Inawentu

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Inawentu
Temporal range: Late Cretaceous, Santonian
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Inawentu oslatus.png
Life restoration
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Saurischia
Clade: Sauropodomorpha
Clade: Sauropoda
Clade: Macronaria
Clade: Titanosauria
Clade: Eutitanosauria
Genus: Inawentu
Filippi et al., 2023
Species:
I. oslatus
Binomial name
Inawentu oslatus
Filippi et al., 2023

Inawentu (meaning "imitator") is an extinct genus of titanosaurian sauropod dinosaur from the Late Cretaceous Bajo de la Carpa Formation of Argentina. The genus contains a single species, I. oslatus, known from a partial articulated skeleton including the skull. The square-shaped jaw of Inawentu demonstrates convergent characteristics with rebbachisaurids. [1]

Discovery and naming

The Inawentu holotype specimen, MAU-Pv-LI-595, was discovered in sediments of the Bajo de la Carpa Formation (Neuquén Group) near Rincón de los Sauces in Neuquén Province, Argentina. The specimen consists of a partial articulated skeleton, including a nearly complete skull, all of the vertebrae from the atlas to the end of the sacrum (comprising twelve cervical, ten dorsal, and six sacral vertebrae), and both ilia. [1] MAU-Pv-LI-595 is one of the few known titanosaur specimens to preserve a complete neck. [2]

In 2016, the find was presented at a conference in Argentina. [3] [2] In 2023, Filippi et al. described Inawentu oslatus as a new genus and species of titanosaurian sauropod based on these fossil remains. The generic name, "Inawentu", is derived from a Mapundungun word meaning "mimic" or "imitator". The specific name, "oslatus", combines the Latin words "os", meaning "mouth" and "latus", meaning "broad". [1]

Description

The skull of Inawentu showed several convergent similarities to rebbachisaurids such as Nigersaurus , such as a wide, squared-off snout that was deflected strongly downward. The neck of Inawentu consisted of only twelve vertebrae, fewer than in any other known titanosaur. [1] MCT 1487-R, a specimen possibly referable to Uberabatitan , [4] has thirteen, Futalognkosaurus has fourteen, and Rapetosaurus has seventeen. Thus, Inawentu may have had a proportionately shorter neck than most titanosaurs. The centra and neural arches of the neck and back vertebrae are highly modified, which suggests that the neck would have been capable of multidirectional movement. As in most titanosaurs, there were ten dorsal and six sacral vertebrae. The hips were narrower than in Saltasaurus and Neuquensaurus . [1]

Classification

Filippi et al. (2023) recovered Inawentu as a member of a previously unrecognized clade of square-jawed eutitanosaurs, which they referred to as "Clade A", as the sister taxon to Antarctosaurus . Their results differ from many previous studies, which usually found a close relationship between lognkosaurs and rinconsaurs, but similar results had been previously found by Gorscak and O'Connor in 2016. [1] [5] The results of their phylogenetic analyses are shown in the cladogram below: [1]

Titanosauria

Paleoecology

The Bajo de la Carpa Formation, where Inawentu was found, preserves an ecosystem including other titanosaurs, including other members of "Clade A": Bonitasaura, Rinconsaurus, and Overosaurus. [6]

Related Research Articles

<i>Argentinosaurus</i> Late Cretaceous giant sauropod dinosaur genus

Argentinosaurus is a genus of giant sauropod dinosaur that lived during the Late Cretaceous period in what is now Argentina. Although it is only known from fragmentary remains, Argentinosaurus is one of the largest known land animals of all time, perhaps the largest, measuring 30–35 metres (98–115 ft) long and weighing 65–80 tonnes. It was a member of Titanosauria, the dominant group of sauropods during the Cretaceous. It is widely regarded by many paleontologists as the biggest dinosaur ever, and perhaps lengthwise the longest animal ever, though both claims have no concrete evidence yet.

<i>Antarctosaurus</i> Sauropod dinosaur genus from Late Cretaceous

Antarctosaurus is a genus of titanosaurian sauropod dinosaur from the Late Cretaceous Period of what is now South America. The type species, Antarctosaurus wichmannianus, and a second species, Antarctosaurus giganteus, were described by prolific German paleontologist Friedrich von Huene in 1929. Three additional species of Antarctosaurus have been named since then but later studies have considered them dubious or unlikely to pertain to the genus.

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

Aeolosaurus is a genus of titanosaurian sauropod dinosaur from the Late Cretaceous Period of what is now South America. Like most sauropods, it would have been a quadrupedal herbivore with a long neck and tail. Aeolosaurus is well known for a titanosaur, as it is represented by the remains of several individuals belonging to at least two species. However, like most titanosaurs, no remains of the skull are known. The holotype of Aeolosaurus rionegrinus consists of a series of seven tail vertebrae, as well as parts of both forelimbs and the right hindlimb. It was discovered in the Angostura Colorada Formation in Argentina, which dates from the Campanian stage of the Late Cretaceous, about 83 to 74 million years ago. The species A. maximus was transferred over to the new genus Arrudatitan in 2021.

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

Bonitasaura is a genus of titanosaurian dinosaur hailing from uppermost layers of the Late Cretaceous (Santonian) Bajo de la Carpa Formation, Neuquén Group of the eastern Neuquén Basin, located in Río Negro Province, Northwestern Patagonia, Argentina. The remains, consisting of a partial sub-adult skeleton jumbled in a small area of fluvial sandstone, including a lower jaw with teeth, a partial vertebrae series, and limb bones, were described by Sebastian Apesteguía in 2004.

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

Rinconsaurus is a genus of titanosaur sauropod dinosaur from the Late Cretaceous in what is now Argentina. The type species, Rinconsaurus caudamirus, was described by Calvo and Riga in 2003, and is based on three partial skeletons.

The Bajo de la Carpa Formation is a geologic formation of the Neuquén Basin that crops out in northern Patagonia, in the provinces of Río Negro and Neuquén, Argentina. It is the oldest of two formations belonging to the Río Colorado Subgroup within the Neuquén Group. Formerly, that subgroup was treated as a formation, and the Bajo de la Carpa Formation was known as the Bajo de la Carpa Member.

<span class="mw-page-title-main">Anacleto Formation</span> Geologic formation in Argentina

The Anacleto Formation is a geologic formation with outcrops in the Argentine Patagonian provinces of Mendoza, Río Negro, and Neuquén. It is the youngest formation within the Neuquén Group and belongs to the Río Colorado Subgroup. Formerly that subgroup was treated as a formation, and the Anacleto Formation was known as the Anacleto Member.

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

Uberabatitan is a genus of titanosaurian sauropod dinosaur from the Late Cretaceous of Brazil. It is known from bones including neck, back, and tail vertebrae, pelvic bones, and limb bones. These fossils were found in the uppermost portion of the Maastrichtian-age Serra da Galga Formation of the Bauru Group, in Uberaba, Minas Gerais. The type species, described by Salgado and Carvalho in 2008, is U. ribeiroi. To date, it is the most recent titanosaur from Bauru Group rocks; other titanosaurs from the Bauru Group, including Baurutitan and Trigonosaurus, come from lower levels.

<span class="mw-page-title-main">Lognkosauria</span> Clade of titanosaurian sauropods

Lognkosauria is a clade of giant long-necked sauropod dinosaurs within the clade Titanosauria. It includes some of the largest and heaviest dinosaurs known. They lived in South America and likely Asia during the Late Cretaceous period.

Traukutitan is a genus of titanosaur sauropod dinosaur which lived during the late Cretaceous.

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

Aeolosaurini is an extinct clade of titanosaurian dinosaurs known from the Cretaceous period of Argentina and Brazil. Rodrigo M. Santucci and Antonio C. de Arruda-Campos (2011) in their cladistic analysis found Aeolosaurus, Gondwanatitan, Maxakalisaurus, Panamericansaurus and Rinconsaurus to be aeolosaurids.

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

Overosaurus is an extinct genus of sauropod dinosaurs, containing only a single species, Overosaurus paradasorum. This species lived approximately 86 to 84 million years ago during the latter part of the Cretaceous Period in what is now Patagonia. Overosaurus paradasorum was relatively small compared to other sauropods from Patagonia, like the saltasaurids and other aeolosaurines, estimated as approximately 10 m (33 ft). It was a ground-dwelling herbivore.

<span class="mw-page-title-main">Eutitanosauria</span>

Eutitanosauria is a clade of titanosaurs, encompassing the more derived members of the group and characterized by the absence of the hyposphene-hypantrum articulation and possibly the presence of osteoderms. The group was first named by Sanz and colleagues in 1999, who used it to unite the group of Argyrosaurus, Lirainosaurus, Saltasaurus and the Peiropolis titanosaur. However, this definition was not used as it made the group equivalent to Saltasauridae, so Saldago redefined it in 2003 to be all titanosaurs closer to Saltasaurus than Epachthosaurus. This definition created Eutitanosauria as the sister group to Epachthosaurinae, but was problematic due to the variable nature of Epachthosaurus. Eutitanosauria was often broadly similar to Lithostrotia, and has often been unused or unlabelled on phylogenies. Sometimes Epachthosaurus would be more primitive than Malawisaurus, making Eutitanosauria more encompassing than Lithostrotia, or Epachthosaurus could nest close to Colossosauria and limit Eutitanosauria to a smaller group of saltasauroids. Because of the flexible nature of Epachthosaurus in basal titanosaur phylogeny, Carballido and colleagues redefined the group in 2022 to include the smallest clade of both Patagotitan, a colossosaur, and Saltasaurus, creating a node-stem clade with Colossosauria and Saltasauroidea, presenting the informal cladogram of stable titanosaur clades below.

Brasilotitan is a genus of titanosaurian sauropod dinosaur from the Late Cretaceous Adamantina Formation of Brazil. The type species is Brasilotitan nemophagus. Brasilotitan was a small titanosaur with a squared-off snout, and may be closely related to another Brazilian titanosaur, Uberabatitan.

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

Austroposeidon is a genus of titanosaurian sauropod dinosaur from the Late Cretaceous Presidente Prudente Formation of Brazil. It contains one species, Austroposeidon magnificus.

Choconsaurus is an extinct genus of herbivorous sauropod dinosaur belonging to the group Titanosauriformes, which lived in the area of present-day Argentina at the end of the Cretaceous.

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

Rinconsauria is an extinct clade of giant titanosaurian sauropods known from the late Cretaceous period of Argentina.

<span class="mw-page-title-main">Furileusauria</span> Clade of abelisaurid theropod dinosaurs

Furileusauria is an extinct clade of derived abelisaurid dinosaurs only known from South American fossil remains. They represent some of the largest members of the Abelisauridae, with an average length of 7.1 ± 2.1 m (23.3 ± 6.9 ft). The clade is defined as the most inclusive clade containing Carnotaurus sastrei but not Ilokelesia aguadagrandensis, Skorpiovenator bustingorryi, or Majungasaurus crenatissimus.

Llukalkan is a genus of abelisaurid theropod dinosaur from the Late Cretaceous Bajo de la Carpa Formation of Argentina. The type species is Llukalkan aliocranianus.

Sidersaura is an extinct genus of rebbachisaurid sauropod dinosaur from the Late Cretaceous Huincul Formation of Argentina. The genus contains a single species, S. marae, known from the remains of four individuals. Sidersaura represents one of the largest known rebbachisaurids.

References

  1. 1 2 3 4 5 6 7 Filippi, Leonardo S.; Juárez Valieri, Rubén D.; Gallina, Pablo A.; Méndez, Ariel H.; Gianechini, Federico A.; Garrido, Alberto C. (2023). "A rebbachisaurid-mimicking titanosaur and evidence of a Late Cretaceous faunal disturbance event in South-West Gondwana". Cretaceous Research. 154. doi:10.1016/j.cretres.2023.105754. ISSN   0195-6671.
  2. 1 2 Taylor, Michael P. (2022-01-24). "Almost all known sauropod necks are incomplete and distorted". PeerJ. 10: e12810. doi: 10.7717/peerj.12810 . ISSN   2167-8359. PMC   8793732 . PMID   35127288.
  3. Filippi, L. S.; Juárez Valieri, R. D.; Gallina, P. A.; Méndez, A. H.; Gianechini, F. A.; Garrido, A. C. (2016), "A new titanosaur specimen with highly derived skull from the Santonian of northern Patagonia, Argentina", 11 Congreso de la Asociación Paleontológica Argentina.
  4. Silva Junior, Julian C. G.; Marinho, Thiago S.; Martinelli, Agustín G.; Langer, Max C. (2019-04-08). "Osteology and systematics of Uberabatitan ribeiroi (Dinosauria; Sauropoda): a Late Cretaceous titanosaur from Minas Gerais, Brazil". Zootaxa. 4577 (3): 401. doi:10.11646/zootaxa.4577.3.1. eISSN   1175-5334. ISSN   1175-5326 . Retrieved 2021-02-13.
  5. Gorscak, Eric; O‘Connor, Patrick M. (2016-04-30). "Time-calibrated models support congruency between Cretaceous continental rifting and titanosaurian evolutionary history". Biology Letters. 12 (4): 20151047. doi: 10.1098/rsbl.2015.1047 . ISSN   1744-9561. PMC   4881341 . PMID   27048465.
  6. Gallina, Pablo A.; González Riga, Bernardo J.; Ortiz David, Leonardo D. (2022). "Time for Giants: Titanosaurs from the Berriasian–Santonian Age". South American Sauropodomorph Dinosaurs. Cham: Springer International Publishing. pp. 299–340. ISBN   978-3-030-95958-6.