Jainosaurus Temporal range: Late Cretaceous, | |
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Life restoration of Jainosaurus septentrionalis | |
Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Clade: | Dinosauria |
Clade: | Saurischia |
Clade: | † Sauropodomorpha |
Clade: | † Sauropoda |
Clade: | † Macronaria |
Clade: | † Titanosauria |
Clade: | † Colossosauria |
Genus: | † Jainosaurus Hunt et al., 1995 |
Type species | |
†Jainosaurus septentrionalis Hunt et al., 1995 | |
Synonyms | |
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Jainosaurus is a genus of titanosaurian sauropod dinosaur of India and wider Asia, which lived in the Maastrichtian (approximately 68 million years ago). It is thought to have been about the same size as its contemporary relative Isisaurus , measuring 18 metres (59 ft) long and weighing 15 metric tons (17 short tons). [1] The humerus of the type specimen is 134 centimetres long.
The type species of Jainosaurus, J. septentrionalis has a long and complex taxonomic history closely connected to the history of the problematic genera Titanosaurus and Antarctosaurus . The first known remains attributable to Jainosaurus, the humerus GSI K22/754, was discovered in 1871 or 1872 by Henry Benedict Medlicott, [2] and the holotype remains were found by Charles Alfred Matley between 1917 and 1920 near Jabalpur in the Lameta Formation. These were named Antarctosaurus septentrionalis by Friedrich von Huene and Matley in 1933. [3]
The specific name of J. septentrionalis means "northern" in Latin, a reference to the fact that the species was discovered on the Northern hemisphere whereas Antarctosaurus means "saurian from the Southern hemisphere" because its type species Antarctosaurus wichmannianus was found in Argentina. The generic name honours the Indian paleontologist Sohan Lal Jain, [4] who worked on the cranial nerve impressions in the skull; [5] and in 1982 published a study about the results. [6] Ironically, Jain himself considered the remains synonymous with Titanosaurus in the 1997 description of Isisaurus. [7] However, Wilson and Upchurch (2003) rejected the synonymy of Jainosaurus and Titanosaurus due to the dubious status of the latter. [8]
In 1995 Hunt et al., believing Antarctosaurus to belong to Dicraeosauridae, made the clearly titanosaurian Antarctosaurus septentrionalis the type species of a new genus, Jainosaurus, and determined that the braincase, GSI IM K27/497, should be the lectotype. [9] Jainosaurus was further distinguished from Antarctosaurus by details of the braincase.
In 2009, Jeffrey Wilson and others made a detailed reassessment of Jainosaurus septentrionalis and confirmed its validity. The postcrania, which had been assumed lost, were shown to be largely present in the collection of the Geological Survey of India at Calcutta. They include: dorsal rib fragments (GSI K20/326, K27/425); a caudal vertebra (GSI K20/317), four chevrons (GSI K27/492–494, 496), the left and right scapula (only a cast still extant); a sternal plate (GSI K20/647); a humerus (lacking an inventory number), a radius (GSI K27/490) and an ulna (GSI K27/491). In 1996 Sankar Chatterjee referred a second braincase to the species: ISI R162. Some material from Pakistan also possibly belongs to Jainosaurus.
Wilson e.a. concluded that Jainosaurus is a valid taxon, clearly distinguishable from Isisaurus . It would have been a fairly derived member of the Titanosauria, more closely related to South American forms like Pitekunsaurus , Muyelensaurus and Antarctosaurus than to Isisaurus or Rapetosaurus . [10]
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.
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.
Antarctosaurus is a genus of titanosaurian sauropod dinosaur from the Late Cretaceous Period of what is now South America. The type species, Antarctosaurus wichmannianus, and a second species, Antarctosaurus giganteus, were described by prolific German paleontologist Friedrich von Huene in 1929. Three additional species of Antarctosaurus have been named since then but later studies have considered them dubious or unlikely to pertain to the genus.
Indosuchus is a genus of abelisaurid dinosaur from the Late Cretaceous Period, a theropod related to Abelisaurus. Like most theropods, Indosuchus was a bipedal carnivore. It was about 7 metres long, weighed about 1.2 tonnes, and had a crested skull, flattened on the top.
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.
Adamantisaurus is a poorly-known genus of titanosaurian sauropod dinosaur from the Late Cretaceous Period of what is now South America. It is only known from six tail vertebrae but, as a sauropod, it can be assumed that this dinosaur was a very large animal with a long neck and tail.
Jeffrey A. Wilson, also known as JAW, is a paleontologist and professor of geological sciences and assistant curator at the Museum of Paleontology at the University of Michigan.
Indosaurus is a genus of carnivorous theropod dinosaur that lived in what is now India, about 69 to 66 million years ago during the Maastrichtian division of the Late Cretaceous.
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.
Coeluroides is an extinct genus of theropod dinosaur that lived during the Late Cretaceous Period in what is now India. It is based solely on the holotype caudal vertebrae GSI K27/562, K27/574 and K27/595, discovered in a layer of the Lameta Formation. The type species, C. largus, was described by Friedrich von Huene and Charles Alfred Matley in 1933.
Compsosuchus is a dubious genus of abelisauroid dinosaur from the Late Cretaceous Lameta Formation of India.
Isisaurus is a genus of titanosaurian dinosaur from the Late Cretaceous Lameta Formation of India and Pab Formation of Pakistan. The genus contains a single species, Isisaurus colberti.
Dryptosauroides is the name given to a dubious genus of dinosaur from the Late Cretaceous. It was a large theropod, possibly belonging to the Abelisauroidea. It has been estimated as 10 meters long and 1.5 tonnes in weight.
Laevisuchus is a genus of theropod dinosaur from the Late Cretaceous. Its remains were discovered by Charles Alfred Matley near Jabalpur in Maastrichtian "Carnosaur Bed" deposits in the Lameta Formation in Madhya Pradesh, central India, and were named and described by paleontologists Friedrich von Huene and Matley in 1933.
Neuquensaurus 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.
The Lameta Formation, also known as the Infratrappean Beds, is a sedimentary geological formation found in Madhya Pradesh, Gujarat, Maharashtra, Telangana, and Andhra Pradesh, India, associated with the Deccan Traps. It is of the Maastrichtian age, and is notable for its dinosaur fossils
Lithostrotia is a clade of derived titanosaur sauropods that lived during the Early Cretaceous and Late Cretaceous. The group was defined by Upchurch et al. in 2004 as the most recent common ancestor of Malawisaurus and Saltasaurus and all the descendants of that ancestor. Lithostrotia is derived from the Ancient Greek lithostros, meaning "inlaid with stones", referring to the fact that many known lithostrotians are preserved with osteoderms. However, osteoderms are not a distinguishing feature of the group, as the two noted by Unchurch et al. include caudal vertebrae with strongly concave front faces (procoely), although the farthest vertebrae are not procoelous.
Sohan Lal Jain is an Indian paleontologist, who worked for 33 years at the Indian Statistical Institute, Kolkata. The large herbivorous sauropod dinosaur genus Jainosaurus, was named in his honour after it was identified as a distinct genus although initially thought to be a species of Antarctosaurus. His other major contributions to paleontology were in the study of sauropod braincases and some fossil turtles.
Pitekunsaurus is a genus of titanosaurian sauropod dinosaur from the Late Cretaceous Anacleto Formation of Neuquén, Argentina. It was described by L. Filippi and A. Garrido in 2008. The type species is P. macayai. The generic name is derived from Mapudungun pitekun, meaning "to discover", the epitheton honours the discoverer, oil company explorer Luis Macaya, who found the fossil in April 2004.
Saltasaurinae is a subfamily of titanosaurian sauropods known from the late Cretaceous period of South America, India and Madagascar.