González Riga et al., 2016
González Riga et al., 2016
In 2016, the type species Notocolossus gonzalezparejasi was named and described by Bernardo Javier González Riga, Matthew Carl Lamanna, Leonardo Daniel Ortiz David, Jorge Orlando Calvo and Juan P. Coria. The generic name combines the Greek words νότος, notos, "south wind", and κολοσσός, kolossos, "giant statue", in reference to the provenance from the Southern Hemisphere and the gigantic size of the animal. The specific name honours Jorge González Parejas, for having studied the dinosaur fossils of Mendoza province for two decades.
The holotype, UNCUYO-LD 301, was found in a layer of the Plottier Formation dating from the Coniacian-Santonian, about eighty-six million years old. It consists of a partial skeleton lacking the skull. It contains an anterior back vertebra, an anterior tail vertebra, a right humerus and the upper part of a left pubic bone. Although the bones have not been discovered in articulation, they were considered to represent a single individual because they were found in close association on a surface of eight by eight metres. A second partial skeleton lacking the skull was referred to Notocolossus: specimen UNCUYO-LD 302 representing a smaller individual. It contains a series of five anterior tail vertebrae and a complete right foot connected to an astragalus. It was recovered on a distance of 403 metres to the holotype from a surface of five by five metres.
The evidence suggests that Notocolossus was among the largest titanosaurs, and therefore one of the heaviest land animals, yet discovered. Although the incompleteness of the skeleton of the new sauropod has prevented scientists from making precise estimates of its size, its humerus, or upper arm bone, is 1.76 m (5 ft 9 in) in length, which is longer than that of any other titanosaur for which this bone is known, including other giants such as Dreadnoughtus, Futalognkosaurus, and Paralititan. If, as is likely, the body proportions of Notocolossus were comparable to those of better preserved titanosaurs, the new dinosaur may have weighed in the range of 44.9–75.9 tonnes (44.2–74.7 long tons; 49.5–83.7 short tons), most likely 60.4 tonnes (59.4 long tons; 66.6 short tons).
In 2016, several distinguishing traits of Notocolossus were determined. Nine of these were autapomorphies, unique derived qualities. At the anterior back vertebra, the depression between the front edge of the side process and the lower edge of the side process is divided by two accessory ridges, one of which runs vertically while the other crosses the first horizontally. On the front side of the neural spines of the front tail vertebrae, run vertical ridges fusing at their lower ends, above the level of the front joint processes, creating a V-shaped structure. The upper inner corner of the humerus is strongly expanded, extending far beyond the inner side of the shaft. The humerus has in general a strongly expanded upper edge, 2.9 wider than the shaft diameter. On the humerus shaft, below the scar for the musculus coracobrachialis, runs a diagonal ridge, from the upper and outer side to the inner and lower side. The first metatarsal has an upper width exceeding its length. The third metatarsal is relatively short with 1.2 times the length of the first metatarsal. The upper toe phalanges are 50% wider at their tops than their respective metatarsals are long. The toe claws are reduced, rough and truncated.
The foot or pes of Notocolossus, a skeleton part that is not often preserved in sauropods, shows a unique build. It contains a compact, homogeneous metatarsus, thought to be adapted for bearing extraordinary weight. It also presents truncated unguals, characteristics otherwise unknown in the Sauropoda. This parallels the vertical position of the metacarpals and the finger reduction in the hand of other titanosaurs.
Notocolossus belongs to the clade Titanosauria, a very diverse group of sauropods. In 2016, a cladistic analysis recovered Notocolossus as a basal member of Lithostrotia and a sister species of Dreadnoughtus. A 2017 study by Carballido and colleagues recovered it as the sister taxon of Lognkosauria and found it to be outside of Lithostrotia. In 2018, González Riga and colleagues found it to belong to Lognkosauria, in a polytomy with Patagotitan and Puertasaurus. This analysis also found Longkosauria to belong to Lithostrotia.
Notocolossus was discvoered in the Plottier Formation of the Neuquén Group. This formation is about 25 metres (82 ft) thick and composed of light red claystones and thin bands of pink sandstone. The Plottier Formation can be differentiated from the overlying Portezuelo Formation by the former's higher content of argillite. Tetrapods of the Plottier formation are poorly known. They are represented by mammals, a large coelurosaur, and several titanosaurs. These titanosaurs, in addition to Notocolossus, include Petrobrasaurus, "Antarctosaurus" giganteus, and two additional specimens, one of which appears to be an aeolosaurine. Additionally Muyelensaurus is sometimes stated to come from this formation, although it may actually be from the aforementioned Portezuelo Formation instead.
Apatosaurinae is the name of a subfamily of diplodocid sauropods that existed between 157 and 150 million years ago in North America. The group includes two genera for certain, Apatosaurus and Brontosaurus, with at least five species. Atlantosaurus and Amphicoelias might also belong to this group.Below is a cladogram of apatosaurinae interrelationships based on Tschopp et al., 2015.Argyrosauridae
Argyrosauridae is a family of large titanosaurian dinosaurs known from the late Cretaceous period of Argentina and Egypt. The group has been recovered as monophyletic, including the type genus Argyrosaurus as well as Paralititan.Bernardo Javier González Riga
Bernardo Javier González Riga is an Argentinean paleontologist. He has discovered in the Late Cretaceous strata of the Mendoza Province (Argentina) the huge sauropod dinosaur named Notocolossus, one of the largest land animal that ever found. He also described and co-described many new dinosaur species.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.Cetiosauridae
Cetiosauridae is a family of sauropod dinosaurs. While traditionally a wastebasket taxon containing various unrelated species, some recent studies have found that it may represent a natural clade. Additionally, at least one study has suggested that the mamenchisaurids may represent a sub-group of the cetiosaurids, which would be termed Mamenchisaurinae.Diplodocinae
Diplodocinae is an extinct subfamily of diplodocid sauropods that existed from the Late Jurassic to Early Cretaceous of North America, Europe and South America, about 161.2 to 136.4 million years ago. Genera within the subfamily include Tornieria, Supersaurus, Leinkupal, Galeamopus, Diplodocus, Kaatedocus and Barosaurus.Cladogram of the Diplodocidae after Tschopp, Mateus, and Benson (2015).Eomamenchisaurus
Eomamenchisaurus (meaning "dawn Mamenchisaurus") is a genus of mamenchisaurid sauropod dinosaur from the Middle Jurassic of Yuanmou, Yunnan, China. The type species is E. yuanmouensis, described by Lü Junchang et al. in 2008.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.Flagellicaudata
Flagellicaudata is a clade of Dinosauria. It belongs to Sauropoda and includes two families, the Dicraeosauridae and the Diplodocidae.Gravisauria
Gravisauria is a clade of sauropod dinosaurs consisting of some genera, Vulcanodontidae and Eusauropoda.Huangshanlong
Huangshanlong is a genus of mamenchisaurid dinosaurs native to the Anhui province of China. It contains a single species, Huangshanlong anhuiensis. H. anhuiensis represents, along with Anhuilong and Wannanosaurus, one of three dinosaurs fround in Anhui province.Kaijutitan
Kaijutitan (meaning "Kaiju titan" after the type of Japanese movie monsters) is a genus of basal titanosaur dinosaur from the Sierra Barrosa Formation from Neuquén Province in Argentina. The type and only species is Kaijutitan maui.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.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.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) with an approximate weight of 69 tonnes (76 tons).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.Tastavinsaurus
Tastavinsaurus is a genus of sauropod dinosaur belonging to the Titanosauriformes. It is based on a partial skeleton from the Early Cretaceous of Spain. The type species is Tastavinsaurus sanzi, named in honor of the Rio Tastavins in Spain and Spanish paleontologist José Luis Sanz.