Asiatyrannus

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Asiatyrannus
Temporal range: Late Cretaceous (Maastrichtian), ~66.7 Ma [1]
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Asiatyrannus (holotype).png
Skeletal diagram and fossil elements of the Asiatyrannus holotype
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Saurischia
Clade: Theropoda
Family: Tyrannosauridae
Subfamily: Tyrannosaurinae
Genus: Asiatyrannus
Zheng et al., 2024
Species:
A. xui
Binomial name
Asiatyrannus xui
Zheng et al., 2024

Asiatyrannus (meaning "Asian tyrant") is an extinct genus of tyrannosaurine theropod dinosaurs from the Late Cretaceous Nanxiong Formation of China. The genus contains a single species, A. xui, known from a single specimen consisting of a skull and partial postcranial skeleton. Asiatyrannus is notable for its deep-snouted skull and small body size, in contrast to the gracile snout and larger size of the contemporary Qianzhousaurus . It represents the southernmost record of an Asian tyrannosaurid. [2]

Contents

Discovery and naming

The Asiatyrannus holotype specimen, ZMNH M30360, was discovered in September 2017 in sediments of the Nanxiong Formation near Shahe Town in Nankang District of Ganzhou City, Jiangxi Province, China. The specimen consists of most of an articulated skull in addition to disarticulated parts of the postcrania, comprising much of the right and left legs and several caudal vertebrae. [2]

In 2024, Zheng et al. described Asiatyrannus xui as a new genus and species of tyrannosaurid based on these fossil remains. The generic name, Asiatyrannus, combines "Asia", the continent of origin, with the Latinised Greek suffix "-tyrannus", meaning "tyrant" or "king". The specific name, xui, honors prominent dinosaur researcher Xu Xing and his contributions to paleontological research in China. [2]

Description

Life reconstruction of Asiatyrannus AsiatyrannusScale.png
Life reconstruction of Asiatyrannus
Holotype skull of Asiatyrannus Asiatyrannus (skull - right lateral).png
Holotype skull of Asiatyrannus

Asiatyrannus is a small-medium-sized tyrannosaur. Its nearly complete skull measures 47.5 centimetres (18.7 in) long, and it has an estimated body length of 3.5–4 metres (11–13 ft). In comparison, the mature skull of the closely related Nanuqsaurus from the Prince Creek Formation of North America is estimated at 60–70 centimetres (24–28 in). [3] Since Nanuqsaurus likely had a body size similar to Albertosaurus , Asiatyrannus may represent the only tyrannosaurine in this smaller size class. [4] The Asiatyrannus holotype is about half the length of the contemporary Qianzhousaurus . However, the holotype of Asiatyrannus did not belong to a skeletally mature individual, and as such, it would have been larger when fully grown. Nevertheless, it had probably passed through the life stages of most rapid growth, and other tyrannosaurines in similar growth stages are more than twice as large. [2]

Classification

Using a modified version of the phylogenetic dataset of Carr et al. (2017), [5] Zheng et al. recovered Asiatyrannus as a derived tyrannosaurine member of the Tyrannosauridae, in a polytomy with the North American Nanuqsaurus . These results are displayed in the cladogram below: [2]

Tyrannosauridae

Paleoecology

Asiatyrannus is known from the Nanxiong Formation, which dates to the end of the Maastrichtian age of the late Cretaceous period. Many other dinosaurs have been described from layers of the formation, including the fellow tyrannosaurid Qianzhousaurus . [2] Large teeth indicate the presence of a large, unnamed tyrannosaurid in the ecosystem. [6] Other theropods include therizinosaurids ( Nanshiungosaurus ) [7] and many oviraptorids ( Banji , Corythoraptor , Ganzhousaurus , Huanansaurus , Jiangxisaurus , Nankangia , Shixinggia , and Tongtianlong ). [8] [9] The somphospondylan sauropods Gannansaurus and Jiangxititan are also known from the formation. [10] The formation's non-dinosaurian fauna includes crocodilians ( Jiangxisuchus ), [11] lizards ( Chianghsia and Tianyusaurus ), [12] and turtles ( Jiangxichelys ). [13]

The Mongolian Nemegt Formation contains a similar fauna, including the large tyrannosaurine Tarbosaurus , two species of the alioramin Alioramus , and smaller tyrannosauroids such as Bagaraatan . [14]

See also

Related Research Articles

<span class="mw-page-title-main">Tyrannosauridae</span> Family of dinosaurs

Tyrannosauridae is a family of coelurosaurian theropod dinosaurs that comprises two subfamilies containing up to fifteen genera, including the eponymous Tyrannosaurus. The exact number of genera is controversial, with some experts recognizing as few as three. All of these animals lived near the end of the Cretaceous Period and their fossils have been found only in North America and Asia.

<i>Tarbosaurus</i> Tyrannosaurid dinosaur genus from Late Cretaceous of Mongolia

Tarbosaurus is a genus of large tyrannosaurid dinosaur that lived in Asia during the Late Cretaceous epoch, about 70 million years ago. It contains the single type species: Tarbosaurus bataar, which is known from the Nemegt Formation of Mongolia, with more fragmentary remains found further afield in the Subashi Formation of China. Tarbosaurus is represented by dozens of fossil specimens, including several complete skulls and skeletons. These remains have allowed studies focusing on its phylogeny, skull mechanics, and brain structure. Further fossil remains have been reported from other geologic formations of Asia, however, these remains are fragmentary and can not be confidentially assigned to Tarbosaurus or the type species.

<i>Alioramus</i> Tyrannosaurid theropod dinosaur genus from the Late Cretaceous period

Alioramus is a genus of tyrannosaurid theropod dinosaurs from the Late Cretaceous period of Asia. It currently contains two species. The type species, A. remotus is known from a partial skull and three foot bones recovered from the Mongolian Nemegt Formation, which was deposited in a humid floodplain about 70 million years ago. These remains were named and described by Soviet paleontologist Sergei Kurzanov in 1976. A second species, A. altai, known from a much more complete skeleton also from the Nemegt Formation, was named and described by Stephen L. Brusatte and colleagues in 2009. Its relationships to other tyrannosaurid genera were at first unclear, with some evidence supporting a hypothesis that Alioramus was closely related to the contemporary species Tarbosaurus bataar. However, the discovery of Qianzhousaurus indicates that it belongs to a distinct branch of tyrannosaurs, namely the tribe Alioramini.

<span class="mw-page-title-main">Tyrannosauroidea</span> Extinct superfamily of dinosaurs

Tyrannosauroidea is a superfamily of coelurosaurian theropod dinosaurs that includes the family Tyrannosauridae as well as more basal relatives. Tyrannosauroids lived on the Laurasian supercontinent beginning in the Jurassic Period. By the end of the Cretaceous Period, tyrannosauroids were the dominant large predators in the Northern Hemisphere, culminating in the gigantic Tyrannosaurus. Fossils of tyrannosauroids have been recovered on what are now the continents of North America, Europe and Asia, with fragmentary remains possibly attributable to tyrannosaurs also known from South America and Australia.

<i>Nanshiungosaurus</i> Extinct genus of reptiles

Nanshiungosaurus is a genus of therizinosaurid that lived in what is now Asia during the Late Cretaceous of South China. The type species, Nanshiungosaurus brevispinus, was first discovered in 1974 and described in 1979 by Dong Zhiming. It is represented by a single specimen preserving most of the cervical and dorsal vertebrae with the pelvis. A supposed and unlikely second species, "Nanshiungosaurus" bohlini, was found in 1992 and described in 1997. It is also represented by vertebrae but this species however, differs in geological age and lacks authentic characteristics compared to the type, making its affinity to the genus unsupported.

<span class="mw-page-title-main">Tyrannosaurinae</span> Extinct subfamily of dinosaurs

Tyrannosaurinae is one of the two extinct subfamilies of Tyrannosauridae, a family of coelurosaurian theropods that consists of at least three tribes and several genera. All fossils of these genera have been found in the Late Cretaceous deposits of western North America and east Asia. Compared to the related subfamily Albertosaurinae, tyrannosaurines overall are more robust and larger though the alioramins were gracile by comparison. This subfamily also includes the oldest known tyrannosaurid genus Lythronax as well as the youngest and most famous member of the group, Tyrannosaurus rex. There were at least 30 different species of tyrannosaurines.

The Nanxiong Formation is a Late Cretaceous geologic formation in Guangdong Province. Dinosaur remains are among the fossils that have been recovered from the formation.

<i>Macroolithus</i> Oogenus of dinosaur egg

Macroolithus is an oogenus of dinosaur egg belonging to the oofamily Elongatoolithidae. The type oospecies, M. rugustus, was originally described under the now-defunct oogenus name Oolithes. Three other oospecies are known: M. yaotunensis, M. mutabilis, and M. lashuyuanensis. They are relatively large, elongated eggs with a two-layered eggshell. Their nests consist of large, concentric rings of paired eggs. There is evidence of blue-green pigmentation in its shell, which may have helped camouflage the nests.

<i>Zhuchengtyrannus</i> Tyrannosaurid theropod dinosaur genus from Late Cretaceous period

Zhuchengtyrannus is a genus of tyrannosaurid theropod dinosaur known from the Campanian stage of the Late Cretaceous of Shandong Province, China. It belongs to the subfamily Tyrannosaurinae, and contains a single species, Zhuchengtyrannus magnus.

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

Ganzhousaurus is an extinct genus of oviraptorid dinosaur known from the Late Cretaceous Nanxiong Formation of Nankang County, Ganzhou City of Jiangxi Province, southern China. It was found in a Maastrichtian deposit and contains a single species, Ganzhousaurus nankangensis. It is distinguished by a combination of primitive and derived features.

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

Gannansaurus is an extinct genus of somphospondylan sauropod dinosaur known from the latest Cretaceous Nanxiong Formation of Ganzhou Basin, Jiangxi Province of southern China. It is known from specimen GMNH F10001 which consists of a single, nearly complete dorsal vertebra and a mid-caudal vertebra. Gannansaurus was first named by Lü Junchang, Yi Laiping, Zhong Hui and Wei Xuefang in 2013 and the type species is Gannansaurus sinensis. Gannansaurus shares some characters with Euhelopus, indicating that it is more closely related to it rather than to other titanosauriforms.

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

Jiangxisaurus is an extinct genus of oviraptorid theropod dinosaur from the Late Cretaceous Nanxiong Formation of southern China. It was similar to Heyuannia, but with more strongly curved anterior claws and a thinner, frailer mandible. This find is paleontologically significant because it contributes to current knowledge about the paleogeographical distribution of oviraptorids in southern China. It was most likely an omnivorous animal along with its close relatives Nankangia and Ganzhousaurus.

<i>Lythronax</i> Genus of tyrannosaurid dinosaur from the Late Cretaceous period

Lythronax is a genus of tyrannosaurid dinosaur that lived in North America around 81.9-81.5 million years ago during the Late Cretaceous period. The only known specimen was discovered in Utah in the Wahweap Formation of the Grand Staircase–Escalante National Monument in 2009, and it consists of a partial skull and skeleton. In 2013, it became the basis of the new genus and species Lythronax argestes; the generic name Lythronax means "gore king", and the specific name argestes originates from the Greek poet Homer's name for the wind from the southwest, in reference to the specimen's geographic provenance in North America.

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

Nankangia is an extinct genus of caenagnathoid oviraptorosaurian dinosaur known from the Upper Cretaceous Nanxiong Formation of Nankang County, Ganzhou City of Jiangxi Province, southeastern China. It contains a single species, Nankangia jiangxiensis. N. jiangxiensis coexisted with at least four other caenagnathoids, including but not limited to Corythoraptor, Banji, Ganzhousaurus and Jiangxisaurus. The relatively short dentary and non-downturned mandibular symphysis of Nankangia suggest that it may have been more herbivorous than carnivorous. Its diet consisted of leaves and seeds.

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

Nanuqsaurus is a genus of tyrannosaurine theropod dinosaur known from the Late Cretaceous period Prince Creek Formation of the North Slope of Alaska, having lived roughly 70-68 million years ago. It contains a single species, Nanuqsaurus hoglundi, known only from a partial skull and multiple undescribed postcranial and teeth elements.

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

Qianzhousaurus is a genus of tyrannosaurid dinosaur that lived in Asia during the Maastrichtian age of the Late Cretaceous period. There is currently only one species named, the type species Qianzhousaurus sinensis, which is a member of the tribe Alioramini and most closely related to Alioramus, the only other known alioramin.

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

Alioramini is a clade of long-snouted tyrannosaurine tyrannosaurids from the Late Cretaceous epoch. It includes the tyrannosaurid genera Alioramus and Qianzhousaurus. Although tyrannosaurids are known from a variety of places around the globe, alioramins are currently restricted to Asia in mostly Maastrichtian strata. Many of the fossils attributed to Alioramini are not from fully developed individuals.

<span class="mw-page-title-main">Timeline of tyrannosaur research</span>

This timeline of tyrannosaur research is a chronological listing of events in the history of paleontology focused on the tyrannosaurs, a group of predatory theropod dinosaurs that began as small, long-armed bird-like creatures with elaborate cranial ornamentation but achieved apex predator status during the Late Cretaceous as their arms shrank and body size expanded. Although formally trained scientists did not begin to study tyrannosaur fossils until the mid-19th century, these remains may have been discovered by Native Americans and interpreted through a mythological lens. The Montana Crow tradition about thunder birds with two claws on their feet may have been inspired by isolated tyrannosaurid forelimbs found locally. Other legends possibly inspired by tyrannosaur remains include Cheyenne stories about a mythical creature called the Ahke, and Delaware stories about smoking the bones of ancient monsters to have wishes granted.

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

Tongtianlong is a genus of oviraptorid theropod dinosaurs that lived in the late Maastrichtian epoch of the late Cretaceous period. It contains one species, T. limosus.

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

Corythoraptor is a genus of oviraptorid dinosaur from the late Maastrichtian Nanxiong Formation of South China. It contains one species, C. jacobsi, known from a single well-preserved skeleton, and named after paleontologist Louis L. Jacobs. It bears a tall crest similar to that of the modern cassowary, and possibly had a similar functionality of display and resonance to detect lower-frequency sounds.

References

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