Neuquensaurus

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Neuquensaurus
Temporal range: Late Cretaceous, 80  Ma
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Neuquensaurus skeleton mount.jpg
Neuquensaurus skeletal mount in the Dinosaurios más allá de la extinción exhibition
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
Family: Saltasauridae
Tribe: Saltasaurini
Genus: Neuquensaurus
Powell, 1992
Type species
Titanosaurus australis
Lydekker, 1893
Species
  • N. australis(Lydekker, 1893)
  • N. robustus(Huene, 1929 [originally Titanosaurus]) ( nomen dubium )
Synonyms
Genus synonymy
Species synonymy
  • Microcoelus patagonicus?
    Lydekker, 1893
  • Titanosaurus australis
    Lydekker, 1893
  • Titanosaurus nanus
    Lydekker, 1893
  • Titanosaurus robustus
    von Huene, 1929
  • Loricosaurus scutatus?
    von Huene, 1929
  • Saltasaurus australis
    (Lydekker, 1893 [originally Titanosaurus])
  • Saltasaurus robustus
    (von Huene, 1929 [originally Titanosaurus])

Neuquensaurus (meaning "Neuquén lizard") is a genus of saltasaurid sauropod dinosaur that lived in the Late Cretaceous, about 80 million years ago in Argentina in South America. Its fossils were recovered from outcrops of the Anacleto Formation around Cinco Saltos, near the Neuquén river from which its name is derived.

History

Holotypic caudal vertebrae Titanosaurus australis.jpg
Holotypic caudal vertebrae

In 1893, Richard Lydekker named Titanosaurus australis, based on a series of caudal vertebrae and limb elements. The remains had been found by Santiago Roth and F. Romero in the Neuquén Province of Argentina at the Neuquén River, and were by Lydekker assigned to a single individual. [1] Six caudal vertebrae, with the inventory numbers MLP Ly 1-6-V-28-1, were the holotype of the species. They had probably been found in a layer of the Anacleto Formation.

Some elements that had been referred to Titanosaurus australis were reassigned to Laplatasaurus araukanicus by Friedrich von Huene in 1929. [1] The same year, von Huene named a Titanosaurus robustus, and claimed it differed from T. australis in the limb material. Von Huene described all the slender limb material to T. australis, but did not identify any differentiating features between the vertebrae. [2] When describing T. robustus, von Huene did not really compare other genera and species to it. [1] From the syntype material assigned by von Huene to T. robustus José Fernando Bonaparte et al. in 1978 chose four lectotypes, specimens MLP 26-250, MLP 26-252, MLP 26-254, and MLP 26-259, a left femur, both ulnae, and a left radius. [3] [1]

In 1986, Jaime Eduardo Powell, concluding that Titanosaurus australis was less similar than Laplatasaurus araukanicus to Titanosaurus indicus, named a separate genus: Neuquensaurus. [4] However, he did so in an unpublished dissertation which caused Neuquensaurus australis and Neuquensaurus robustus to remain invalid nomina ex dissertatione. In 1990, the two species were assigned to Saltasaurus by John Stanton McIntosh, as a Saltasaurus australis and a Saltasaurus robustus, claiming that the features found by Bonaparte were not of sufficient taxonomic importance to justify a generic separation. [1]

In 1992 Powell validly named Neuquensaurus, with as type species Titanosaurus australis of which the combinatio nova then is Neuquensaurus australis. He also found Titanosaurus robustus to be assignable to the new genus, but considered it non-diagnostical, and so a nomen dubium . [5]

Description

Size comparison Neuquensaurus Scale.svg
Size comparison

This dinosaur is believed to have possessed armor-like osteoderms. A relatively small sauropod, with a femur only 0.75 metres (2.5 ft) long. It is one of the most completely known of Patagonian sauropods, [1] measuring 7–9 metres (23–30 ft) long and weighing 1.8–3.5 metric tons (2.0–3.9 short tons). [6] [7] In addition to the original fossils described by Lydekker in 1893, it is represented by fossils collected in the early twentieth century, and more recent material, including a well preserved and partially articulated specimen described in 2005 (with two associated osteoderms). [8]

Cervical vertebrae are known from multiple specimens of Neuquensaurus, although few are definitively associated with any other material. The centra are elongate, compressed vertically, and strongly opisthocoelous , with an ovoid pleurocoel and rounded neural spine. Diagnostic of Saltasaurinae, the prezygapophyses are shortened and robust and the postzygapophyses extend far posteriorly to compensate. The lateral projections of the neural arch (transverse processes) are far more robust than in Isisaurus . [8] As in the cervicals, the dorsal vertebrae bear strongly opisthocoelous centra with lateral pneumatic openings. In the dorsals, however, the pleurocoels are posteriorly pinched and internally subdivided, a regular feature of titanosaurs. The pleurocoels of Neuquensaurus are proportionally taller than in Trigonosaurus or Lirainosaurus . A ventral keel is lost throughout the dorsal series of probably 10 vertebrae, although the total count is uncertain. The vertebrae also lean less posteriorly towards the pelvis, initially inclined far beyond their individual centrum. However, they lack the hyposphene-hypantrum articulations of non-titanosaurs that limit vertebral motion. Two accessory laminae are present in the dorsals of Neuquensaurus that are absent even in the close relatives Saltasaurus and Rocasaurus . Unique among all sauropods, the sacrum of Neuquensaurus is composed of seven vertebrae. The last vertebra is convex anteriorly and posteriorly, and diagnostically the middle vertebrae are strongly compressed in width. [8] Like other derived titanosaurs, all caudal vertebrae of Neuquensaurus are strongly procoelous and vertically compressed. There is a prominent ventral depression like in Saltasaurus and Rocasaurus, but contrasting the other genera there is no ridge dividing this depression. Additionally, the neural spines of vertebrae become progressively more reclined, and a prespinal lamina is present in all vertebrae. [8]

Life restoration Neuquensaurus restoration.jpg
Life restoration

Neuquensaurus has an almost complete skeleton. Among the preserved elements are a scapula. The scapula is co-ossified with the coracoid, a feature also found in Opisthocoelicaudia . In general aspect, the scapula resembles Saltasaurus, Opisthocoelicaudia, Lirainosaurus , and Alamosaurus . The coracoids of the scapulae are roughly quadrangular in shape, and are alike Saltasaurus and Lirainosaurus, but not Opisthocoelicaudia, Rapetosaurus , or Isisaurus , all of which have a rounded coracoid. [1]

Many characters distinguish Neuquensaurus from other titanosaurians. The features found by Otero in 2010 are: the possession of posterior caudal centra that are dorsoventrally flattened, and strongly developed fibular lateral tuberosity. [1]

Classification

Neuquensaurus is a derived saltasaurine. Its closest relatives were Saltasaurus , Rocasaurus , and Bonatitan , and together they made up Saltasaurinae. [1]

Humerus and replica skull Neuquensaurus.jpg
Humerus and replica skull
Restored skeleton of N. australis Neuquensaurus australis.jpg
Restored skeleton of N. australis

The cladogram from Rubilar-Rogers et al. (2021) is shown below: [9]

Lithostrotia


Paleoecology

Neuquensaurus is known from fossils from the Anacleto Formation. [1]

Related Research Articles

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

Saltasaurus is a genus of saltasaurid dinosaur of the Late Cretaceous period of Argentina. Small among sauropods, though still heavy by the standards of modern creatures, Saltasaurus was characterized by a short neck and stubby limbs. It was the first genus of sauropod known to possess armour of bony plates embedded in its skin. Such small bony plates, called osteoderms, have since been found on other titanosaurians.

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

Titanosaurs were a diverse group of sauropod dinosaurs, including genera from all seven continents. The titanosaurs were the last surviving group of long-necked sauropods, with taxa still thriving at the time of the extinction event at the end of the Cretaceous. This group includes some of the largest land animals known to have ever existed, such as Patagotitan—estimated at 37 m (121 ft) long with a weight of 69 tonnes —and the comparably-sized Argentinosaurus and Puertasaurus from the same region.

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

Titanosaurus is a dubious genus of sauropod dinosaurs, first described by Richard Lydekker in 1877. It is known from the Maastrichtian Lameta Formation of India.

<i>Argyrosaurus</i> Genus of herbivorous titanosaurian sauropod dinosaur

Argyrosaurus is a genus of titanosaurian sauropod dinosaur that lived about 70 million years ago, during the Late Cretaceous Period of what is now Argentina.

<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>Opisthocoelicaudia</i> Sauropod dinosaur genus from Late Cretaceous Mongolia

Opisthocoelicaudia is a genus of sauropod dinosaur of the Late Cretaceous Period discovered in the Gobi Desert of Mongolia. The type species is Opisthocoelicaudia skarzynskii. A well-preserved skeleton lacking only the head and neck was unearthed in 1965 by Polish and Mongolian scientists, making Opisthocoelicaudia one of the best known sauropods from the Late Cretaceous. Tooth marks on this skeleton indicate that large carnivorous dinosaurs had fed on the carcass and possibly had carried away the now-missing parts. To date, only two additional, much less complete specimens are known, including part of a shoulder and a fragmentary tail. A relatively small sauropod, Opisthocoelicaudia measured about 11.4–13 m (37–43 ft) in length. Like other sauropods, it would have been characterised by a small head sitting on a very long neck and a barrel shaped trunk carried by four column-like legs. The name Opisthocoelicaudia means "posterior cavity tail", alluding to the unusual, opisthocoel condition of the anterior tail vertebrae that were concave on their posterior sides. This and other skeletal features lead researchers to propose that Opisthocoelicaudia was able to rear on its hindlegs.

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

Andesaurus is a genus of basal titanosaurian sauropod dinosaur which existed during the middle of the Cretaceous Period in South America. Like most sauropods, belonging to one of the largest animals ever to walk the Earth, it would have had a small head on the end of a long neck and an equally long tail.

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

Laplatasaurus is a genus of titanosaurian sauropod dinosaur that lived during the Late Cretaceous in South America, with the holotype and only known specimen found in the Anacleto Formation.

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

Huabeisaurus was a genus of dinosaur from the Late Cretaceous. It was a sauropod which lived in what is present-day northern China. The type species, Huabeisaurus allocotus, was first described by Pang Qiqing and Cheng Zhengwu in 2000. Huabeisaurus is known from numerous remains found in the 1990s, which include teeth, partial limbs and vertebrae. Due to its relative completeness, Huabeisaurus represents a significant taxon for understanding sauropod evolution in Asia. Huabeisaurus comes from Kangdailiang and Houyu, Zhaojiagou Town, Tianzhen County, Shanxi province, China. The holotype was found in the unnamed upper member of the Huiquanpu Formation, which is Late Cretaceous (?Cenomanian–?Campanian) in age based on ostracods, charophytes, and fission-track dating.

Venenosaurus is a genus of sauropod dinosaur that lived in what is now Utah during the Early Cretaceous. Its type and only species is Venenosaurus dicrocei. Fossils of Venenosaurus were first discovered in 1998, by Denver Museum of Natural History volunteer Anthony DiCroce, and described as a new genus and species in 2001 by Virginia Tidwell and colleagues, who named the species for DiCroce. Venenosaurus was a relatively small sauropod, and was similar to Cedarosaurus, another sauropod from the Early Cretaceous of Utah.

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

Lirainosaurus is a genus of titanosaur sauropod which lived in what is now Spain. The type species, Lirainosaurus astibiae, was described by Sanz, Powell, Le Loeuff, Martinez, and Pereda-Suberbiola in 1999. It was a relatively small sauropod, measuring 4 metres (13 ft) long, possibly up to 6 metres (20 ft) long for the largest individuals, and weighed about 2–4 metric tons.

<i>Rocasaurus</i> Genus of titanosaurian sauropod from the Late Cretaceous period

Rocasaurus is a genus of titanosaurian sauropod that lived in South America. Rocasaurus was discovered in Argentina in 2000, within the Allen Formation which is dated to be middle Campanian to early Maastrichtian in age. This genus grew up to 8 metres (26 ft) long, making it one of the smaller sauropods. It seems to be closely related to saltasaurid dinosaurs, like Saltasaurus and Neuquensaurus.

<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.

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

Saltasauridae is a family of armored herbivorous sauropods from the Upper Cretaceous. They are known from fossils found in South America, Africa, Asia, North America, and Europe. They are characterized by their vertebrae and feet, which are similar to those of Saltasaurus, the first of the group to be discovered and the source of the name. The last and largest of the group and only one found in North America, Alamosaurus, was thirty-four metres in length and one of the last sauropods to go extinct.

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

Diamantinasaurus is a genus of titanosaurian sauropod from Australia that lived during the early Late Cretaceous, about 94 million years ago. The type species of the genus is D. matildae, first described and named in 2009 by Scott Hocknull and colleagues based on fossil finds in the Winton Formation. Meaning "Diamantina lizard", the name is derived from the location of the nearby Diamantina River and the Greek word sauros, "lizard". The specific epithet is from the Australian song Waltzing Matilda, also the locality of the holotype and paratype. The known skeleton includes most of the forelimb, shoulder girdle, pelvis, hindlimb and ribs of the holotype, and one shoulder bone, a radius and some vertebrae of the paratype.

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

Atacamatitan is a genus of titanosaurian sauropod dinosaurs from the Late Cretaceous Tolar Formation of Chile.

<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.

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

Saltasaurinae is a subfamily of titanosaurian sauropods known from the late Cretaceous period of South America, India and Madagascar.

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

Patagotitan is a genus of titanosaurian sauropod dinosaur from the Cerro Barcino Formation in Chubut Province, Patagonia, Argentina. The genus contains a single species known from at least six young adult individuals, Patagotitan mayorum, which was first announced in 2014 and then named in 2017 by José Carballido and colleagues. Preliminary studies and press releases suggested that Patagotitan was the largest known titanosaur and land animal overall, with an estimated length of 37 m (121 ft) and an estimated weight of 69 tonnes. Later research revised the length estimate down to 31 m (102 ft) and weight estimates down to approximately 50–57 tonnes, suggesting that Patagotitan was of a similar size to, if not smaller than, its closest relatives Argentinosaurus and Puertasaurus. Still, Patagotitan is one of the most-known titanosaurs, and so its interrelationships with other titanosaurs have been relatively consistent in phylogenetic analyses. This led to its use in a re-definition of the group Colossosauria by Carballido and colleagues in 2022.

<span class="mw-page-title-main">Saltasaurini</span> Extinct tribe of reptiles

Saltasaurini is a tribe of titanosaur sauropods known from the Late Cretaceous of Patagonia, Argentina. The clade was named in 2007 by Leonardo Salgado and José Bonaparte as the "least inclusive clade comprising Neuquensaurus and Saltasaurus", which is equivalent to the use of Saltasaurinae in Salgado et al. (1997). Found only in the Campanian to Maastrichtian sediments of the Neuquén Basin, Salgado & Bonaparte (2007) decided a more restrictive clade was needed because of the expansion of Saltasaurinae as defined to include far more taxa than it originally encompassed. Saltasaurini includes the original core of Saltasaurinae: Neuquensaurus, Saltasaurus, Rocasaurus and Bonatitan, although some studies exclude Bonatitan from the clade.

References

  1. 1 2 3 4 5 6 7 8 9 10 Alejandro Otero (2010). "The appendicular skeleton of Neuquensaurus, a Late Cretaceous saltasaurine sauropod from Patagonia, Argentina" (PDF). Acta Palaeontologica Polonica. 55 (3): 399–426. doi: 10.4202/app.2009.0099 .
  2. F. v. Huene, 1929, "Los sauriquios y ornitisquios del Cretáceo argentino", Anales del Museo de La Plata, serie 23: 1-196
  3. Bonaparte, J.F. and Gasparini, Z., 1978, "The sauropods of the Neuquén and Chubut Groups and their chronological relations", VII Congreso Geologico Argentino, Neuquén 11 pp 393–406
  4. Powell, J.E., 1986, Revisión del titanosáuridos de América del Sur, dissertation Universidad Nacional de Tucumán
  5. J.E. Powell, 1992, "Osteologia de Saltasaurus loricatus (Sauropoda - Titanosauridae) del Cretácico Superior del noroeste Argentino" In: J.L. Sanz & A.D. Buscalioni (eds.), Los Dinosaurios y Su Entorno Biotico: Actas del Segundo Curso de Paleontologia in Cuenca. Institutio "Juan de Valdes", Cuenca, Argentina pp 165-230
  6. Paul, Gregory S. (2016). The Princeton Field Guide to Dinosaurs 2nd edition. Oxford: Princeton University Press. p. 238. ISBN   9780691167664.
  7. Stein, K.; Csiki, Z.; Curry Rogers, K.; Weishampel, D.B.; Redelstorff, R.; Carballidoa, J.L.; Sander, P.M. (2010). "Small body size and extreme cortical bone remodeling indicate phyletic dwarfism in Magyarosaurus dacus (Sauropoda: Titanosauria)". Proceedings of the National Academy of Sciences of the United States of America. 20. 107 (20): 9258–9263. Bibcode:2010PNAS..107.9258S. doi: 10.1073/pnas.1000781107 . PMC   2889090 . PMID   20435913.
  8. 1 2 3 4 Salgado, L.; Apesteguía, S.; Heredia, S.E. (2005). "A New Specimen of Neuquensaurus australis, a Late Cretaceous Saltasaurine Titanosaur from North Patagonia". Journal of Vertebrate Paleontology. 25 (3): 623–634. doi:10.1671/0272-4634(2005)025[0623:ANSONA]2.0.CO;2. JSTOR   4524482.
  9. Rubilar-Rogers, D.; Vargas, A. O.; González Riga, B.; Soto-Acuña, S.; Alarcón-Muñoz, J.; Iriarte-Díaz, J.; Arévalo, C.; Gutstein, C. S. (2021). "Arackar licanantay gen. et sp. nov. a new lithostrotian (Dinosauria, Sauropoda) from the Upper Cretaceous of the Atacama Region, northern Chile". Cretaceous Research. 124: Article 104802. Bibcode:2021CrRes.12404802R. doi:10.1016/j.cretres.2021.104802. S2CID   233780252.