This group includes some of the largest land animals known to have ever existed, such as Patagotitan, estimated at 37 m (121 ft) long[15] with a weight of 69 tonnes (76 tons),[16] and the comparably-sized Argentinosaurus and Puertasaurus from the same region.

Another taxon of tiny titanosaurs, Ibirania, lived a non-insular context in Upper Creaceous Brazil, and is an example of nanism resultant from other ecological pressures.

[43] Shunosaurus Mamenchisauridae Turiasauria Rebbachisauridae Dicraeosauridae Diplodocidae Camarasaurus Brachiosauridae Euhelopodidae Titanosauria Titanosaurs are classified as sauropod dinosaurs.

One of the few areas of agreement is that the majority of titanosaurs except Andesaurus and some other basal species form a clade called Lithostrotia, which some researchers consider equivalent to the deprecated Titanosauridae.

[51] Titanosaurus indicus was first named by British paleontologist Richard Lydekker in 1877, as a new taxon of dinosaur based on two caudals and a femur collected on different occasions at the same location in India.

[55] German paleontologist Friedrich von Huene provided a significant revision of Titanosauridae the following year in 1929, where he reviewed the dinosaurs of Cretaceous Argentina, and named multiple new genera.

[7] McIntosh provided a large diagnosis of the family: "dorsals with irregularly shaped pleurocoels and spines directed strongly backward; transverse processes directed dorsally as well as laterally, very robust in shoulder region; a second dorsosacral, its rib fused to ilium; caudals strongly procoelous with a prominent ball on distal end of centrum throughout tail; caudal arches on front half of centrum; sternal plates large; preacetabular process of ilium swept outward to become almost horizontal", but stressed that the relationships of titanosaurids to other sauropod groups couldn't be determined due to a lack of cranial material.

[59] José Bonaparte and Rodolfo Coria in 1993 concluded that a new clade of derived sauropods was necessary because Argentinosaurus, Andesaurus and Epachthosaurus were distinct from Titanosauridae as they possessed hyposphene-hypantrum articulations, but were still very closely related to the titanosaurids.

[60] This was followed up by Upchurch's 1998 study on sauropod phylogenetics, which additionally recovered Phuwiangosaurus and Andesaurus within Titanosauroidea and resolved Opisthocoelicaudia as the sister of Saltasaurus instead of the most basal titanosauroid.

[62] Argentinian paleontologist Jaime Powell published his 1986 thesis in 2003, with revisions to bring his old work up to date, including the addition of more phylogenetics and the recognition of Titanosauria as a clade name.

Less inclusive, Titanosauria was diagnosed by horizontally facing dorsal diapophyses, prominent procoelous anterior caudals, and a ridge on the sternal plates.

Nemegtosaurus and Quaesitosaurus were resolved within Titanosauria for the first time, after being placed in Diplodocoidea by multiple other analyses, because Rapetosaurus provided the first significant titanosaur cranial material with associated postcrania.

[64] American paleontologist Jeff Wilson presented another revision of overall sauropod phylogeny in 2002, resolving strong support for most groups, and a similar result to Upchurch (1998) although with Euhelopus closest to titanosaurs instead of outside Neosauropoda.

Wilson & Upchurch (2003) supported the definition of Salgado et al. (1997) for Titanosauria, since it was oldest and most similar to the original content of the group when named by Bonaparte & Coria (1993).

[7] At the same time as Wilson & Upchurch redescribing the species of Titanosaurus, Saldago (2003) looked over the potential invalidity of the family Titanosauridae and redefined the internal clades of Titanosauria.

[65] Following the clade definitions proposed in previous Salgado studies, Bernardo González-Riga published two papers in 2003 describing new taxa in Titanosauria: Mendozasaurus, and Rinconsaurus (with Jorge O. Calvo).

[67] Rinconsaurus was then included in Aeolosaurini, a clade named the following year by Aldirene Franco-Rosas et al. containing everything closer to Aeolosaurus and Gondwanatitan than Saltasaurus or Opisthocoelicaudia.

Isisaurus Alamosaurus Argentinosaurus Antarctosaurus Opisthocoelicaudia Aegyptosaurus Epachthosaurus Ampelosaurus Magyarosaurus Agustinia Trigonosaurus (="Brazil Series B") Malawisaurus Rapetosaurus Nemegtosaurus Lirainosaurus Rocasaurus "Jabalpur indet."

Quaesitosaurus "Malagasy Taxon B" Neuquensaurus Saltasaurus Carballido et al. (2017) Andesaurus Wintonotitan Malarguesaurus Ruyangosaurus Epachthosaurus Rinconsaurus Muyelensaurus Overosaurus Aeolosaurus maximus Bonitasaura Notocolossus Mendozasaurus Quetecsaurus Futalognkosaurus Puertasaurus Drusilasaura Argentinosaurus Patagotitan Dreadnoughtus Malawisaurus Baurutitan Rapetosaurus Tapuiasaurus Isisaurus Alamosaurus Opisthocoelicaudia Neuquensaurus Saltasaurus

[71] Nemegtosauridae was additionally revised by Hussam Zaher et al. (2011) with the description of Tapuiasaurus, which nested closer to Rapetosaurus than Nemegtosaurus, with all three forming a clade of derived lithostrotians.

The primary focus of the analysis was on the basal titanosauriform taxa, but Titanosauria was defined, as the most recent common ancestor of Andesaurus delgadoi and Saltasaurus loricatus, and all its descendants, although the only autapomorphy of the group recovered was the absence of a prominent ventral process on the scapula.

Eutitanosauria (closer to Saltasaurus than Epachthosaurus) was resolved as a very inclusive clade composed of two distinct branches, one leading to the larger-bodied lognkosaurs and the other to the smaller-bodied saltasaurs.

[79] Philip Mannion and colleagues redescribed Lusotitan in 2013, creating a new analysis of 279 characters drawn from significant previous analyses by Upchurch and Wilson supplemented by other studies.

Unique to Mannion et al., continuous characters were distinguished in a run of the matrix, which resolved almost all of Somphospondyli within Titanosauria because of Andesaurus placing very basal in a large group of Andesauroidea.

No differentiation between continuous and discrete characters was made like performed by Mannion et al. (2013), but a large clade of Andesauroidea was still resolved with implied weights.

[83] Andesaurus Ruyangosaurus Daxiatitan Xianshanosaurus Malawisaurus Tapuiasaurus Nemegtosaurus Aeolosaurus Rapetosaurus Alamosaurus Isisaurus Saltasaurus Opisthocoelicaudia Savannasaurus Diamantinasaurus Epachthosaurus Muyelensaurus Rinconsaurus Pitekunsaurus Antarctosaurus Jainosaurus Vahiny Normanniasaurus Argentinosaurus Futalognkosaurus Mendozasaurus Notocolossus Patagotitan Puertasaurus In the description of Mansourasaurus, Sallam et al. (2017) published a phylogenetic analysis of Titanosauria including the most taxa of any analysis of the clade.

[84] In an updated version of the analysis, with the taxon Mnyamawamtuka added, Gorscak & O'Connor (2019) got similar results, with slightly different relationships within small clades.

[14] Karongasaurus Argentinosaurus Andesaurus Ligabuesaurus Jiangshanosaurus Angolatitan Malarguesaurus Chubutisaurus Wintonotitan Tastavinsaurus Malawisaurus Mnyamawamtuka Tapuiasaurus Normanniasaurus Rinconsaurus Isisaurus Rapetosaurus Muyelensaurus Bonitasaura Gondwanatitan Panamericansaurus Overosaurus Shingopana Trigonosaurus Aeolosaurus Argyrosaurus Diamantinasaurus Patagotitan Paralititan Maxakalisaurus Neuquensaurus Saltasaurus Epachthosaurus Futalognkosaurus Mendozasaurus Atsinganosaurus Notocolossus Rukwatitan Lohuecotitan Nemegtosaurus Lirainosaurus Opisthocoelicaudia Ampelosaurus Mansourasaurus Paludititan Pellegrinisaurus Dreadnoughtus Alamosaurus Baurutitan Fossilized dung associated with late Cretaceous titanosaurids from India has revealed phytoliths, silicified plant fragments, that offer clues to a broad, unselective plant diet.

[23] The huge number of individuals gives evidence of herd behavior, which, along with their armor, could have helped provide protection against large predators such as Abelisaurus.

[97] Examination of the titanosaur's bones revealed what appear to be parasitic blood worms similar to the prehistoric Paleoleishmania but are 10-100 times larger, that seemed to have caused the osteomyelitis.