Isisaurus

Isisaurus (named after the Indian Statistical Institute[1]) is a genus of dinosaur from the Late Cretaceous Period. Isisaurus was a sauropod (specifically a titanosaur), which lived in what is now India.

Isisaurus
Temporal range: Late Cretaceous, 70 Ma
Isisaurus DB
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Order: Saurischia
Suborder: Sauropodomorpha
Clade: Sauropoda
Clade: Titanosauria
Clade: Lithostrotia
Family: Antarctosauridae
Genus: Isisaurus
Wilson & Upchurch, 2003
Species:
I. colberti
Binomial name
Isisaurus colberti
(Jain & Bandyopadhyay, 1997)
Synonyms

Description

There are two types of sauropod skulls from Maastrichtian India. While Jainosaurus had a broad and flat cranium, the skull of Isisaurus was robust and compact. Additionally, the angle between the occipital bone and occipital condyle is different in the two taxa. In the specimen from Dongargaon it is equal to 120°. The cranium of Isisaurus resembles in that matter the skulls of Diplodocus and Apatosaurus (genera belonging to the Diplodocidae), but the bone modifications are different.[2]

Discovery and Naming

The type specimen of Isisaurus colberti, ISI R 335/1-65, was originally described and named as Titanosaurus colberti by Sohan Lal Jain and Saswati Bandyopadhyay in 1997, the specific name honouring Edwin Harris Colbert,[3][4] but was placed in its own genus, by Wilson and Upchurch, in 2003.[5] It had a short, vertically directed neck and long forelimbs, making it considerably different from other sauropods. The humerus is 148 centimetres long.[3] Based on this specimen, Isisaurus would have grown to about 18 meters (60 feet) in length and weighed about 14,000 kg (15 tons).[6]

Isisaurus is known from much better remains than most titanosaurs. Most of its postcranial skeleton is known. The skeletal material Jain and Bandyopadhyay found between 1984 and 1986 was "in associated and mostly articulated condition;" it included cervical, dorsal, sacral and caudal vertebrae, ribs, pelvis, scapula, coracoid, left forelimb and other bones, though skull, hindlimb and foot bones were missing.[3] The site locality is Dongargaon Hill, which is in a Maastrichtian crevasse splay claystone in the Lameta Formation of India.[4] Dongargaon Hill (20.212318N,79.090709E) is located near Warora, in Chandrapur District, Maharashtra.

Palaeobiology

Fungus in coprolites believed to have been voided by Isisaurus indicate that it ate leaves from several species of tree, since these fungi are known to be pathogens which infect tree leaves.[7]

Paleoecology

Isisaurus lived in the area belonging nowadays to India[8] during the Maastrichtian (which is the uppermost stage of Late Cretaceous epoch).[9] Its remains are the most complete among the Cretaceous dinosaurs known from that region.[10] Khosla et al. (2003) listed the following Indian sauropods:[11]

Wilson et al. (2009) listed only two Indian titanosaurs, Isisaurus and its distant relative, Jainosaurus. Isisaurus and Jainosaurus lived sympatrically in the area of nowadays middle and western India, Isisaurus being also present in the area of western Pakistan.[2]

References

  1. ^ "The 10 Ugliest Dinosaurs". about.com. Retrieved November 15, 2013.
  2. ^ a b Jeffrey A. Wilson, Michael D. D'emic, Kristina A. Curry Rogers, Dhananjay M. Mohabey & Subashis Sen (2009). "A reassesment of the sauropod dinosaur Jainosaurus (="Antarctosaurus") septentrionalis from the Upper Cretaceous of India". Contributions from the Museum of Paleontology, University of Michigan. 32 (2): 17–40. Retrieved 2 September 2018.CS1 maint: Multiple names: authors list (link)
  3. ^ a b c 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.
  4. ^ a b "Isisaurus colberti". Paleobiology Database. Retrieved December 31, 2012.
  5. ^ 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.
  6. ^ Montague J.R. (2006). "Estimates of body size and geological time of origin for 612 dinosaur genera (Saurischia, Ornithischia)", Florida Scientist. 69(4): 243-257.
  7. ^ Sharma, N., Kar, R.K., Agarwal, A. and Kar, R. (2005). "Fungi in dinosaurian (Isisaurus) coprolites from the Lameta Formation (Maastrichtian) and its reflection on food habit and environment." Micropaleontology, 51(1): 73-82.
  8. ^ Wilson, J. A. (2006). "An Overview of Titanosaur Evolution and Phylogeny" (PDF). Actas de las III Jornadas Internacionales sobre Paleontología de Dinosaurios y su Entorno, Salas de los Infantes, Burgos. Retrieved 2 September 2018.
  9. ^ González Riga, Bernardo J. (2005). "Nuevos restos fósiles de Mendozasaurus neguyelap (Sauropoda, Titanosauria) del Cretácico Tardío de Mendoza, Argentina". Ameghiniana. 42.
  10. ^ Jeffrey A. Wilson, Paul C. Sereno, Suresh Srivastava, Devendra K. Bhatt, (2003-08-15). "A New Abelisaurid (Dinosauria, Theropoda) Grom The Lameta" (PDF). Contributions From The Museum of Paleontology. The University of Michigan. 31 (1): 1–42. Retrieved 2 September 2018.CS1 maint: Multiple names: authors list (link)
  11. ^ Khosla, A., V. V. Kapur, P. C. Sereno, J. A. Wilson, G. P. Wilson, D. Dutheil, A. Sahni, M. P. Singh, S. Kumar (2003). "First dinosaur remains from the Cenomanian-Turonian Nimar Sandstone (Bagh Beds), district Dhar, Madhya Pradesh, India" (PDF). Journal of The Palaeontogical Society of India. 48: 115–127. Retrieved 2 September 2018.CS1 maint: Multiple names: authors list (link)
Aeolosaurini

Aeolosaurini is an extinct clade of titanosaurian dinosaurs known from the late Cretaceous period of Argentina and Brazil. Thomas Holtz (2011) assigned Adamantisaurus, Aeolosaurus, Gondwanatitan, Muyelensaurus, Panamericansaurus, Pitekunsaurus and Rinconsaurus to Aeolosauridae. Rodrigo M. Santucci and Antonio C. de Arruda-Campos (2011) in their cladistic analysis found Aeolosaurus, Gondwanatitan, Maxakalisaurus, Panamericansaurus and Rinconsaurus to be aeolosaurids.

Austroposeidon

Austroposeidon is an extinct genus of titanosaurian sauropod dinosaur from the Late Cretaceous Presidente Prudente Formation of Brazil. It contains one species, Austroposeidon magnificus.

Diamantinasaurus

Diamantinasaurus is an extinct genus of non-lithostrotian titanosaurian sauropod from Australia that lived during the early Late Cretaceous, about 94 million years ago. The type species of the genus is D. matildae, first described and named in 2009 by Scott Hocknull and colleagues. Meaning "Diamantina lizard", the name is derived from the location of the nearby Diamantina River and the Greek word sauros, "lizard". The specific epithet is from the Australian song Waltzing Matilda, also the locality of the holotype and paratype. The known skeleton includes most of the forelimb, shoulder girdle, pelvis, hindlimb and ribs of the holotype, and one shoulder bone, a radius and some vertebrae of the paratype.

Epachthosaurus

Epachthosaurus (meaning "heavy lizard") was a genus of dinosaur from the Late Cretaceous. It was a titanosaurid sauropod. Its fossils have been found in Central and Northern Patagonia in South America.

Eusauropoda

Eusauropoda (meaning "true sauropods") is a derived clade of sauropod dinosaurs. Eusauropods represent the node-based group that includes all descendant sauropods starting with the basal eusauropods of Shunosaurus, and possibly Barapasaurus, and Amygdalodon, but excluding Vulcanodon and Rhoetosaurus. The Eusauropoda was coined in 1995 by Paul Upchurch to create a monophyletic new taxonomic group that would include all sauropods, except for the vulcanodontids.Eusauropoda are herbivorous, quadrupedal, and have long necks. They have been found in South America, Europe, North America, Asia, Australia, and Africa. The temporal range of Eusauropoda ranges from the early Jurassic to the Latest Cretaceous periods. The most basal forms of eusauropods are not well known and because the cranial material for the Vulcanodon is not available, and the distribution of some of these shared derived traits that distinguish Eusauropoda is still completely clear.

Gravisauria

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

Jainosaurus

Jainosaurus is a large titanosaurian dinosaur of India and wider Asia, which lived in the Maastrichtian (approximately 68 million years ago). 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.

Jeffrey A. Wilson

Jeffrey A. Wilson also known as "JAW" is a professor of geological sciences and assistant curator at the Museum of Paleontology at the University of Michigan.

His doctoral dissertation was on sauropod evolution and phylogeny, and he has continued this work in cladistic analysis and revision of the group (see e.g. Wilson and Sereno 1994, 1998, Wilson 2005b, and especially Wilson 2002). With Paul Sereno, he defined the clades Macronaria and Somphospondyli (Wilson & Sereno 1998).

Wilson was also involved in the discovery and description of Pabwehshi pakistanensis, the first discovery of decent (diagnostic) Cretaceous crocodylian fossil remains from the Indian subcontinent, in the discovery of Rajasaurus narmadensis, the most completely known theropod dinosaur from India and a member of the family Abelisauridae, description of a number of North African dinosaurs (theropods and sauropods) from Niger, and rediscriptions of the Cretaceous sauropods Titanosaurus colberti (as Isisaurus) and Nemegtosaurus (previously thought to be a diplodocoid, but now recognised as a titanosaur).

His younger brother, Dr. Gregory P. Wilson, studies Mesozoic mammals and is currently an assistant professor in the Department of Biology at the University of Washington, and adjunct curator of vertebrate paleontology at the Burke Museum of Natural History and Culture.

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.

Lameta Formation

The Lameta Formation is a sedimentary rock formation found in Madhya Pradesh, Gujarat, and Maharashtra, India. It is of Maastrichtian age (Upper Cretaceous), and is notable for its dinosaur fossils. Many dubious names have been created for isolated bones, but several genera of dinosaurs from these rocks are well-supported, including the titanosaur sauropod Isisaurus and the abelisaurs Indosaurus, Indosuchus, Laevisuchus, and Rajasaurus.

Lithostrotia

Lithostrotia is a clade of derived titanosaur sauropods that lived during the Early Cretaceous and Late Cretaceous. The group was defined by Unchurch 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.

Lohuecotitan

Lohuecotitan is an extinct genus of titanosaurian sauropod dinosaur which lived during the Late Cretaceous in Spain. The only species known in the genus is Lohuecotitan pandafilandi, described and named in 2016.

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.

Saltasaurinae

Saltasaurinae is a subfamily of titanosaurian sauropods known from the late Cretaceous period of South America, India and Madagascar. They are considered to be the most derived of all sauropods.

Savannasaurus

Savannasaurus is a genus of titanosaurian sauropod dinosaur from the Late Cretaceous of Queensland, Australia, containing one species, Savannasaurus elliottorum, named in 2016 by Poropat et al. The only known specimen was originally nicknamed "Wade". The holotype is held on display at the Australian Age of Dinosaurs museum.

Tangvayosaurus

Tangvayosaurus (meaning "Tang Vay lizard") is a genus of sauropod dinosaur from the Aptian-Albian age Lower Cretaceous Grès Supérior Formation of Savannakhet, Laos. It was a basal somphospondylan, about 15 m long, and is known from the remains of two or three individuals.

Tapuiasaurus

Tapuiasaurus (meaning "Tapuia lizard") is a genus of titanosaur which lived during the Lower Cretaceous period (Aptian age) in what is now Minas Gerais, Brazil. Its fossils, including a partial skeleton with a nearly complete skull, have been recovered from the Quiricó Formation of the São Francisco Basin in Minas Gerais, eastern Brazil. This genus was named by Hussam Zaher, Diego Pol, Alberto B. Carvalho, Paulo M. Nascimento, Claudio Riccomini, Peter Larson, Rubén Juárez Valieri, Ricardo Pires Domingues, Nelson Jorge da Silva Jr. and Diógenes de Almeida Campos in 2011, and the type species is Tapuiasaurus macedoi.

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.

Titanosaurus

Titanosaurus (meaning 'titanic lizard' – named after the mythological Titans, deities of Ancient Greece) is a dubious genus of sauropod dinosaurs, first described by Lydekker in 1877. It is known from the Maastrichtian (Upper Cretaceous) Lameta Formation of India.

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