Argentinadraco

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Argentinadraco
Temporal range: Turonian-Coniacian
~91–88  Ma
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Argentinadraco jaw.jpg
The holotype lower jaw
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Order:† Pterosauria
Suborder:† Pterodactyloidea
Clade:† Azhdarchoidea
Genus:† Argentinadraco
Kellner & Calvo 2017
Type species
†Argentinadraco barrealensis
Kellner & Calvo 2017

Argentinadraco (meaning "Argentina dragon") is an extinct genus of azhdarchoid pterosaur from the Late Cretaceous Portezuelo Formation of Argentina. It contains a single species, A. barrealensis, named in 2017 by Alexander Kellner and Jorge Calvo. Argentinadraco is unusual for bearing a bottom jaw with a concave bottom edge, as well as a pair of ridges and depressions on the top surface. These features distinguish it from all other azhdarchoid groups, complicating its assignment, but it may belong to the Chaoyangopteridae. The ridges on the lower jaw may have been used to feed on small invertebrates in loose sediment within the system of lakes and rivers that it resided in.

Contents

Discovery and naming

Map showing the location of the Futalognko quarry Futalognko site map.jpg
Map showing the location of the Futalognko quarry

Argentinadraco is known from a single partial lower jaw, missing the rear end. The specimen is also compressed, especially near the tip of the jaw. Catalogued as MUCPv-1137 in the Centro Paleontológico Lago Barreales (CePaLB) of the National University of Comahue, it was found in layers of yellow sandstone and red/green claystone within the Futalognko quarry, which is located on the northern shore of Lake Barreales. The quarry is 90 km (56 mi) northwest of Neuquén, in Neuquén Province, Patagonia, Argentina. Exposed deposits at the site belong to the Portezuelo Formation, a part of the Neuquén Group of the Neuquén Basin, that dates to the Turonian or Coniacian epochs of the Cretaceous period. [1] [2]

Alexander Kellner, Jorge Calvo, Juan Porfiri, and Domenica dos Santos briefly described the specimen in an abstract at the 2011 Fourth Latin American Congress of Vertebrate Paleontology. [3] Kellner and Calvo would go on to describe and name the specimen formally in 2017. The genus name Argentinadraco is derived from Argentina plus the suffix -draco, from the Latin word for "dragon", while the species name barrealensis is a reference to the locality of Lake Barreales. [1]

Description

A closer view of the ridges and depressions at the back of the preserved jaw Argentinadraco jaw posterodorsal inset.jpg
A closer view of the ridges and depressions at the back of the preserved jaw

The size of Argentinadraco is difficult to estimate, but the preserved segment of the lower jaw measures 259 mm (10.2 in) long. The symphysis of the lower jaw was likely long, taking up some 50% of the jaw's total length in life. The external cortical bone is thin, and the bones of the jaw are thoroughly fused, which characterizes Argentinadraco as a relatively derived (specialized) pterosaur. [1]

While the top margin of the lower jaw is straight, like members of the Azhdarchidae, [4] [5] the bottom margin of the symphysis is deep (44 mm (1.7 in) tall) at the rear but becomes shallower in front, making it markedly concave. This sets Argentinadraco apart from other members of the Azhdarchoidea. The entire bottom margin is blunt and thickened. There is also, unusually, a small crest along the concave portion of the bottom margin, but it is not as developed as the crests of the Tapejaridae. [1]

The top surface of the symphysis is bordered by blunt outer margins (unlike the sharp margins of Thalassodromeus [6] [7] ), separated by a narrow depression. This depression becomes a concave shelf at the back of the jaw, and it is unusually flanked by a pair of well-developed ridges inset from the actual outer margins. The ridges are separated from the outer margins by narrow depressions. Most other toothless pterosaurs have a simple flattened or concave surface. There is a shallow pit, or fossa, at the back of the symphysis, caused by it ending in two segments as in Caupedactylus and Quetzalcoatlus . [1] [4] [8]

Classification

Although being toothless clearly places Argentinadraco in the Dsungaripteroidea sensu Kellner, more specifically within the Azhdarchoidea, its precise classification within this group is more elusive. Lower jaws of the Thalassodrominae, Chaoyangopteridae, and Azhdarchidae tend to be either very similar or radically divergent within the same group. The proportions of at least the front portion of the lower jaw of Argentinadraco resembles those of the azhdarchid Zhejiangopterus , and the chaoyangopterids Chaoyangopterus and Shenzhoupterus . [1]

Argentinadraco bears differences, however, from all three groups. Its jaw is more robust and shorter than those of Quetzalcoatlus and some other azhdarchids. The deep rear end and the blunt ridges on the top surface also separate it from thalassodromines and chaoyangopterids. While the thalassodromine Tupuxuara has a crest on the bottom margin of its jaw, [9] it does not have the shallow depression on the top surface. Kellner and Calvo tentatively assigned Argentinadraco to the Azhdarchidae based on provenance. It may instead represent an entirely new group, but this is difficult to test. [1]

Nevertheless, Argentinadraco can be confidently excluded from the Pteranodontidae, Nyctosauridae, and Tapejarinae, the other groups of toothless dsungaripteroid pterosaurs. The back of the symphysis in Argentinadraco is deep like the pteranodontids, but the deepest point is further forward; the shelf of the symphysis is also inclined downwards instead of being arched as in pteranodontids, and the two-segment ending of the symphysis is not known in pteranodontids either. Nyctosaurids have an additional shelf on the symphysis, and the top margin of the lower jaw curves upwards. [10] Finally, Argentinadraco does not have a downturned lower jaw, a step-like upper margin, or a deep crest, which all characterize tapejarines, [9] [11] [12] [13] and its jaw is much less robust. [1]

A study describing Javelinadactylus (now Wellnhopterus ) recovered Argentinadraco as a closely related thalassodromine. The study has since been retracted. [14] Conversely, a study focused on Aerotitan recovers it as a chaoyangopterid closely related to Xericeps . [15]

Paleobiology

Life reconstruction Argentinadraco.jpg
Life reconstruction

The unusually elaborate combination of ridges and depressions on the top surface of the lower jaw in Argentinadraco suggests that the lower jaw interlocked with the upper jaw in some way. Meanwhile, as has been inferred for Pteranodon , [16] the depth of the rear of the symphysis suggests that it had strong bite forces. Kellner and Calvo speculatively suggested that Argentinadraco used its peculiar jaw to slice through loose sediment in the rivers or lakes of its environment, potentially feeding on small invertebrates such as crustaceans. They interpreted such a lifestyle as being consistent with the terrestrial feeding habits of azhdarchids. [1]

Paleoecology

A diverse assemblage of animals has been recovered from the Futalognko quarry, which represents a continental deposit. It was deposited in a humid environment, and represents a system of meandering rivers. [17] Argentinadraco in particular was probably preserved after being trapped on a point bar by low-energy water flow. Pterosaurs are rare in the Futalognko quarry, but remains (including an ulna) have previously been assigned to the Azhdarchidae. [18] [19] Dinosaurs include the theropods Megaraptor [20] and Unenlagia [21] (alongside dromaeosaurid and carcharodontosaurid teeth), the sauropod Futalognkosaurus , [22] and indeterminate iguanodontian ornithopods. [1] [23]

Additionally, a crocodylomorph similar to Comahuesuchus is also known from Futalognko, as are teeth of the Peirosauridae. [24] Turtles of the group Pelomedusoidea have been found as well. Fish include a small member of the Euteleostei, two members of the Clupeomorpha, and a member of the Semionotidae, known from scales. Freshwater bivalves have also been found at Futalognko. Finally, plant fossils are dominated by angiosperms, specifically dicotyledons, but leaves and fruiting bodies from gymnosperms are also known alongside conifers. [1] [23] [25]

See also

Related Research Articles

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

Megaraptor is a genus of large theropod dinosaur that lived in the ages of the Late Cretaceous. Its fossils have been discovered in the Patagonian Portezuelo Formation of Argentina, South America. Initially thought to have been a giant dromaeosaur-like coelurosaur, it was classified as a neovenatorid allosauroid in previous phylogenies, but more recent phylogeny and discoveries of related megaraptoran genera has placed it as either a basal tyrannosauroid or a basal coelurosaur with some studies still considering it a neovenatorid.

Unenlagia is a genus of dromaeosaurid theropod dinosaur that lived in South America during the Late Cretaceous period. The genus Unenlagia has been assigned two species: U. comahuensis, the type species described by Novas and Puerta in 1997, and U. paynemili, described by Calvo et al. in 2004.

<span class="mw-page-title-main">Azhdarchidae</span> Family of large azhdarchoid pterosaurs

Azhdarchidae is a family of pterosaurs known primarily from the Late Cretaceous Period, though an isolated vertebra apparently from an azhdarchid is known from the Early Cretaceous as well. Azhdarchids are mainly known for including some of the largest flying animals discovered, but smaller cat-size members have also been found. Originally considered a sub-family of Pteranodontidae, Nesov (1984) named the Azhdarchinae to include the pterosaurs Azhdarcho, Quetzalcoatlus, and Titanopteryx. They were among the last known surviving members of the pterosaurs, and were a rather successful group with a worldwide distribution. Previously it was thought that by the end of the Cretaceous, most pterosaur families except for the Azhdarchidae disappeared from the fossil record, but recent studies indicate a wealth of pterosaurian fauna, including pteranodontids, nyctosaurids, tapejarids and several indeterminate forms. In several analyses, some taxa such as Navajodactylus, Bakonydraco and Montanazhdarcho were moved from Azhdarchidae to other clades.

<i>Thalassodromeus</i> Genus of azhdarchoid pterosaur from the Early Cretaceous

Thalassodromeus is a genus of pterosaur that lived in what is now Brazil during the Early Cretaceous period, about a hundred million years ago. The original skull, discovered in 1983 in the Araripe Basin of northeastern Brazil, was collected in several pieces. In 2002, the skull was made the holotype specimen of Thalassodromeus sethi by palaeontologists Alexander Kellner and Diogenes de Almeida Campos. The generic name means "sea runner", and the specific name refers to the Egyptian god Seth due to its crest being supposedly reminiscent of Seth's crown. Other scholars have pointed out that the crest was instead similar to the crown of Amon. A jaw tip was assigned to T. sethi in 2005, became the basis of the new genus Banguela in 2015, and assigned back to Thalassodromeus as the species T. oberlii in 2018, though other researchers claim that Banguela is a valid genus. Another species was described in 2015 based on a supposed crest fragment, but this was later shown to be part of a turtle shell.

<span class="mw-page-title-main">Tapejaridae</span> Family of azhdarchoid pterosaurs from the Cretaceous period

Tapejaridae are a family of pterodactyloid pterosaurs from the Cretaceous period. Members are currently known from Brazil, England, Hungary, Morocco, Spain, the United States, and China. The most primitive genera were found in China, indicating that the family has an Asian origin.

<i>Eopteranodon</i> Genus of tapejarid pterosaur

Eopteranodon is a genus of tapejarid pterosaur from the Aptian-age Lower Cretaceous Yixian Formation of Beipiao City, Liaoning, China. The genus was named in 2005 by paleontologists Lü Junchang and Zhang Xingliao. The type species is Eopteranodon lii.

<i>Jidapterus</i> Genus of chaoyangopterid pterosaur from the Early Cretaceous

Jidapterus is a genus of chaoyangopterid pterosaur from the Aptian-age Lower Cretaceous Jiufotang Formation of Chaoyang, Liaoning, China. The genus was in 2003 named by Dong Zhiming, Sun Yue-Wu and Wu Shao-Yuan. The type species is Jidapterus edentus. The genus name is derived from Jílín Dàxué or "Jilin University" and a Latinized Greek pteron, "wing". The specific name means "toothless" in Latin.

<span class="mw-page-title-main">Azhdarchoidea</span> Superfamily of ornithocheiroid pterosaurs

Azhdarchoidea is a group of pterosaurs within the suborder Pterodactyloidea, more specifically within the group Ornithocheiroidea. Pterosaurs belonging to this group lived throughout the Early and Late Cretaceous periods, with one tentative member, Tendaguripterus, that lived in the Late Jurassic period. The largest azhdarchoids include members of the family Azhdarchidae, examples of these are Quetzalcoatlus, Hatzegopteryx, and Arambourgiania. The Azhdarchoidea has been recovered as either closely related to the Ctenochasmatoidea, as the sister taxon of the Pteranodontoidea within the Ornithocheiroidea, or within the Tapejaroidea, which in turn was also within the Ornithocheiroidea.

<span class="mw-page-title-main">Chaoyangopteridae</span> Family of azhdarchoid pterosaurs

Chaoyangopteridae is a family of pterosaurs within the larger group Azhdarchoidea. Chaoyangopterids lived mostly during the Early Cretaceous period, though possible members, Microtuban, Xericeps and Argentinadraco, may extend the fossil range to the Late Cretaceous.

<span class="mw-page-title-main">Thalassodrominae</span> Subfamily of azhdarchoid pterosaurs from the Cretaceous period

Thalassodrominae or Thalassodromidae is a group of azhdarchoid pterosaurs from the Cretaceous period. Its traditional members come from Brazil, however, other possible members also come from other places, including the United States, Morocco, and Argentina. Thalassodrominae is considered either to be a subfamily within the pterosaur family Tapejaridae, or as a distinct family, Thalassodromidae, within the clade Neoazhdarchia, closely related to dsungaripterids or azhdarchids.

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

Pamparaptor is an extinct genus of maniraptoran theropod dinosaur from the Late Cretaceous Portezuelo Formation of the Neuquén province in Argentine Patagonia. Its precise classification is uncertain, but it is definitely a member of Paraves and probably a deinonychosaur. The authors who described it have argued that it is a dromaeosaurid. The genus contains a single species, P. micros, which is known from a single specimen consisting of a mostly complete and fully-articulated left foot, which preserves the iconic dromaeosaur-like "killing claw".

<span class="mw-page-title-main">Dsungaripteridae</span> Family of ornithocheiroid pterosaurs

Dsungaripteridae is a group of pterosaurs within the suborder Pterodactyloidea. They were robust pterosaurs with good terrestrial abilities and flight honed for inland settings, and were commonly interpreted as durophagous and possibly piscivorous pterosaurs. Fossils have been discovered from Early Cretaceous deposits in Asia, South America and possibly Europe.

<i>Aerotitan</i> Genus of azhdarchid pterosaur from the Late Cretaceous

Aerotitan is a genus of large azhdarchid pterosaur known from the Late Cretaceous period of what is now the Allen Formation of the Neuquén Basin in northern Patagonia, Argentina.

<i>Caupedactylus</i> Genus of tapejarid pterosaur form the Early Cretaceous

Caupedactylus is an extinct genus of tapejarid azhdarchoid pterosaur known from the Early Cretaceous period of what is now the Romualdo Formation of the Araripe Basin in northeastern Brazil. The type and only species of Caupedactylus is Caupedactylus ybaka.

<i>Banguela</i> Genus of azhdarchoid pterosaur from the Early Cretaceous

Banguela is a genus of azhdarchoid pterosaur from the Early Cretaceous period of what is now Brazil. Only one species is known, Banguela oberlii.

<span class="mw-page-title-main">Tapejaroidea</span> Clade of ornithocheiroid pterosaurs

Tapejaroidea is a group of pterosaurs belonging to the clade Ornithocheiroidea. Tapejaroids lived from the Early to Late Cretaceous periods, with one possible member, Tendaguripterus, extending the fossil range to the Late Jurassic period. Tapejaroidea contains two groups, the Dsungaripteridae and the Azhdarchoidea, which in turn includes the azhdarchids, the group that contains some of the largest flying animals. The group was named by Brazilian paleontologist Alexander Wilhelm Armin Kellner in 1996.

<i>Aymberedactylus</i> Genus of tapejarid pterosaur from the Early Cretaceous

Aymberedactylus is a genus of tapejarid pterosaur from the Early Cretaceous Crato Formation of Brazil. It contains a single species, A. cearensis.

<i>Apatorhamphus</i> Genus of azhdarchoid pterosaur from the Late Cretaceous

Apatorhamphus is an extinct genus of azhdarchoid pterosaur from the Kem Kem Group of Morocco. It might have been part of the Chaoyangopteridae. It is only known from a few snout fragments and it likely had a wingspan of between 3–7 metres (9.8–23.0 ft)

<i>Wellnhopterus</i> Genus of azhdarchid pterosaur from the Late Cretaceous

Wellnhopterus is an azhdarchid pterosaur recovered from the Late Cretaceous Javelina Formation in Texas that was previously identified as a thalassodromine. It consists of a set of upper and lower jaws, as well as some cervical vertebrae and a fragmentary long bone. In July 2021, the jaws were given the genus name "Javelinadactylus", with the type and only species as "J. sagebieli"; however, this article has now been retracted. In a paper published in December 2021, the complete holotype was independently named Wellnhopterus, with the only species being W. brevirostris. As of 2022, this is the formal name of this pterosaur.

References

  1. 1 2 3 4 5 6 7 8 9 10 11 Kellner, A.W.A.; Calvo, J.O. (2017). "New azhdarchoid pterosaur (Pterosauria, Pterodactyloidea) with an unusual lower jaw from the Portezuelo Formation (Upper Cretaceous), Neuquén Group, Patagonia, Argentina". Anais da Academia Brasileira de Ciências. 89 (3 Suppl): 2003–2012. doi: 10.1590/0001-3765201720170478 . ISSN   1678-2690. PMID   29166530.
  2. ↑ Leanza, H.A.; Hugo, C.A. (2001). "Cretaceous red beds from southern Neuquén Basin (Argentina): age, distribution and stratigraphic discontinuities". In Leanza, H.A. (ed.). Abstracts. International Symposium on Mesozoic Terrestrial Ecosystems. Vol. 7. Buenos Aires: Asociación Paleontológica Argentina. pp. 117–122.
  3. ↑ Kellner, A.W.A.; Calvo, J.O.; Porfiri, J.D.; Dos Santos, D. (2011). An Azharchoid lower jaw (Pterosauria, Pterodactyloidea) from the Portezuelo Formation (Cretaceous), Neuquén Group, Patagonia, Argentina. IV Congreso Latinoamericano de Paleontologia de Vertebrados. San Juan.
  4. 1 2 Kellner, A.W.A.; Langston, W. (1996). "Cranial remains of Quetzalcoatlus (Pterosauria, Azhdarchidae) from Late Cretaceous sediments of Big Bend National Park, Texas". Journal of Vertebrate Paleontology. 16 (2): 222–231. Bibcode:1996JVPal..16..222K. doi:10.1080/02724634.1996.10011310.
  5. ↑ Cai, Z.; Wei, F. (1994). "On a new pterosaur (Zhejiangopterus linhaiensis gen. et sp. nov.) from Upper Cretaceous in Linhai, Zhejiang, China" (PDF). Vertebrata PalAsiatica. 32 (3): 181–194.
  6. ↑ Kellner, A.W.A.; Campos, D.A. (July 19, 2002). "The function of the cranial crest and jaws of a unique pterosaur from the early Cretaceous of Brazil" (PDF). Science. 297 (5580): 389–392. Bibcode:2002Sci...297..389K. doi:10.1126/science.1073186. PMID   12130783. S2CID   45430990.
  7. ↑ Kellner, A.W.A.; Campos, D.A. (2007). "Short note on the ingroup relationships of the Tapejaridae (Pterosauria, Pterodactyloidea)". Boletim do Museu Nacional. 75: 1–14.
  8. ↑ Kellner, A.W.A. (2013). "A new unusual tapejarid (Pterosauria, Pterodactyloidea) from the Early Cretaceous Romualdo Formation, Araripe Basin, Brazil". Earth and Environmental Science Transactions of the Royal Society of Edinburgh. 103 (3–4): 409–421. Bibcode:2013EESTR.103..409K. doi:10.1017/S1755691013000327. S2CID   131574480.
  9. 1 2 Kellner, A.W.A. (2004). "New information on the Tapejaridae (Pterosauria, Pterodactyloidea) and discussion of the relationships of this clade". Ameghiniana. 41 (4): 521–534. ISSN   0002-7014.
  10. ↑ Bennett, S.C. (2003). "New crested specimens of the Late Cretaceous pterosaur Nyctosaurus". Paläontologische Zeitschrift. 77 (1): 61–75. Bibcode:2003PalZ...77...61B. doi:10.1007/bf03004560. S2CID   129438441.
  11. ↑ Pinheiro, F.L.; Fortier, D.C.; Schultz, C.L.; De Andrade, J.A.F.G.; Bantim, R.A.M. (2011). "New information on Tupandactylus imperator, with comments on the relationships of Tapejaridae (Pterosauria)". Acta Palaeontologica Polonica. 56 (3): 567–580. doi: 10.4202/app.2010.0057 .
  12. ↑ Vullo, R.; Marugán-Lobón, J.S.; Kellner, A.W.A.; Buscalioni, A.D.; Gomez, B.; De La Fuente, M.; Moratalla, J.J. (2012). "A New Crested Pterosaur from the Early Cretaceous of Spain: The First European Tapejarid (Pterodactyloidea: Azhdarchoidea)". PLOS ONE. 7 (7): e38900. Bibcode:2012PLoSO...738900V. doi: 10.1371/journal.pone.0038900 . PMC   3389002 . PMID   22802931.
  13. ↑ Manzig, P.C.; Kellner, A.W.A.; Weinschütz, L.C.; Fragoso, C.E.; Vega, C.S.; Guimarães, G.B.; Godoy, L.C.; Liccardo, A.; Ricetti, J.H.C.; Moura, C.C. (2014). "Discovery of a Rare Pterosaur Bone Bed in a Cretaceous Desert with Insights on Ontogeny and Behavior of Flying Reptiles". PLOS ONE. 9 (8): e100005. Bibcode:2014PLoSO...9j0005M. doi: 10.1371/journal.pone.0100005 . PMC   4131874 . PMID   25118592.
  14. ↑ Campos, Hebert Bruno Nascimento (August 2022). "A new azhdarchoid pterosaur from the Late Cretaceous Javelina Formation of Texas". Biologia. 77 (8): 2255. Bibcode:2022Biolg..77.2255C. doi:10.1007/s11756-021-00841-7. (Retracted, see doi:10.1007/s11756-021-00841-7)
  15. ↑ Pêgas, Rodrigo V.; Holgado, Borja; Ortiz David, Leonardo D.; Baiano, Mattia A.; Costa, Fabiana R. (2022). "On the pterosaur Aerotitan sudamericanus (Neuquén Basin, Upper Cretaceous of Argentina), with comments on azhdarchoid phylogeny and jaw anatomy". Cretaceous Research. 129: 104998. Bibcode:2022CrRes.12904998P. doi:10.1016/j.cretres.2021.104998.
  16. ↑ Bennett, S.C. (2001). "The osteology and functional morphology of the Late Cretaceous pterosaur Pteranodon Part I: General description of Osteology". Palaeontographica, Abteilung A. 260 (1–6): 1–112. Bibcode:2001PalAA.260....1B. doi:10.1127/pala/260/2001/1. S2CID   90380603. Archived from the original on June 27, 2020. Retrieved October 28, 2017.
  17. ↑ Sanchez, M.L.; Calvo, J.O.; Heredia, S. (2005). "Paleoambientes de sedimentación del tramo superior de la Formación Portezuelo, Grupo Neuquén (Cretácico Superior), Los Barreales, provincia del Neuquén" [Paleoenvironment from sediments of the upper section of the Portezuelo Formation, Neuquén Group (Upper Cretaceous), Los Barreales, province of Neuquén]. Revista de la Asociación Geológica Argentina (Magazine of the Geological Association of Argentina). 60 (1). ISSN   1851-8249.
  18. ↑ Kellner, A.W.A.; Calvo, J.O.; Sayão, J.M.; Porfiri, J.D. (2006). "Pterosaur bones from the Portezuelo Formation (Cretaceous), Neuquén Group, Patagonia, Argentina". Arquivos do Museu Nacional, Rio de Janeiro (Archives of the National Museum, Rio de Janeiro). 64 (4): 368–375. ISSN   0365-4508.
  19. ↑ Cordorniú, L.; Gasparini, Z. (2007). "Pterosauria". In Gasparini, Z.; Salgado, L.; Coria, R. (eds.). Patagonian Mesozoic Reptiles. Bloomington: Indiana University Press. pp. 143–166. ISBN   978-0-253-34857-9.
  20. ↑ Calvo, J. O.; Porfiri, J.D.; Veralli, C.; Novas, F.E.; Poblete, F. (2004). "Phylogenetic status of Megaraptor namunhuaiquii Novas based on a new specimen from Neuquén, Patagonia, Argentina". Ameghiniana. 41: 565–575.
  21. ↑ Calvo, J.O.; Porfiri, J.D.; Kellner, A.W.A. (2004). "On a new maniraptoran dinosaur (Theropoda) from the Upper Cretaceous of Neuquén, Patagonia, Argentina". Arquivos do Museu Nacional, Rio de Janeiro (Archives of the National Museum, Rio de Janeiro). 62 (4): 549–566. ISSN   0365-4508.
  22. ↑ Calvo, J.O.; Porfiri, J.D.; González Riga, B.J.; Kellner, A.W.A. (2007). "Anatomy of Futalognkosaurus dukei Calvo, Porfiri, González Riga, & Kellner, 2007 (Dinosauria, Titanosauridae) from the Neuquen Group, Late Cretaceous, Patagonia, Argentina". Arquivos do Museu Nacional, Rio de Janeiro (Archives of the National Museum, Rio de Janeiro). 65 (4): 511–526.
  23. 1 2 Calvo, J.O.; Porfiri, J.D.; González-Riga, B.J.; Kellner, A.W. (2007). "A new Cretaceous terrestrial ecosystem from Gondwana with the description of a new sauropod dinosaur". Anais da Academia Brasileira de Ciências. 79 (3): 529–541. doi: 10.1590/S0001-37652007000300013 . PMID   17768539.
  24. ↑ Porfiri, J.D. (2010). "New material of Peirosaurids in Neuquén, Patagonia: its age". Brazilian Geographical Journal: Geosciences and Humanities Research Medium. 1 (1): 50–64.
  25. ↑ Passalia M.G.; Prámparo, M.B.; Calvo, J.; Heredia, S. (2008). "Primer registro de hojas de angiospermas en el Grupo Neuquén (Turoniano tardío-Coniaciano temprano), Lago Barreales, Argentina" [First record of angiosperm leaves in the Neuquén Group (Late Turonian-Early Coniacian), Lake Barreales, Argentina]. Ameghiniana. 45 (1): 233–240.
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