Piatnitzkysauridae

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Piatnitzkysaurids
Temporal range: Early - Late Jurassic, 179–152  Ma
Piatnitzkysaurus.jpg
Piatnitzkysaurus , type genus of the Piatnitzkysauridae
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Saurischia
Clade: Theropoda
Clade: Carnosauria (?)
Family: Piatnitzkysauridae
Carrano, Benson & Sampson, 2012
Type species
Piatnitzkysaurus floresi
Bonaparte, 1979
Genera

Piatnitzkysauridae is an extinct family of megalosauroid or basal allosauroid dinosaurs. It only consists of three to four known dinosaur genera: Condorraptor , Marshosaurus , Piatnitzkysaurus and possibly Xuanhanosaurus. The most complete and well known member of this family is Piatnitzkysaurus, which also gives the family its name. [1]

Description

A skull of Marshosaurus showing the maxilla Marshosaurus.jpg
A skull of Marshosaurus showing the maxilla

So far all known piatnitzkysaurids have only been found in Jurassic deposits of the western hemisphere/New world (however, if Xuanhanosaurus is included than this may expand their range). [2] Piatnitzkysaurus and Condorraptor hail from the Cañadón Asfalto Formation of Argentina, which has been dated from the Toarcian epoch of the Early Jurassic to the Bathonian epoch of the Middle Jurassic (approximately 179 to 168 million years ago). Marshosaurus was found in the Morrison Formation of the United States, which was dated to the Kimmeridgian epoch of the Late Jurassic.

Piatnitzkysaurids were among the first large theropods present in South America, and are evidence for a radiation of basal tetanurans in the middle Jurassic. [1] Although there is support for basal megalosauroid affinities, piatnitzkysaurids also share some traits with allosaurids, such as a 'sigmoidal' humerus. It has been proposed that they are basal Allosaurs or Non Megalosaurian Megalosauroids.

If Piatnitzkysaurids are Megalosauroids, they can be distinguished from other megalosauroids and placed into their own category due to the following synapomorphies (distinguishing features): [1]

In addition, this family shows several reversals to basal Tetanuran traits. These include: [1]

Classification

Life restoration of Piatnitzkysaurus Piatnitzkysaurus floresi by Paleocolour.jpg
Life restoration of Piatnitzkysaurus

Piatnitzkysauridae is defined as all members of Megalosauroidea more closely related to Piatnitzkysaurus than to either Spinosaurus or Megalosaurus . Condorraptor, Marshosaurus, and Piatnitzkysaurus were all placed in a clade by Benson in 2010 during a redescription of Megalosaurus. [3] This clade was defined as a family by Carrano et al in 2012. Piatnitzkysauridae has been recovered as the sister taxa to Megalosauria, a clade containing the megalosaurids (such as Megalosaurus and Torvosaurus ) and the spinosaurids (such as Spinosaurus and Baryonyx ). [1]

Condorraptor and Piatnitzkysaurus are generally grouped together within this family in a clade excluding Marshosaurus. This is not only due to Condorraptor and Piatnitzkysaurus being from the same locality and time period, but also due to them having flat anterior faces of presacral vertebrae as well as a pronounced ventral keel on the anterior dorsal vertebrae. [1] [3] Due to the strong resemblance to Piatnitzkysaurus, it has been suggested that the sister taxa Condorraptor could be better interpreted as the result of individual variation within the species, and not as separate taxa. The main noted differences between the two dinosaurs include both a less well developed enemial crest and a first sacral vertebra with a shallower fossa in Condorraptor. [4]

Xuanhanosaurus , a problematic tetanuran with uncertain affinities, was placed as the sister taxon of these three genera when their relation was first observed in 2010. [3] However, due to the incompleteness of Xuanhanosaurus's remains, this placement is considered uncertain. Other studies have considered Xuanhanosaurus a basal tetanuran. [1] Xuanhanosaurus is still sometimes found as a Piatnitzkysauridae. [5]

In 2019, Rauhut and Pol described Asfaltovenator vialidadi , a basal allosauroid displaying a mosaic of primitive and derived features seen within Tetanurae. Their phylogenetic analysis found traditional Megalosauroidea to represent a basal grade of carnosaurs, paraphyletic with respect to Allosauroidea. Because the authors amended the definition of Allosauroidea to include all theropods that are closer to Allosaurus fragilis than to either Megalosaurus bucklandii or Neornithes, the Piatnitzkysauridae was found to fall within Allosauroidea. A cladogram displaying the relationships they recovered is shown below: [6]

Carnosauria

Related Research Articles

<span class="mw-page-title-main">Carnosauria</span> Extinct group of theropod dinosaurs

Carnosauria is an extinct group of carnivorous theropod dinosaurs that lived during the Jurassic and Cretaceous periods.

<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.

<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.

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

Allosauridae is a family of medium to large bipedal, carnivorous allosauroid theropod dinosaurs from the Late Jurassic. Allosauridae is a fairly old taxonomic group, having been first named by the American paleontologist Othniel Charles Marsh in 1878. Allosaurids are characterized by an astragalus with a restriction of the ascending process to the lateral part of the bone, a larger medial than lateral condyle, and a horizontal groove across the face of the condyles.

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

Megalosauridae is a monophyletic family of carnivorous theropod dinosaurs within the group Megalosauroidea. Appearing in the Middle Jurassic, megalosaurids were among the first major radiation of large theropod dinosaurs. They were a relatively primitive group of basal tetanurans containing two main subfamilies, Megalosaurinae and Afrovenatorinae, along with the basal genus Eustreptospondylus, an unresolved taxon which differs from both subfamilies.

<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>Piatnitzkysaurus</i> Extinct genus of dinosaurs

Piatnitzkysaurus is a genus of megalosauroid theropod dinosaur that lived approximately 179 to 177 million years ago during the lower part of the Jurassic Period in what is now Argentina. Piatnitzkysaurus was a moderately large, lightly built, bipedal, ground-dwelling carnivore that could grow up to 6.6 m (21.7 ft) long.

<span class="mw-page-title-main">Megalosauroidea</span> Extinct superfamily of Dinosaurs

Megalosauroidea is a superfamily of tetanuran theropod dinosaurs that lived from the Middle Jurassic to the Late Cretaceous period. The group is defined as Megalosaurus bucklandii and all taxa sharing a more recent common ancestor with it than with Allosaurus fragilis or Passer domesticus. Members of the group include Spinosaurus, Megalosaurus, and Torvosaurus. They are possibly paraphyletic in nature with respect to Allosauroidea.

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

Xuanhanosaurus is a genus of theropod dinosaur that lived during the Middle Jurassic (Bathonian) of the Sichuan Basin, China, around 166 million years ago. This taxon represents one of the various non-coelurosaurian tetanuran taxa found on the Middle Jurassic of the region, uncovered in the Lower Shaximiao Formation. Although it has been known for more than 40 years, this taxon has been the subject of very few studies, although most seem to agree that it is a tetanuran, possibly a basal allosauroid, highlighting the fact that it has a vestigial fourth metacarpal.

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

Magnosaurus was a genus of theropod dinosaur from the Middle Jurassic of England. It is based on fragmentary remains and has often been confused with or included in Megalosaurus.

Chuandongocoelurus is a genus of carnivorous tetanuran theropod dinosaur from the Jurassic of China.

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

Condorraptor is an extinct genus of megalosauroid theropod dinosaur. Its genus name means 'robber from Cerro Condor', referencing a nearby village, while its species name, currumili, is named after Hipolito Currumil, the landowner and discoverer of the locality. It was among the earliest large South American theropods, having been found in Lower Jurassic strata of the Cañadón Asfalto Formation in the Cañadón Asfalto Basin of Argentina. The type species, described in 2005, is Condorraptor currumili. It is based on a tibia, with an associated partial skeleton that may belong to the same individual. Initially described as a basal tetanuran, Benson (2010) found it to be a piatnitzkysaurid megalosauroid and the sister taxon of Piatnitzkysaurus, a finding supported by later studies.

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

Metriacanthosauridae is an extinct family of allosauroid theropod dinosaurs that lived from the Middle Jurassic to the Early Cretaceous. When broken down into its Greek roots, it means "moderately-spined lizards". The family is split into two subgroups: Metriacanthosaurinae, which includes dinosaurs closely related to Metriacanthosaurus, and another group composed of the close relatives of Yangchuanosaurus. Metriacanthosaurids are considered carnosaurs, belonging to the Allosauroidea superfamily. The group includes species of large range in body size. Of their physical traits, most notable are their neural spines. The records of the group are mostly confined to Asia, though Metriacanthosaurus is known from Europe. Metriacanthosauridae is used as a senior synonym of Sinraptoridae.

<span class="mw-page-title-main">Allosauroidea</span> Extinct superfamily of Dinosaurs

Allosauroidea is a superfamily or clade of theropod dinosaurs which contains four families — the Metriacanthosauridae, Allosauridae, Carcharodontosauridae, and Neovenatoridae. Allosauroids, alongside the family Megalosauroidea, were among the apex predators that were active during the Middle Jurassic to Late Cretaceous periods. The most famous and best understood allosauroid is the North American genus Allosaurus.

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

Poekilopleuron is a genus of tetanuran dinosaur, which lived during the middle Bathonian of the Jurassic, about 168 to 166 million years ago. The genus has been used under many different spelling variants, although only one, Poekilopleuron, is valid. The type species is P. bucklandii, named after William Buckland, and many junior synonyms of it have also been erected. Little material is currently known, as the holotype was destroyed in World War II, although many casts of the material still exist.

<span class="mw-page-title-main">Avetheropoda</span> Clade of dinosaurs

Avetheropoda, or "bird theropods", is a clade that includes Carnosaurs and coelurosaurs to the exclusion of other Dinosaurs.

<i>Duriavenator</i> Genus of theropod dinosaur

Duriavenator is a genus of theropod dinosaur that lived in what is now England during the Middle Jurassic, about 168 million years ago. In 1882, upper and lower jaw bones of a dinosaur were collected near Sherborne in Dorset, and Richard Owen considered the fossils to belong to the species Megalosaurus bucklandii, the first named non-bird dinosaur. By 1964, the specimen was recognised as belonging to a different species, and in 1974 it was described as a new species of Megalosaurus, M. hesperis; the specific name means 'the West' or 'western'. Later researchers questioned whether the species belonged to Megalosaurus, in which many fragmentary theropods from around the world had historically been placed. After examining the taxonomic issues surrounding Megalosaurus, Roger B. J. Benson moved M. hesperis to its own genus in 2008, Duriavenator; this name means "Dorset hunter".

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

Cruxicheiros is a genus of theropod dinosaur which lived in the Middle Jurassic of England. The type species is C. newmanorum, described by Roger Benson and Jonathan Radley in 2010.

<span class="mw-page-title-main">Orionides</span> Clade of dinosaurs

Orionides is a clade of tetanuran theropod dinosaurs from the Middle Jurassic to the Present. The clade includes most theropod dinosaurs, including birds.

<i>Asfaltovenator</i> Extinct genus of theropod dinosaur

Asfaltovenator is a genus of possibly allosauroid dinosaur from the Lower Jurassic Cañadón Asfalto Formation from Chubut Province, Argentina. The type and only species is Asfaltovenator vialidadi.

References

  1. 1 2 3 4 5 6 7 Carrano, M. T.; Benson, R. B. J.; Sampson, S. D. (2012). "The phylogeny of Tetanurae (Dinosauria: Theropoda)". Journal of Systematic Palaeontology. 10 (2): 211–300. doi:10.1080/14772019.2011.630927. S2CID   85354215.
  2. "Piatnitzkysauridae". Paleobiology Database. Retrieved 20 June 2013.
  3. 1 2 3 4 BENSON, ROGER B. J. (2010-04-01). "A description ofMegalosaurus bucklandii(Dinosauria: Theropoda) from the Bathonian of the UK and the relationships of Middle Jurassic theropods". Zoological Journal of the Linnean Society. 158 (4): 882–935. doi: 10.1111/j.1096-3642.2009.00569.x . ISSN   0024-4082.
  4. Novas, Fernando (2009). The Age of Dinosaurs in South America. Indiana University Press. p. 118. ISBN   0253352894.
  5. Rauhut, Oliver (2016). "A new megalosaurid theropod dinosaur from the late Middle Jurassic (Callovian) of north-western Germany: Implications for theropod evolution and faunal turnover in the Jurassic". Palaeontologia Electronica. 19 (2). doi: 10.26879/654 .
  6. Rauhut, Oliver W. M.; Pol, Diego (2019-12-11). "Probable basal allosauroid from the early Middle Jurassic Cañadón Asfalto Formation of Argentina highlights phylogenetic uncertainty in tetanuran theropod dinosaurs". Scientific Reports. 9 (1): 18826. doi:10.1038/s41598-019-53672-7. ISSN   2045-2322. PMC   6906444 . PMID   31827108.