Jiangxititan is an extinct genus of somphospondylan titanosauriform dinosaur from the Late Cretaceous Nanxiong Formation of China. The genus contains a single species, J. ganzhouensis, known from several articulated vertebrae with ribs. Originally described as a titanosaur, Jiangxititan was later suggested to be a non-titanosaurian somphospondylan.

Discovery and naming

The Jiangxititan holotype specimen, NHMG 034062, was discovered in sediments of the Nanxiong Formation near Tankou Town in Ganzhou City of Jiangxi Province, southern China. The specimen consists of the three posteriormost cervical vertebrae with two cervical ribs, articulated with the first four dorsal vertebrae with three dorsal ribs.

In 2023, Mo et al. described Jiangxititan ganzhouensis as a new genus and species of macronarian sauropod based on these fossil remains. The generic name, "Jiangxititan", combines a reference to the type locality in Jiangxi Province with the word "titan", a common suffix for giant sauropod names, referencing the pre-Olympian gods of Greek mythology. The specific name, "ganzhouensis", references the discovery of the fossil in Ganzhou City.

Classification

Mo et al. (2023) recovered Jiangxititan as a derived member of the titanosaurian clade Lognkosauria, as the sister taxon to Mongolosaurus. The results of their phylogenetic analyses are shown in the cladogram below:

TitanosauriaDiamantinasauria Xianshanosaurus Daxiatitan Australodocus Lithostrotia Malawisaurus Aeolosaurus Rapetosaurus Isisaurus Saltasaurus Opisthocoelicaudia Alamosaurus Epachthosaurus Pitekunsaurus Tapuiasaurus Antarctosaurus Vahiny Jainosaurus Normanniasaurus Rinconsaurus Muyelensaurus Nemegtosaurus Lognkosauria Mendozasaurus Argentinosaurus Futalognkosaurus Patagotitan Notocolossus Puertasaurus Jiangxititan Mongolosaurus
Diamantinasauria
Xianshanosaurus Daxiatitan Australodocus Lithostrotia Malawisaurus Aeolosaurus Rapetosaurus Isisaurus Saltasaurus Opisthocoelicaudia Alamosaurus Epachthosaurus Pitekunsaurus Tapuiasaurus Antarctosaurus Vahiny Jainosaurus Normanniasaurus Rinconsaurus Muyelensaurus Nemegtosaurus Lognkosauria Mendozasaurus Argentinosaurus Futalognkosaurus Patagotitan Notocolossus Puertasaurus Jiangxititan Mongolosaurus
Xianshanosaurus Daxiatitan Australodocus
Xianshanosaurus
Daxiatitan
Australodocus
LithostrotiaMalawisaurus Aeolosaurus Rapetosaurus Isisaurus Saltasaurus Opisthocoelicaudia Alamosaurus Epachthosaurus Pitekunsaurus Tapuiasaurus Antarctosaurus Vahiny Jainosaurus Normanniasaurus Rinconsaurus Muyelensaurus Nemegtosaurus Lognkosauria Mendozasaurus Argentinosaurus Futalognkosaurus Patagotitan Notocolossus Puertasaurus Jiangxititan Mongolosaurus
Malawisaurus
Aeolosaurus Rapetosaurus Isisaurus Saltasaurus Opisthocoelicaudia Alamosaurus Epachthosaurus Pitekunsaurus Tapuiasaurus Antarctosaurus Vahiny Jainosaurus Normanniasaurus Rinconsaurus Muyelensaurus Nemegtosaurus Lognkosauria Mendozasaurus Argentinosaurus Futalognkosaurus Patagotitan Notocolossus Puertasaurus Jiangxititan Mongolosaurus
Aeolosaurus Rapetosaurus Isisaurus Saltasaurus Opisthocoelicaudia Alamosaurus
Aeolosaurus Rapetosaurus
Aeolosaurus
Rapetosaurus
Isisaurus Saltasaurus Opisthocoelicaudia Alamosaurus
Isisaurus
Saltasaurus
Opisthocoelicaudia Alamosaurus
Opisthocoelicaudia
Alamosaurus
Epachthosaurus Pitekunsaurus Tapuiasaurus Antarctosaurus Vahiny Jainosaurus Normanniasaurus Rinconsaurus Muyelensaurus Nemegtosaurus Lognkosauria Mendozasaurus Argentinosaurus Futalognkosaurus Patagotitan Notocolossus Puertasaurus Jiangxititan Mongolosaurus
Epachthosaurus
Pitekunsaurus Tapuiasaurus Antarctosaurus Vahiny Jainosaurus Normanniasaurus Rinconsaurus Muyelensaurus Nemegtosaurus Lognkosauria Mendozasaurus Argentinosaurus Futalognkosaurus Patagotitan Notocolossus Puertasaurus Jiangxititan Mongolosaurus
Pitekunsaurus Tapuiasaurus Antarctosaurus Vahiny Jainosaurus
Pitekunsaurus
Tapuiasaurus Antarctosaurus Vahiny Jainosaurus
Tapuiasaurus
Antarctosaurus Vahiny Jainosaurus
Antarctosaurus
Vahiny Jainosaurus
Vahiny
Jainosaurus
Normanniasaurus Rinconsaurus Muyelensaurus Nemegtosaurus Lognkosauria Mendozasaurus Argentinosaurus Futalognkosaurus Patagotitan Notocolossus Puertasaurus Jiangxititan Mongolosaurus
Normanniasaurus
Rinconsaurus
Muyelensaurus
Nemegtosaurus
LognkosauriaMendozasaurus Argentinosaurus Futalognkosaurus Patagotitan Notocolossus Puertasaurus Jiangxititan Mongolosaurus
Mendozasaurus
Argentinosaurus
Futalognkosaurus
Patagotitan Notocolossus Puertasaurus Jiangxititan Mongolosaurus
Patagotitan
Notocolossus
Puertasaurus Jiangxititan Mongolosaurus
Puertasaurus
Jiangxititan Mongolosaurus
Jiangxititan
Mongolosaurus

A subsequent analysis by Han and colleagues in 2024 recovered Jiangxititan as a non-titanosaurian somphospondylan, in a polytomy with several other basal somphospondylans. Removing Jiangxititan as an unstable operational taxonomic unit in their analyses allowed for increased resolution, with more taxa recovered in the Euhelopodidae. The reduced consensus tree from their phylogenetic analyses is shown in the cladogram below:

TitanosauriformesBrachiosauridae Somphospondyli Astrophocaudia Brontomerus Malarguesaurus Paluxysaurus Angolatitan Chubutisaurus Cloverly titanosauriform Fukuititan Gobititan Jiangxititan Ruixinia Jiangshanosaurus Europatitan Tastavinsaurus Ligabuesaurus Dongbeititan Tangvayosaurus Phuwiangosaurus Qiaowanlong Yongjinglong Euhelopus Huanghetitan spp. Diamantinasauria Titanosauria
Brachiosauridae
SomphospondyliAstrophocaudia Brontomerus Malarguesaurus Paluxysaurus Angolatitan Chubutisaurus Cloverly titanosauriform Fukuititan Gobititan Jiangxititan Ruixinia Jiangshanosaurus Europatitan Tastavinsaurus Ligabuesaurus Dongbeititan Tangvayosaurus Phuwiangosaurus Qiaowanlong Yongjinglong Euhelopus Huanghetitan spp. Diamantinasauria Titanosauria
Astrophocaudia Brontomerus Malarguesaurus Paluxysaurus
Astrophocaudia
Brontomerus Malarguesaurus Paluxysaurus
Brontomerus
Malarguesaurus
Paluxysaurus
Angolatitan Chubutisaurus Cloverly titanosauriform Fukuititan Gobititan Jiangxititan Ruixinia Jiangshanosaurus Europatitan Tastavinsaurus Ligabuesaurus Dongbeititan Tangvayosaurus Phuwiangosaurus Qiaowanlong Yongjinglong Euhelopus Huanghetitan spp. Diamantinasauria Titanosauria
Angolatitan
Chubutisaurus
Cloverly titanosauriform
Fukuititan
Gobititan
Jiangxititan
Ruixinia Jiangshanosaurus
Ruixinia
Jiangshanosaurus
Europatitan Tastavinsaurus
Europatitan
Tastavinsaurus
Ligabuesaurus Dongbeititan
Ligabuesaurus
Dongbeititan
Tangvayosaurus Phuwiangosaurus Qiaowanlong Yongjinglong Euhelopus
Tangvayosaurus Phuwiangosaurus
Tangvayosaurus
Phuwiangosaurus
Qiaowanlong Yongjinglong Euhelopus
Qiaowanlong
Yongjinglong Euhelopus
Yongjinglong
Euhelopus
Huanghetitan spp. Diamantinasauria Titanosauria
Huanghetitan spp.
Diamantinasauria Titanosauria
Diamantinasauria
Titanosauria