of the genus were bizarre semiaquatic reptiles. Vancleavea individuals had short snouts with large, fang-like teeth, and long bodies with small limbs. They were completely covered with bony plates known as osteoderms, which came in several different varieties distributed around the body. Phylogenetic analyses by professional paleontologists have shown that Vancleavea was an archosauriform, part of the lineage of reptiles that would lead to archosaurs such as dinosaurs and crocodilians. Vancleavea lacks certain traits which are present in most other archosauriforms, most notably the antorbital, mandibular and supratemporal fenestrae, which are weight-saving holes in the skulls of other taxa. However, other features clearly support its archosauriform identity, including a lack of intercentra, the presence of osteoderms, an ossified laterosphenoid, and several adaptations of the femur and ankle bones. In 2016, a new genus of archosauriform, Litorosuchus, was described. This genus resembled both Vancleavea and more typical archosauriforms in different respects, allowing Litorosuchus to act as a transitional fossil linking Vancleavea to less aberrant archosauriforms.
Xixiasaurus is a genus of troodontid dinosaur that lived during the Late Cretaceous Period in what is now China. The only known specimen was discovered in Xixia County, Henan Province, in central China, and became the holotype of the new genus and species Xixiasaurus henanensis in 2010. The names refer to the areas of discovery, and can be translated as "Henan Xixia lizard". The specimen consists of an almost complete skull, part of the lower jaw, and teeth, as well as a partial right forelimb.
This glossary explains technical terms commonly employed in the description of dinosaur body fossils. Besides dinosaur-specific terms, it covers terms with wider usage, when these are of central importance in the study of dinosaurs or when their discussion in the context of dinosaurs is beneficial. The glossary does not cover ichnological and bone histological terms, nor does it cover measurements.
Panguraptor is a genus of coelophysid theropod dinosaur known from fossils discovered in Lower Jurassic rocks of southern China. The type and only known species is Panguraptor lufengensis. The generic name refers to the deity Pangu but also to the supercontinent Pangaea for which in a geological context the same characters are used: 盘古. Raptor means "seizer", "robber" in Latin. The specific name is a reference to the Lufeng Formation. The holotype specimen was recovered on 12 October 2007 from the Lufeng Formation of Yunnan, which is noted for sauropodomorph fossils. It was described in 2014 by You Hai-Lu and colleagues.
Jianianhualong is a genus of troodontid theropod dinosaur from the Early Cretaceous of China. It contains a single species, Jianianhualong tengi, named in 2017 by Xu Xing and colleagues based on an articulated skeleton preserving feathers. The feathers at the middle of the tail of Jianianhualong are asymmetric, being the first record of asymmetrical feathers among the troodontids. Despite aerodynamic differences from the flight feathers of modern birds, the feathers in the tail vane of Jianianhualong could have functioned in drag reduction whilst the animal was moving. The discovery of Jianianhualong supports the notion that asymmetrical feathers appeared early in the evolutionary history of the Paraves.
Daliansaurus is a genus of small troodontid theropod dinosaur, measuring approximately 1 metre long, from the Early Cretaceous of China. It contains a single species, D. liaoningensis, named in 2017 by Shen and colleagues from a nearly complete skeleton preserved in three dimensions. Daliansaurus is unusual in possessing an enlarged claw on the fourth digit of the foot, in addition to the "sickle claw" found on the second digit of the feet of most paravians. It also has long metatarsal bones, and apparently possesses bird-like uncinate processes. In the Lujiatun Beds of the Yixian Formation, a volcanically-influenced region with a cold climate, Daliansaurus lived alongside its closest relatives - Sinovenator, Sinusonasus, and Mei, with which it forms the group Sinovenatorinae.
Liaoningvenator is a genus of troodontid theropod dinosaur from the Early Cretaceous of China. It contains a single species, L. curriei, named after paleontologist Phillip J. Currie in 2017 by Shen Cai-Zhi and colleagues from an articulated, nearly complete skeleton, one of the most complete troodontid specimens known. Shen and colleagues found indicative traits that placed Liaoningvenator within the Troodontidae. These traits included its numerous, small, and closely packed teeth, as well as the vertebrae towards the end of its tail having shallow grooves in place of neural spines on their top surfaces.
Caihong is a genus of small paravian theropod dinosaur from China that lived during the Late Jurassic period.
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
