Temporal range: Late Cretaceous,
|Titanosaurus indicus holotypic distal caudal vertebra
Titanosaurus ( // ; lit. 'titanic lizard') is a dubious genus of sauropod dinosaurs, first described by Richard Lydekker in 1877. It is known from the Maastrichtian (Upper Cretaceous) Lameta Formation of India.
Titanosaurus, literally meaning 'titanic lizard', was named after the mythological Titans.
Titanosaurus was the first Indian dinosaur to be named and properly described, having been recorded for the first time in 1877. The type species, T. indicus, was named in 1877,and the second species, T. blanfordi, was named in 1879. Both species were named by Richard Lydekker. T. indicus and T. blanfordi are 70 million years old.
The holotype vertebrae were discovered during an exploration to Jabalpur in 1828 by Capt William Henry Sleeman of the East India Company army. He was one among many explorations for fossils initially carried out by army personnel, medical doctors and priests who chanced upon them just by being “fairly literate and mobile at the time”. He stumbled across the vertebrae on Bara Simla Hill near a British Army gun carriage workshop while searching for petrified wood. Sleeman, employed by the Bengal Army, regarded the bones as curiosities. He gave two vertebral pieces to surgeon G. G. Spilsbury, who had a practice in Japalpur and who also excavated a bone himself. Spilsbury sent the fossils in 1832 to the antiquarian James Prinsep in Calcutta, who realised that they were fossilised bones and then sent them back to Sleeman.In 1862, Thomas Oldman, the first director of the newly established Geological Survey of India, transferred the vertebrae from Japalpur to Calcutta and added them to the collection of the Indian Museum. There, the bones were studied by the Survey's supervisor, Hugh Falconer, who concluded that they were reptilian bones. After Falconer's death, in 1877, Richard Lydekker described the vertebrae as a new species of reptile known as Titanosaurus indicus.
The known remains of T. indicus were generally considered to be lost and untraceable by the end of the twentieth century; in 2010 Matthew Carrano therefore established a cast based on illustrations Lydekker made in 1877, as a replacement plastotype, with the inventory number NHMUK 40867. However, that turned out to be a bit premature. In the early twenty-first century, Indian paleontologist Dhananjay Mohabey understood that such specimens were lost only because no serious inventory of the collections had been carried out for generations.He therefore started the Study of Late Cretaceous Tetrapod fossils from Lameta Formation project with support from the University of Michigan, with one of the main goals of locating lost specimens. In this context, he and Subhasis Sengupta recovered one of the holotype vertebra on 25 April 2012. It turned out to be in a batch of fossils that had been left behind by Lydekker in 1878 that had been lost up until then, which is why no official inventory number of the GSI had been assigned to it.
Part of the fossils that Lydekker assigned to the type specimen of T. indicus, that formed a series of syntypes, was a 1.5 metres (4.9 ft) long femur that had been excavated at the same location in 1871 or 1872 by Henry Benedict Medlicott - specimen GSI K22/754. In 1933 this was reassigned by Charles Alfred Matley and Friedrich von Huene to Antarctosaurus septentrionalis, which was moved to the new genus Jainosaurus in 1995.
A report in PLOS One published in January 2023 said that 92 titanosaur clutches were found in Dhar District (Madhya Pradesh State in central India). There were 256 eggs in three clutch patterns (viz. circular, combination, linear) that are assignable to six oospecies.
Between 1860 and 1870, geologist William Thomas Blanford had found two sauropod middle caudal vertebrae near Pisdura (one vertebra, GSI 2195, became the type specimen). In 1879, they were named by Lydekker as a second species of Titanosaurus, T. Blanfordi,which according to current rules should be written as Titanosaurus blanfordi. Of the two fossils, making up specimen GSI IM K27 / 501, the second, smaller vertebra was split off by von Huene in 1929 and assigned to Titanosaurus araukanicus (now Laplatasaurus ). Upchurch & Wilson concluded in their 2003 revision that this assignment was unfounded, although there is indeed no evidence beyond their origin that the two vertebrae have anything to do with each other. The large vertebra, strongly procoel, convex in front, is distinguished by a square cross-section, the lack of a trough on the underside and elongated proportions. These features are also found in other titanosaurs, although not found in India – the latter, however, was insufficient reason for Upchurch & Wilson not to speak of a nomen dubium . The holotype vertebrae of T. blanfordi were also missing for years and were rediscovered in 2012 by Dhananjay Mohabey and Subhasis Sengupta at the same location as the holotype of T. indicus.
Wilson and Upchurch (2003) treated Titanosaurus as a nomen dubium ("dubious name") because they noted that the original Titanosaurus specimens cannot be distinguished from those of related animals.
As the type genus of Titanosauria, Titanosaurus at times became a wastebasket taxon for a number of titanosaurs, including those not just from India but also southern Europe, Laos, and South America. Only two among these, however, are currently considered species of Titanosaurus: T. indicus and T. blandfordi, both of which are considered nomina dubia.
Other species formerly referred to this genus include:
Megalosaurus is an extinct genus of large carnivorous theropod dinosaurs of the Middle Jurassic Epoch of southern England. Although fossils from other areas have been assigned to the genus, the only certain remains of Megalosaurus come from Oxfordshire and date to the late Middle Jurassic.
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.
Pelorosaurus is a genus of titanosauriform sauropod dinosaur. Remains referred to Pelorosaurus date from the Early Cretaceous period, about 140-125 million years ago, and have been found in England and Portugal. Thomas Holtz estimated its length at 24 meters.
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.
Jainosaurus is a genus of titanosaurian sauropod dinosaur of India and wider Asia, which lived in the Maastrichtian. 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. The humerus of the type specimen is 134 centimetres long.
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.
Cetiosaurus meaning 'whale lizard', from the Greek keteios/κήτειος meaning 'sea monster' and sauros/σαυρος meaning 'lizard', is a genus of herbivorous sauropod dinosaur from the Middle Jurassic Period, living about 168 million years ago in what is now Britain.
Magyarosaurus is a genus of dwarf sauropod dinosaur from late Cretaceous Period in Romania. It is one of the smallest-known adult sauropods, measuring only 6 m (20 ft) in length and 750–1,000 kg (1,650–2,200 lb) in body mass. The type and only certain species is Magyarosaurus dacus. It has been found to be a close relative of Rapetosaurus in the family Saltasauridae in the sauropod clade Titanosauria in a 2005 study.
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.
Andesaurus is a genus of basal titanosaurian sauropod dinosaur which existed during the middle of the Cretaceous Period in South America. Like most sauropods, belonging to one of the largest animals ever to walk the Earth, it would have had a small head on the end of a long neck and an equally long tail.
Bothriospondylus is a dubious genus of neosauropod sauropod dinosaur. It lived during the Late Jurassic in England, and the type and only species is B. suffossus.
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.
Ornithopsis is a genus of sauropod dinosaur, from the Early Cretaceous of England. The type species, which is the only species seen as valid today, is O. hulkei, which is only known from fragmentary remains, and has been regarded by many authors as dubious.
Compsosuchus is a dubious genus of abelisauroid dinosaur. It lived during the Late Cretaceous in India.
Iuticosaurus is a genus of titanosaur sauropod dinosaur from the Early Cretaceous of the Isle of Wight. Two species have been named: I. valdensis and I. lydekkeri. I. valdensis was found in the Wessex Formation and I. lydekkeri in the younger Upper Greensand.
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.
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.
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.