Jainosaurus

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Jainosaurus
Temporal range: Late Cretaceous, 68  Ma
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Jainosaurus septentrionalis life restoration.png
Life restoration of Jainosaurus septentrionalis
Scientific classification OOjs UI icon edit-ltr.svg
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

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.

History

Life restoration of Jainosaurus (left background) with contemporary dinosaurs Morning hunting in India.jpg
Life restoration of Jainosaurus (left background) with contemporary dinosaurs

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]

Skeletal comprising of all the material referred to it by Wilson et al., 2009. Blue is preserved, orange is extrapolated and red is material broken after excavation. Jainosaurus skeletal.png
Skeletal comprising of all the material referred to it by Wilson et al., 2009. Blue is preserved, orange is extrapolated and red is material broken after excavation.

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]

Related Research Articles

<span class="mw-page-title-main">Titanosauria</span> Extinct clade of dinosaurs

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.

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

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<i>Antarctosaurus</i> Sauropod dinosaur genus from Late Cretaceous

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.

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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.

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

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.

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

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

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

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

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<span class="mw-page-title-main">Lameta Formation</span> Geologic formation in India

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

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<span class="mw-page-title-main">Sohan Lal Jain</span> Indian paleontologist

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.

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References

  1. Paul, Gregory S. (2016). The Princeton Field Guide to Dinosaurs. Princeton University Press. pp. 232–234. ISBN   978-1-78684-190-2. OCLC   985402380.
  2. R. Lydekker. 1877. Notices of new and other Vertebrata from Indian Tertiary and Secondary rocks. Records of the Geological Survey of India 10(1):30–43
  3. F. v. Huene and C. A. Matley, 1933, "The Cretaceous Saurischia and Ornithischia of the Central Provinces of India", Palaeontologica Indica (New Series), Memoirs of the Geological Survey of India, 21(1): 1–74
  4. "Dinosauria Translation and Pronunciation Guide J". dinosauria.com. Archived from the original on 25 December 2010. Retrieved 11 January 2022.
  5. Sahni, Ashok (2001). Dinosaurs of India. National Book Trust, New Delhi. ISBN   81-237-3109-4.
  6. Berman, D. S. and S. L. Jain, 1982, "The braincase of a small sauropod dinosaur (Reptilia: Saurischia) from the Upper Cretaceous Lameta Group, Central India, with review of Lameta Group localities", Annals of the Carnegie Museum51: 405–422
  7. Jain, Sohan L.; Bandyopadhyay, Saswati (1997). "New Titanosaurid (Dinosauria: Sauropoda) from the Late Cretaceous of Central India". Journal of Vertebrate Paleontology. Norman, Okla.: University of Oklahoma. 17 (1): 114. doi:10.1080/02724634.1997.10010958.
  8. Wilson, Jeffrey A.; Upchurch, P. (2003). "A revision of Titanosaurus Lydekker (Dinosauria – Sauropoda), the first dinosaur genus with a 'Gondwanan' distribution" (PDF). Journal of Systematic Palaeontology. Cambridge, U.K.: Cambridge University Press. 1 (3): 125–160. doi:10.1017/s1477201903001044. Retrieved December 31, 2012.
  9. Hunt, A.P., Lockley M., Lucas S. & Meyer C., 1995, "The global sauropod fossil record", In: M.G. Lockley, V.F. dos Santos, C.A. Meyer, and A.P. Hunt, (eds.) Aspects of sauropod paleobiology, GAIA10: 261–279
  10. Wilson, Jeffrey; D'Emic, Michael; Rogers, Christina A. Curry; Mohabey, Dhananjay M.; Sen, Subashis, 2009, "Reassessment of Sauropod Dinosaur Jainosaurus (="Antarctosaurus") septentrionalis from the Upper Cretaceous of India", Contributions from the Museum of Paleontology, University of Michigan, 32(2): 17–40