Patagotitan

Patagotitan is a genus of titanosaurian sauropod from the Cerro Barcino Formation in Chubut Province, Patagonia, Argentina. The genus contains a single species known from multiple individuals: Patagotitan mayorum, first announced in 2014 and then validly named in 2017 by José Carballido, Diego Pol and colleagues. Contemporary studies estimated the length of the type specimen, a young adult, at 37 m (121 ft)[1] with an approximate weight of 69 tonnes (76 tons).[2]

Patagotitan
Temporal range: Albian
101.62 Ma
FMNH Patagotitan
Reconstructed skeleton on display at the Field Museum of Natural History, Chicago, IL
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Order: Saurischia
Suborder: Sauropodomorpha
Clade: Sauropoda
Clade: Titanosauria
Clade: Lithostrotia
Clade: Lognkosauria
Genus: Patagotitan
Carballido et al., 2017
Type species
Patagotitan mayorum
Carballido et al., 2017

Discovery

Fémur del Titanosauria del Chubut en el MEF 02
Femur

Remains of Patagotitan, a part of a lower thighbone, were initially discovered in 2008 by a farm laborer, Aurelio Hernández, in the desert near La Flecha, about 250 km (160 mi) west of Trelew. Excavation was done by palaeontologists from the Museum of Paleontology Egidio Feruglio. The lead scientists on the excavation were Jose Luis Carballido and Diego Pol, with partial funding from The Jurassic Foundation. Between January 2013 and February 2015, seven paleontological field expeditions were carried out to the La Flecha fossil site, recovering more than 200 fossils, both of sauropods and theropods (represented by 57 teeth). At least six partial skeletons, consisting of approximately 130 bones, were uncovered, making Patagotitan one of the most complete titanosaurs currently known.[2]

The type species Patagotitan mayorum was named and described by José Luis Carballido, Diego Pol, Alejandro Otero, Ignacio Alejandro Cerda, Leonardo Salgado, Alberto Carlos Garrido, Jahandar Ramezani, Néstor Ruben Cúneo and Javier Marcelo Krause in 2017. The generic name combines a reference to Patagonia with a Greek Titan for the "strength and large size" of this titanosaur. The specific name honours the Mayo family, owners of La Flecha ranch.[2]

Fósiles del titanosauria del Chubut en el Museo Egidio Feruglio de Trelew 20
Vertebra

The holotype, MPEF-PV 3400, was found in a layer of the Cerro Barcino Formation, dating from the latest Albian. The particular stratum has an age of 101.62 plus or minus 0.18 million years ago. The holotype consists of a partial skeleton lacking the skull. It contains three neck vertebrae, six back vertebrae, six front tail vertebrae, three chevrons, ribs, both breast bones, the right scapulocoracoid of the shoulder girdle, both pubic bones and both thighbones. The skeleton was chosen to be the holotype because it was the best preserved and also the one showing the most distinguishing traits. Other specimens were designated as the paratypes. Specimen MPEF-PV 3399 is a second skeleton including six neck vertebrae, four back vertebrae, one front tail vertebra, sixteen rear tail vertebrae, ribs, chevrons, the left lower arm, both ischia, the left pubic bone and the left thighbone. Specimen MPEF-PV 3372 is a tooth. Specimen MPEF-PV 3393 is a rear tail vertebra. Specimen MPEF-PV 3395 is a left humerus as is specimen MPEF-PV 3396, while specimen MPEF-PV 3397 is a right humerus. Specimen MPEF-PV 3375 is a left thighbone while MPEF-PV 3394 is a right one. Specimens MPEF-PV 3391 and MPEF-PV3392 represent two calfbones.[2]

The animals found, though excavated in one quarry, did not all die at the same time. Within the 343 centimetre thick sediment containing the fossils, three distinct but closely spaced horizons correspond to three burial events in which young adults perished due to floods. The water did not transport the carcasses any further but covered them with sandstone and mudstone.[2] The animals were about the same size, differing no more than 5% in length. As far as can be ascertained, all bones discovered belong to the same species and are thus part of a monospecific assemblage.[2]

Description and size

Patagotitan-Scale-Diagram-Steveoc86
P. mayorum compared to a human.

Like other titanosaur sauropods, Patagotitan was a quadrupedal herbivore with a long neck and tail and is notable for its large size. In 2014 news reports stated size estimates of 40 m (131 ft) long with a weight of 77 tonnes (85 tons);[3][1] science writer Brian Switek had cautioned in 2014 that it was still too early to make size estimates with the desirable scientific certainty.[4] In 2017 the species description of Patagotitan mayorum was published which estimated a length of 37 m (121 ft) long,[1] with an approximate weight of 69 tonnes (76 tons).[2]

The researchers who described Patagotitan stated in the media:[5]

Given the size of these bones, which surpass any of the previously known giant animals, the new dinosaur is the largest animal known that walked on Earth.

Fósiles del titanosauria del Chubut en el Museo Egidio Feruglio de Trelew 03
Front limb and shoulder blade at Museo Egidio Feruglio de Trelew, Chubut

Following the publication of Patagotitan, Brian Switek and paleontologist Matt Wedel further cautioned against the media hype. In blog posts, Wedel noted that based on available measurements Patagotitan was comparable in size to other known giant titanosaurs, however, almost every bone measurement that could be compared are larger in Argentinosaurus. Wedel also criticised the researchers mass estimation technique. [6][7][8] In other studies Argentinosaurus has been estimated at 73–96.4 tonnes (80.5–106.3 tons).[9][10][11]

Distinguishing traits

The authors indicated nine distinguishing traits of Patagotitan. The first three back vertebra have a lamina prezygodiapophysealis, a ridge running between the front articular process and the side process, that is vertical because the front articular process is situated considerably higher than the side process. With the first two back vertebrae, the ridge running to below from the side front of the neural spine has a bulge at the underside. Secondary articulating processes of the hyposphene-hypantrum complex type are limited to the articulation between the third and fourth back vertebra. The middle and rear back vertebrae have vertical neural spines. In the first tail vertebra, the centrum or main vertebral body has a flat articulation facet in front and a convex facet at the rear. The front tail vertebrae have neural spines of which the transverse width is four to six times larger than their length measured from the front to the rear. The front tail vertebrae have neural spines that show some bifurcation. The upper arm bone has a distinct bulge on the rear outer side. The lower thighbone has a straight edge on the outer side.[2]

Classification

Fósiles del titanosauria del Chubut en el Museo Egidio Feruglio de Trelew 21
Chevrons and other bones
Patagotitan at dawn
Life restoration of two Patagotitan at dawn

In 2017, Patagotitan was placed, within the Titanosauria, in the Eutitanosauria and more precisely the Lognkosauria, as a sister species of Argentinosaurus. Several subclades of the Titanosauria would have independently acquired a large body mass. One such event would have taken place at the base of the Notocolossus + Lognkosauria clade leading to a tripling of weight from maximal twenty to maximal sixty tonnes.[2]

Eutitanosauria

Dreadnoughtus

Lithostrotia

Malawisaurus

Baurutitan

Nemegtosaurus

Trigonosaurus

Alamosaurus

Opisthocoelicaudia

Saltasaurus

Neuquensaurus

Rapetosaurus

Isisaurus

Tapuiasaurus

Rinconsauria

Rinconsaurus

Muyelensaurus

Aeolosaurus

Overosaurus

Bonitasaura

Notocolossus

Lognkosauria

Mendozasaurus

Futalognkosaurus

Quetecsaurus

Puertasaurus

Drusilasaura

Argentinosaurus

Patagotitan

Paleoecology

AMNHTitanosaur-03
Reconstructed skeleton on display at the American Museum of Natural History, New York

Patagotitan lived during the Late Cretaceous period, between 102 and 95 million years ago, in what was then a forested region.[3][12][13] The bearing sediments indicate that sedimentation took place with a low energy setting, related to floodplains of a meandering system (Carmona et al., 2016).[2]

See also

Further reading

References

  1. ^ a b c Giant dinosaur slims down a bit. BBC News Science & Environment
  2. ^ a b c d e f g h i j Carballido, J.L.; Pol, D.; Otero, A.; Cerda, I.A.; Salgado, L.; Garrido, A.C.; Ramezani, J.; Cúneo, N.R.; Krause, J.M. (2017). "A new giant titanosaur sheds light on body mass evolution among sauropod dinosaurs". Proceedings of the Royal Society B: Biological Sciences. 284 (1860): 20171219. doi:10.1098/rspb.2017.1219. PMC 5563814. PMID 28794222.
  3. ^ a b Morgan, James (17 May 2014). "BBC News - 'Biggest dinosaur ever' discovered". BBC News. Bbc.com. Retrieved 17 May 2014.
  4. ^ Yong, Ed (18 May 2014). "Biggest Dinosaur Ever? Maybe. Maybe Not. – Phenomena". BMC Biology. 10: 60. doi:10.1186/1741-7007-10-60. PMC 3403949. PMID 22781121. Retrieved 11 June 2016.
  5. ^ Morgan, James (17 May 2014). "'Biggest dinosaur ever' discovered". BBC News. Retrieved 8 January 2019.
  6. ^ Switek, Brian. "Did Scientists Just Unveil the Biggest Dinosaur of All Time?". Smithsonian. Retrieved 8 January 2019.
  7. ^ "Don't believe the hype: Patagotitan was not bigger than Argentinosaurus". Sauropod Vertebra Picture of the Week. 9 August 2017. Retrieved 8 January 2019.
  8. ^ "Some further thoughts on Patagotitan". Sauropod Vertebra Picture of the Week. 10 August 2017. Retrieved 8 January 2019.
  9. ^ Mazzetta, G.V.; Christiansen, P.; Farina, R.A. (2004). "Giants and bizarres: body size of some southern South American Cretaceous dinosaurs" (PDF). Historical Biology. 2004 (2–4): 1–13. CiteSeerX 10.1.1.694.1650. doi:10.1080/08912960410001715132.
  10. ^ Sellers, W. I.; Margetts, L.; Coria, R. A. B.; Manning, P. L. (2013). Carrier, David (ed.). "March of the Titans: The Locomotor Capabilities of Sauropod Dinosaurs". PLoS ONE. 8 (10): e78733. Bibcode:2013PLoSO...878733S. doi:10.1371/journal.pone.0078733. PMC 3864407. PMID 24348896.
  11. ^ González Riga, Bernardo J.; Lamanna, Matthew C.; Ortiz David, Leonardo D.; Calvo, Jorge O.; Coria, Juan P. (2016). "A gigantic new dinosaur from Argentina and the evolution of the sauropod hind foot". Scientific Reports. 6: 19165. Bibcode:2016NatSR...619165G. doi:10.1038/srep19165. ISSN 2045-2322. PMC 4725985. PMID 26777391.
  12. ^ Gillian Mohney via Good Morning America (17 May 2014). "Researchers Discover Fossils of Largest Dino Believed to Ever Walk the Earth - ABC News". Abcnews.go.com. Retrieved 17 May 2014.
  13. ^ "Argentine fossil biggest dinosaur ever: scientists". NY Daily News. Retrieved 17 May 2014.

External links

Argentinosaurus

Argentinosaurus (meaning "Argentine lizard") is a genus of titanosaur sauropod dinosaur first discovered by Guillermo Heredia in Argentina. The generic name refers to the country in which it was discovered. The dinosaur lived on the then-island continent of South America somewhere between 97 and 93.5 million years ago, during the Late Cretaceous Period. It is among the largest known dinosaurs.

Brasilotitan

Brasilotitan is a genus of titanosaurian sauropod dinosaur from the Late Cretaceous (early Maastrichtian) Adamantina Formation of Brazil. The type species is Brasilotitan nemophagus.

Bruhathkayosaurus

Bruhathkayosaurus (; meaning "huge-bodied lizard") is a genus of dinosaur found in India. The fragmentary remains were originally described as a theropod but later publications listed it as a sauropod. Estimates by researchers exceed those of the titanosaur Argentinosaurus, as longer than 35 metres (115 ft) and weighing over 80-200 tons. All the estimates are based on the dimensions of the fossils described in Yadagiri and Ayyasami's 1987 paper, which announced the find. In 2017 it was reported that the original fossils had disintegrated and no longer exist.

Ferganasaurus

Ferganasaurus was a genus of dinosaur first formally described in 2003 by Alifanov and Averianov. The type species is Ferganasaurus verzilini. It was a sauropod similar to Rhoetosaurus. The fossils were discovered in 1966 in Kyrgyzstan from the Balabansai Formation and date to the Callovian stage of the Middle Jurassic.

Gravisauria

Gravisauria is a clade of sauropod dinosaurs consisting of some genera, Vulcanodontidae and Eusauropoda.

Jiutaisaurus

Jiutaisaurus is a genus of sauropod dinosaur from the Quantou Formation of China. Jiutaisaurus was a sauropod which lived during the Cretaceous. The type species, Jiutaisaurus xidiensis, was described by Wu et al. in 2006, and is based on eighteen vertebrae.

Lognkosauria

Lognkosauria is a group of giant long-necked sauropod dinosaurs within the clade Titanosauria. It includes some of the largest and heaviest dinosaurs known.

Malarguesaurus

Malarguesaurus is a genus of titanosauriform sauropod dinosaur from the Late Cretaceous of Mendoza Province, Argentina. Its fossils, consisting of tail vertebrae, chevrons, ribs, and limb bones, were found in the late Turonian-early Coniacian-age (~89 million years old) Portezuelo Formation of the Neuquén Group. The type species, described by González Riga et al. in 2008, is M. florenciae.

Mendozasaurus

Mendozasaurus is a genus of sauropod dinosaur. It was a member of Titanosauria, which were massive sauropods that were common on the southern landmasses during the Cretaceous period. The titanosaurian sauropod dinosaur Mendozasaurus neguyelap is represented by several partial skeletons from a single locality within the Coniacian (lower Upper Cretaceous) Sierra Barrosa Formation in the south of Mendoza Province, northern Neuquén Basin, Argentina.

The type species, Mendozasaurus neguyelap, was described by Argentine paleontologist Bernardo Javier González Riga in 2003. Mendozasaurus is the first dinosaur named from Mendoza Province, Argentina.

Microcoelus

Microcoelus is a dubius genus of small Titanosaurian sauropod dinosaur native to Argentina. It is known from only a single dorsal vertebra. A left humerus was formerly referred to this species, but it is now considered to belong to Neuquensaurus. This species may be a synonym of the contemporary sauropod Neuquensaurus australis.It was described by British paleontologist Richard Lydekker in 1893.

Nemegtosauridae

Nemegtosauridae is a family of titanosaurian sauropod dinosaurs based originally on two late Cretaceous Mongolian species known only from their diplodocid-like skulls: Nemegtosaurus and Quaesitosaurus.

Neosauropoda

Neosauropoda is a clade within Dinosauria, coined in 1986 by Argentine paleontologist José Bonaparte and currently described as Saltasaurus loricatus, Diplodocus longus, and all animals directly descended from their most recent common ancestor. The group is composed of two subgroups: Diplodocoidea and Macronaria. Arising in the early Jurassic and persisting until the Cretaceous-Paleogene extinction event, Neosauropoda contains the majority of sauropod genera, including genera such as Apatosaurus, Brachiosaurus, and Diplodocus. It also includes giants such as Argentinosaurus, Patagotitan and Sauroposeidon, and its members remain the largest land animals ever to have lived.When Bonaparte first coined the term Neosauropoda in 1986, he described the clade as comprising “end-Jurassic” sauropods. While Neosauropoda does appear to have originated at the end of the Jurassic period, it also includes members through the end of the Cretaceous. Neosauropoda is currently delineated by specific shared, derived characteristics rather than the time period in which its members lived. The group was further refined by Upchurch, Sereno, and Wilson, who have identified thirteen synapomorphies shared among neosauropods. As Neosauropoda is a subgroup of Sauropoda, all members also display basic sauropod traits such as large size, long necks, and columnar legs.

Notocolossus

Notocolossus is a genus of herbivorous lithostrotian titanosaur sauropod dinosaur from late Cretaceous strata of Mendoza Province, Argentina.

Pilmatueia

Pilmatueia is a diplodocoid sauropod belonging to the family Dicraeosauridae that lived in Argentina during the Early Cretaceous.

Puertasaurus

Puertasaurus is a genus of sauropod dinosaur that lived in South America during the Late Cretaceous Period. It is known from a single specimen recovered from sedimentary rocks of the Cerro Fortaleza Formation in southwestern Patagonia, Argentina, which probably is Campanian or Maastrichtian in age. The only species is Puertasaurus reuili. Described by the paleontologist Fernando Novas and colleagues in 2005, it was named in honor of Pablo Puerta and Santiago Reuil, who discovered and prepared the specimen. It consists of four well-preserved vertebrae, including one cervical, one dorsal, and two caudal vertebrae. Puertasaurus is a member of Titanosauria, the dominant group of sauropods during the Cretaceous.

Puertasaurus was a very large animal. Its size is difficult to estimate due of the scarcity of its remains, but current estimates place it around 30 meters (98 feet) long and 50 metric tons (55 short tons) in mass. The largest of the four preserved bones is the dorsal vertebra, which at 1.68 meters (5 ft 6 in) wide is the broadest known vertebra of any sauropod. The Cerro Fortaleza Formation is of uncertain age, due to the inconsistency of stratigraphic nomenclature in Patagonia. When Puertasaurus was alive, the Cerro Fortaleza Formation would have been a humid, forested landscape. Puertasaurus would have shared its habitat with other dinosaurs, including another large sauropod, Dreadnoughtus, in addition to other reptiles and fish.

Tambatitanis

Tambatitanis is an extinct genus of titanosauriform dinosaur from the Early Cretaceous (probably early Albian) of Japan. It is known from a single type species, Tambatitanis amicitiae. It was probably around 14 meters long and its mass was estimated at some 4 tonnes. It was a basal titanosauriform and possibly belonged to the Euhelopodidae.

Tengrisaurus

Tengrisaurus (meaning "Tengri lizard") is a genus of lithostrotian sauropod, from the Early Cretaceous (Barremian-Aptian), of the Murtoi Formation, Russia. It was described in 2017 by Averianov & Skutschas. The type species is T. starkovi.

Titanosauria

Titanosaurs (members of the group Titanosauria) were a diverse group of sauropod dinosaurs which included Saltasaurus and Isisaurus of Africa, Asia, South America, Europe and Australia. 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. The group includes the largest land animals known to have existed, such as Patagotitan—estimated at 37 m (121 ft) long with a weight of 69 tonnes (76 tons)—and the comparably sized Argentinosaurus and Puertasaurus from the same region. The group's name alludes to the mythological Titans of Ancient Greece, via the type genus (now considered a nomen dubium) Titanosaurus. Together with the brachiosaurids and relatives, titanosaurs make up the larger clade Titanosauriformes.

Vulcanodontidae

The Early Jurassic sauropod dinosaurs Zizhongosaurus, Barapasaurus, Tazoudasaurus, and Vulcanodon may form a natural group of basal sauropods called the Vulcanodontidae. Basal vulcanodonts include some of the earliest known examples of sauropods. The family-level name Vulcanodontidae was erected by M.R. Cooper in 1984. In 1995 Hunt et al. published the opinion that the family is synonymous with the Barapasauridae. One of the key morphological features specific to the family is an unusually narrow sacrum.

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