Aviatyrannis

Last updated

Aviatyrannis
Temporal range: Late Jurassic,
160–145  Ma
Aviatyrannis remains 01.png
Diagram of fossils assigned to Aviatyrannis
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Saurischia
Clade: Theropoda
Clade: Orionides
Clade: Avetheropoda
Clade: Coelurosauria
Genus: Aviatyrannis
Rauhut, 2003
Species:
A. jurassica
Binomial name
Aviatyrannis jurassica
Rauhut, 2003

Aviatyrannis is a genus of coelurosaurian theropod dinosaur, either a tyrannosauroid or an ornithomimosaurian, from the Oxfordian-Tithonian stages of the Late Jurassic found in Portugal.

Contents

Discovery and naming

In 2000 Oliver Walter Mischa Rauhut reported the find of tyrannosauroid material in the lignite coal mine of Guimarota near Leiria, which he referred to Stokesosaurus . [1] Later concluding the distinctiveness of the material justified a separate genus, Rauhut in 2003 named and described it as the type species Aviatyrannis jurassica. [2] The species name was by Rauhut given the intended meaning of "tyrant's grandmother from the Jurassic". [2] The generic name is derived from Latin avia, "grandmother", and tyrannus, "tyrant", on the presumption tyrannis would be its genitive. [2] The specific name means "Jurassic". [2]

The holotype, IPFUB Gui Th 1, was found in a layer of the Alcobaça Formation dating from the early Kimmeridgian, about 155 million years old. It consists of a right ilium. Rauhut in 2003 referred two other bones to Aviatyrannis: IPFUB Gui Th 2, a partial right ilium, and IPFUB Gui Th 3, a right ischium. The referred elements represent slightly larger individuals. Additionally sixteen isolated teeth were referred: IPFUB GUI D 89-91: three teeth of the premaxilla, and IPFUB GUI D 174-186: thirteen teeth of the maxilla and dentary. [2] These had in 1998 been described by Jens Zinke. [3] Rauhut also hypothesised that a number of specimens referred to Stokesosaurus might actually belong to Aviatyrannis. [2]

Description

Estimated size of Aviatyrannis (here depicted as a tyrannosauroid). Aviatyrannis estimated size 01.png
Estimated size of Aviatyrannis (here depicted as a tyrannosauroid).

Aviatyrannis was a rather small theropod. The holotype specimen IPFUB Gui Th 1, for example, is an ilium only ninety millimeters long. In 2016, Gregory S. Paul estimated its length at 1 m (3.3 ft) and its body mass at 4 kg (8.8 lb); he also suggested that the holotype possibly belongs to a juvenile. [4] The ilium is elongated and low with the typical tyrannosauroid vertical ridge on the outer blade surface above the hip joint. [2] The teeth of the praemaxilla have a D-shaped cross-section. The maxillary and dentary teeth are elongated, only recurving near the top, with perpendicular denticles on both edges. Their bases are circular in cross-section; the top of the tooth crown is more flattened. [3]

Classification

Aviatyrannis was in 2003 by Rauhut placed in the Tyrannosauroidea, in a basal position. [2] If this placement is correct, Aviatyrannis is one of the oldest tyrannosauroids ever found, the oldest being Proceratosaurus (or, possibly, Iliosuchus ). [2] However, a 2023 paper by Hattori et al. noted that the Aviatyrannis ilium is strikingly similar to that of the newly described deinocheirid Tyrannomimus . The authors argue that, though more detailed study is needed, Aviatyrannis could be the earliest known ornithomimosaur and possibly the earliest known deinocheirid, with one analysis recovering it as a sister taxon of Tyrannomimus and the other recovering it as an ornithomimosaur outside deinocheirids and ornithomimids. The results of their phylogenetic analyses are displayed in the cladogram below: [5]

Ornithomimosauria

See also

Related Research Articles

<i>Torvosaurus</i> Megalosaurid theropod dinosaur genus from Late Jurassic Period

Torvosaurus is a genus of large megalosaurine theropod dinosaur that lived approximately 165 to 148 million years ago during the Callovian to Tithonian ages of the late Middle and Late Jurassic period in what is now Colorado, Portugal, Germany, and possibly England, Spain, Tanzania, and Uruguay. It contains two currently recognized species, Torvosaurus tanneri and Torvosaurus gurneyi, plus a third unnamed species from Germany.

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

Proceratosaurus /proʊ̯sɛrətoʊˈsɔːrəs/ is a genus of carnivorous theropod dinosaur from the Middle Jurassic (Bathonian) of England. It contains a single species. P. bradleyi, known from a mostly complete skull and lower jaws. Proceratosaurus was a small dinosaur, estimated to measure around 3 m (9.8 ft) in length. Its name refers to how it was originally thought to be an ancestor of Ceratosaurus, due to the partially preserved portion of the crest of Proceratosaurus superficially resembling the small crest of Ceratosaurus. Now, however, it is considered a coelurosaur, specifically a member of the family Proceratosauridae, and amongst the earliest known members of the clade Tyrannosauroidea.

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

Monolophosaurus is an extinct genus of tetanuran theropod dinosaur from the Middle Jurassic Shishugou Formation in what is now Xinjiang, China. It was named for the single crest on top of its skull. Monolophosaurus was a mid-sized theropod at about 5–5.5 metres (16–18 ft) long and weighed 475 kilograms (1,047 lb).

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

Siamotyrannus is a genus of theropod dinosaur from the early Cretaceous of Thailand.

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

Stokesosaurus is a genus of small, carnivorous early tyrannosauroid theropod dinosaurs from the late Jurassic period of Utah, United States and Guimarota, Portugal.

<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>Dryptosaurus</i> Extinct genus of dinosaurs

Dryptosaurus is a genus of eutyrannosaurian theropod dinosaur that lived on the island continent of Appalachia approximately 67-66 million years ago during the end of the Maastrichtian age of the Late Cretaceous period. Dryptosaurus was a large, bipedal, ground-dwelling carnivore that could grow up to 7.5 metres (25 ft) long and weigh up to 756–1,500 kilograms (1,667–3,307 lb). Although it is now largely unknown outside of academic circles, the famous 1897 painting of the genus by Charles R. Knight made Dryptosaurus one of the more widely known dinosaurs of its time, in spite of its poor fossil record. First described by Edward Drinker Cope in 1866 and later renamed by Othniel Charles Marsh in 1877, Dryptosaurus is among the first theropod dinosaurs ever known to science.

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

Guanlong (冠龍) is a genus of extinct proceratosaurid tyrannosauroid dinosaur from the Late Jurassic of China. The taxon was first described in 2006 by Xu Xing et al., who found it to represent a new taxon related to Tyrannosaurus. The name is derived from Chinese, translating as "crown dragon". Two individuals are currently known, a partially complete adult and a nearly complete juvenile. These specimens come from the Oxfordian stage of the Chinese Shishugou Formation.

<i>Bagaraatan</i> Extinct genus of theropod dinosaurs

Bagaraatan is a genus of theropod dinosaur from the Late Cretaceous period. Its fossils were found in the Nemegt Formation of Mongolia. Bagaraatan may have been around 3 to 4 metres in length.

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

Tanycolagreus is a genus of coelurosaurian theropod from the Late Jurassic of North America.

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

Nuthetes is the name given to a genus of coelurosaurian theropod dinosaur, either a dromaeosaurid or a tyrannosauroid, known only from fossil teeth and jaw fragments found in rocks of the middle Berriasian age in the Cherty Freshwater Member of the Lulworth Formation in England and also the Angeac-Charente bonebed in France. If it was a dromaeosaurid, Nuthetes would have been a small predator.

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

Xiongguanlong is an extinct genus of tyrannosauroid theropod from the Early Cretaceous period of what is now China. The type and only species is X. baimoensis. The generic name comes from Jiayuguan City and the Mandarin word "long" which means dragon. The specific epithet, "baimoensis" is a latinization of the Mandarin word for "white ghost" in reference to one of the geological features of the type locality.

Lusitanisuchus is an extinct genus of mesoeucrocodylian crocodyliform. Mostly fragmentary fossils have been found from several localities in Portugal and are Late Jurassic and Early Cretaceous in age.

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

Sinotyrannus was an early, large-bodied genus within the superfamily Tyrannosauroidea. This dinosaur had a single type species, S. kazuoensis, with the only known specimen containing a partial skull, some vertebrae, and a hip, all of which were found in the Early Cretaceous aged Jiufotang Formation of Liaoning, China. While it exhibited greater body size that would put it on par with the later tyrannosaurids such as Tyrannosaurus, Sinotyrannus was probably a member of the basal tyrannosaur family known as the Proceratosauridae. This family originated in the Jurassic, whose members are known from Europe and Asia. Sinotyrannus, alongside another early tyrannosaur, Yutyrannus, appears to have been oddly large when compared to most tyrannosaurs of the Early Cretaceous, such as Dilong. Most of the world during the Early Cretaceous was dominated by more basal tetanurans, such as the megalosaurs and allosaurs, with tyrannosaurids themselves only taking over after both groups started to decline. However, Sinotyrannus and Yutyrannus appear to be exceptions to this. Sinotyrannus was the largest theropod in the Jiufotang Formation, reaching up to 10 meters in overall length and having a general mass similar to that of a large rhino.

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

Proceratosauridae is a family or clade of tyrannosauroid theropod dinosaurs from the Middle Jurassic to the Early Cretaceous.

<i>Juratyrant</i> Genus of dinosaurs

Juratyrant is a tyrannosauroid dinosaur genus from the late Jurassic period of England. The genus contains a single species, Juratyrant langhami, which was once classed as a species of Stokesosaurus.

<i>Siats</i> Extinct genus of theropod dinosaurs

Siats (/see-ats/) is an extinct genus of large theropod dinosaurs known from the Late Cretaceous Cedar Mountain Formation of Utah, United States. The genus contains a single species, Siats meekerorum. It was initially classified as a megaraptoran, a clade of large theropods with controversial relationships. Alternative positions within the Neovenatoridae, Allosauroidea, and Tyrannosauroidea have also been proposed.

<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>Knoetschkesuchus</i> Extinct genus of reptiles

Knoetschkesuchus is a genus of small atoposaurid crocodylomorph from the Late Jurassic of Germany and Portugal. Two species are known: the German species K. langenbergensis, described by Schwarz and colleagues in 2017 based on two partial skeletons and various isolated bones; and the Portuguese species K. guimarotae, named from over 400 specimens including several partial skeletons. Knoetschkesuchus was a small and short-snouted crocodilian, measuring about 55 centimetres (22 in) in length, that primarily fed on small prey, including invertebrates, amphibians, and mammals. This specialization towards small prey ecologically separated Knoetschkesuchus from most of the other diverse crocodilians that it lived with in the island ecosystem of Jurassic Europe.

<i>Tyrannomimus</i> Extinct genus of ornithomimosaurian dinosaurs

Tyrannomimus is an extinct genus of ornithomimosaurian theropod dinosaurs from the Kitadani Formation of Japan. The type species is Tyrannomimus fukuiensis.

References

  1. Rauhut, O.W.M., 2000, "The dinosaur fauna from the Guimarota mine", pp 75-82 In: Martin and Krebs (eds.). Guimarota - A Jurassic Ecosystem Verlag Dr. Friedrich Pfeil, München
  2. 1 2 3 4 5 6 7 8 9 Oliver W. M. Rauhut. (2003). "A tyrannosauroid dinosaur from the Upper Jurassic of Portugal". Palaeontology. 46 (5): 903–910. Bibcode:2003Palgy..46..903R. doi: 10.1111/1475-4983.00325 .
  3. 1 2 Zinke, J., 1998, "Small theropod teeth from the Upper Jurassic coal mine of Guimarota (Portugal)", Paläontologische Zeitschrift72(1/2): 179-189
  4. Paul, Gregory S. (2016). The Princeton Field Guide to Dinosaurs. Princeton University Press. p. 106. ISBN   978-1-78684-190-2. OCLC   985402380.
  5. Hattori, Soki; Shibata, Masateru; Kawabe, Soichiro; Imai, Takuya; Nishi, Hiroshi; Azuma, Yoichi (2023-09-07). "New theropod dinosaur from the Lower Cretaceous of Japan provides critical implications for the early evolution of ornithomimosaurs". Scientific Reports. 13 (1): 13842. Bibcode:2023NatSR..1313842H. doi: 10.1038/s41598-023-40804-3 . ISSN   2045-2322. PMC   10484975 . PMID   37679444.