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. robustusJosé Fernando Bonaparteet 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Laplatasaurus araukanicus to Titanosaurus indicus, named a separate genus: Neuquensaurus.[4] However, he did so in an unpublished dissertation which caused Neuquensaurus australis and Neuquensaurus robustus to remain invalid nomina ex dissertatione.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 speciesTitanosaurus 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]
DescriptionEdit
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]
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]
^ abcdefghijAlejandro 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.
^F. v. Huene, 1929, "Los sauriquios y ornitisquios del Cretáceo argentino", Anales del Museo de La Plata, serie 23: 1-196
^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
^Powell, J.E., 1986, Revisión del titanosáuridos de América del Sur, dissertation Universidad Nacional de Tucumán
^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
^Paul, Gregory S. (2016). The Princeton Field Guide to Dinosaurs 2nd edition. Oxford: Princeton University Press. p. 238. ISBN9780691167664.
^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. PMC2889090. PMID 20435913.
^ abcdSalgado, 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. JSTOR 4524482.
^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. doi:10.1016/j.cretres.2021.104802. S2CID 233780252.
External linksEdit
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neuquensaurus, meaning, neuquén, lizard, genus, saltasaurid, sauropod, dinosaur, that, lived, late, cretaceous, about, million, years, argentina, south, america, fossils, were, recovered, from, outcrops, anacleto, formation, around, cinco, saltos, near, neuqué. Neuquensaurus meaning Neuquen 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 Neuquen river from which its name is derived NeuquensaurusTemporal range Late Cretaceous 80 Ma PreꞒ Ꞓ O S D C P T J K Pg N Neuquensaurus skeletal mount in the Dinosaurios mas alla de la extincion exhibitionScientific classificationDomain EukaryotaKingdom AnimaliaPhylum ChordataClade DinosauriaClade SaurischiaClade SauropodomorphaClade SauropodaClade MacronariaClade TitanosauriaClade LithostrotiaFamily SaltasauridaeTribe SaltasauriniGenus NeuquensaurusPowell 1992Type species Titanosaurus australisLydekker 1893Species N australis Lydekker 1893 N robustus Huene 1929 originally Titanosaurus nomen dubium SynonymsGenus synonymy Microcoelus Lydekker 1893Loricosaurus von Huene 1929 Species synonymy Microcoelus patagonicus Lydekker 1893Titanosaurus australis Lydekker 1893Titanosaurus nanus Lydekker 1893Titanosaurus robustus von Huene 1929Loricosaurus scutatus von Huene 1929Saltasaurus australis Lydekker 1893 originally Titanosaurus Saltasaurus robustus von Huene 1929 originally Titanosaurus Contents 1 History 2 Description 3 Classification 4 Paleoecology 5 References 6 External linksHistory Edit nbsp Holotypic caudal vertebraeIn 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 Neuquen Province of Argentina at the Neuquen 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 Jose 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 Edit nbsp Size comparisonThis 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 nbsp Life restorationNeuquensaurus 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 EditNeuquensaurus is a derived saltasaurine Its closest relatives were Saltasaurus Rocasaurus and Bonatitan and together they made up Saltasaurinae 1 nbsp Humerus and replica skull nbsp Restored skeleton of N australisThe cladogram from Rubilar Rogers et al 2021 is shown below 9 Lithostrotia MalawisaurusBaurutitanRapetosaurusArackarIsisaurusTapuiasaurusAlamosaurusOpisthocoelicaudiaNeuquensaurusSaltasaurusPaleoecology EditNeuquensaurus is known from fossils from the Anacleto Formation 1 References Edit a b c d e f g h i j 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 F v Huene 1929 Los sauriquios y ornitisquios del Cretaceo argentino Anales del Museo de La Plata serie 2 3 1 196 Bonaparte J F and Gasparini Z 1978 The sauropods of the Neuquen and Chubut Groups and their chronological relations VII Congreso Geologico Argentino Neuquen 11 pp 393 406 Powell J E 1986 Revision del titanosauridos de America del Sur dissertation Universidad Nacional de Tucuman J E Powell 1992 Osteologia de Saltasaurus loricatus Sauropoda Titanosauridae del Cretacico Superior del noroeste Argentino In J L Sanz amp 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 Paul Gregory S 2016 The Princeton Field Guide to Dinosaurs 2nd edition Oxford Princeton University Press p 238 ISBN 9780691167664 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 a b c d Salgado L Apesteguia 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 JSTOR 4524482 Rubilar Rogers D Vargas A O Gonzalez Riga B Soto Acuna S Alarcon Munoz J Iriarte Diaz J Arevalo 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 doi 10 1016 j cretres 2021 104802 S2CID 233780252 External links Edit nbsp Wikimedia Commons has media related to Neuquensaurus nbsp Cretaceous portal nbsp Dinosaurs portal nbsp Paleontology portal Retrieved from https en wikipedia org w index php title Neuquensaurus amp oldid 1175268425, wikipedia, wiki, book, books, library,
