Jainosaurus
Encyclopedia
Jainosaurus is a large titanosaurian dinosaur
of India
and wider Asia
, which lived in the Maastrichtian
(approximately 68 mya).
The first remains were between 1917 and 1920 found by Charles Alfred Matley
near Jabalpur in the Lameta Formation
. These were named Antarctosaurus
septentrionalis by Friedrich von Huene
and Matley in 1933. The specific name 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
.
In 1995 Adrian Paul Hunt e.a. named a separate genus: Jainosaurus. The generic name honours the Indian paleontologist Sohan Lal Jain
, who worked on the cranial nerve impressions in the skull; and in 1982 published a study about the results. Ironically Jain himself considers this species to be likely identical to Titanosaurus
indicus, found in the same formation and named in 1877, which would make Jainosaurus septentrionalis a younger synonym. He believes that the remains represent merely a young or female Titanosaurus.
In 2009 a detailed redescription by Jeffrey Wilson e.a. chose GSI IM K27/497, a braincase (basicranium) as the lectotype
. 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
A herbivorous quadruped
, an adult Jainosaurus would have measured around eighteen metres long and held its head six metres high. No accurate estimate of the weight has yet been made. The humerus of the type specimen is 134 centimetres long.
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
.
Dinosaur
Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...
of India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
and wider Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
, which lived in the Maastrichtian
Maastrichtian
The Maastrichtian is, in the ICS' geologic timescale, the latest age or upper stage of the Late Cretaceous epoch or Upper Cretaceous series, the Cretaceous period or system, and of the Mesozoic era or erathem. It spanned from 70.6 ± 0.6 Ma to 65.5 ± 0.3 Ma...
(approximately 68 mya).
The first remains were between 1917 and 1920 found by Charles Alfred Matley
Charles Alfred Matley
Charles Alfred Matley was a British paleontologist and geologist in India, the British West Indies and Wales.He married Sarah A. Loach in Birmingham in 1891....
near Jabalpur in the Lameta Formation
Lameta Formation
The Lameta Formation is a sedimentary rock formation found in Madhya Pradesh, Gujarat, and Maharashtra, India. It is of Maastrichtian age , and is notable for its dinosaur fossils...
. These were named Antarctosaurus
Antarctosaurus
Antarctosaurus is a genus of titanosaurian sauropod dinosaur from the Late Cretaceous Period of what is now South America. The type species, A. wichmannianus, was described by prolific German paleontologist Friedrich von Huene in 1929, who also described a second species in 1929. Three additional...
septentrionalis by Friedrich von Huene
Friedrich von Huene
Friedrich von Huene was a German paleontologist who named more dinosaurs in the early 20th century than anyone else in Europe.-Biography:...
and Matley in 1933. The specific name means "northern" in Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
, a reference to the fact that the species was discovered on the Northern hemisphere
Northern Hemisphere
The Northern Hemisphere is the half of a planet that is north of its equator—the word hemisphere literally means “half sphere”. It is also that half of the celestial sphere north of the celestial equator...
whereas Antarctosaurus means "saurian from the Southern hemisphere
Southern Hemisphere
The Southern Hemisphere is the part of Earth that lies south of the equator. The word hemisphere literally means 'half ball' or "half sphere"...
" because its type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
Antarctosaurus wichmannianus was found in Argentina
Argentina
Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...
.
In 1995 Adrian Paul Hunt e.a. named a separate genus: Jainosaurus. The generic name honours the Indian paleontologist Sohan Lal Jain
Sohan Lal Jain
Sohan Lal Jain is an Indian paleontologist, who worked for many 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. It was earlier thought to be a species of...
, who worked on the cranial nerve impressions in the skull; and in 1982 published a study about the results. Ironically Jain himself considers this species to be likely identical to Titanosaurus
Titanosaurus
Titanosaurus is a genus of sauropod dinosaur, first described by Lydekker in 1877. It is known from the Maastrichtian Lameta Formation of India...
indicus, found in the same formation and named in 1877, which would make Jainosaurus septentrionalis a younger synonym. He believes that the remains represent merely a young or female Titanosaurus.
In 2009 a detailed redescription by Jeffrey Wilson e.a. chose GSI IM K27/497, a braincase (basicranium) as the lectotype
Lectotype
In botanical nomenclature and zoological nomenclature, a lectotype is a kind of name-bearing type. When a species was originally described on the basis of a name-bearing type consisting of multiple specimens, one of those may be designated as the lectotype...
. The postcrania
Postcrania
Postcrania[p] in zoology and vertebrate paleontology refers to all or part of the skeleton apart from the skull. Frequently, fossil remains, e.g...
, which had been assumed lost, were shown to be largely present in the collection of the Geological Survey of India
Geological Survey of India
Geological Survey of India , established in 1851 is a government organization in India which is an attached office to the Ministry of Mines of Union Government of India for conducting geological surveys and studies. It is one of the oldest of such organizations in the world and the second oldest...
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
Sankar Chatterjee
Sankar Chatterjee is a paleontologist, and is the Paul W. Horn Professor of Geosciences at Texas Tech University and Curator of Paleontology at the Museum of Texas Tech University. He earned his Ph. D. from the University of Calcutta in 1970 and was a Post-doctoral Fellow at the Smithsonian...
referred a second braincase to the species: ISI R162. Some material from Pakistan
Pakistan
Pakistan , officially the Islamic Republic of Pakistan is a sovereign state in South Asia. It has a coastline along the Arabian Sea and the Gulf of Oman in the south and is bordered by Afghanistan and Iran in the west, India in the east and China in the far northeast. In the north, Tajikistan...
also possibly belongs to Jainosaurus
A herbivorous quadruped
Quadruped
Quadrupedalism is a form of land animal locomotion using four limbs or legs. An animal or machine that usually moves in a quadrupedal manner is known as a quadruped, meaning "four feet"...
, an adult Jainosaurus would have measured around eighteen metres long and held its head six metres high. No accurate estimate of the weight has yet been made. The humerus of the type specimen is 134 centimetres long.
Wilson e.a. concluded that Jainosaurus is a valid taxon, clearly distinguishable from Isisaurus
Isisaurus
Isisaurus is a genus of dinosaur from the Late Cretaceous Period. Isisaurus was a sauropod , which lived in what is now India....
. It would have been a fairly derived member of the Titanosauria, more closely related to South-American forms like Pitekunsaurus
Pitekunsaurus
Pitekunsaurus is a genus of titanosaurian sauropod dinosaur from the Late Cretaceous of Neuquén, Argentina. It was described by L. Filippi and A. Garrido in 2008. The type species is P. macayai...
, Muyelensaurus
Muyelensaurus
Muyelensaurus is a genus of titanosaurian sauropod dinosaur from the Late Cretaceous of Argentina. It was more slender than other titanosaurs. Fossils have been recovered from the Neuquén province in Patagonia. The type species is M. pecheni...
and Antarctosaurus
Antarctosaurus
Antarctosaurus is a genus of titanosaurian sauropod dinosaur from the Late Cretaceous Period of what is now South America. The type species, A. wichmannianus, was described by prolific German paleontologist Friedrich von Huene in 1929, who also described a second species in 1929. Three additional...
than to Isisaurus or Rapetosaurus
Rapetosaurus
Rapetosaurus is a genus of sauropod dinosaur that lived in Madagascar from 70 to 65 million years ago, at the end of the Cretaceous Period. Only one species Rapetosaurus is a genus of sauropod dinosaur that lived in Madagascar from 70 to 65 million years ago, at the end of the Cretaceous Period....
.