Clasmodosaurus (meaning "fragmentary tooth reptile") is a genus of titanosaurian sauropod dinosaur from the Bajo Barreal Formation.[1] It lived during the Late Cretaceous in what is now Argentina. It is known only from three fossilized teeth, and is therefore a tooth taxon. It is a nomen dubium.[2][3]

Temporal range: Late Cretaceous, 97–90 Ma
Scientific classification edit
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Saurischia
Clade: Sauropodomorpha
Clade: Sauropoda
Clade: Macronaria
Clade: Titanosauria
Genus: Clasmodosaurus
Ameghino, 1898
C. spatula
Binomial name
Clasmodosaurus spatula
Ameghino, 1898

The type species, Clasmodosaurus spatula, was described by Argentine paleontologist Florentino Ameghino in 1898. For a long time, these teeth were thought to belong to a theropod. The teeth of Clasmodosaurus spatula were polygonal in cross section rather than round, an unusual trait also found in the titanosaur Bonitasaura salgadoi.[4]


Clasmodosaurus was named by Florentino Ameghino in 1898, but remained largely unknown for decades after its discovery.[5] It was originally considered a sauropod, but Friedrich von Huene suggested that it could be a coelurosaur or synonymous with Loncosaurus, which he considered to be a carnosaur.[6] Like Loncosaurus, its taxonomy remained unclear with it regarded as a theropod on the rare occasions it was mentioned.[6] However, Jaime Powell suggested that it was a dubious genus of sauropod in 1986, an identification which has been accepted since. Like diplodocoids and titanosaurs, it had narrow tooth crowns, and it is typically regarded as a titanosaur like most Late Cretaceous sauropods.[6]


  1. ^ "63.2 Provincia de Chubut, Argentina; 2. Bajo Barreal Formation," in Weishampel, et al. (2004). Page 602.
  2. ^ Upchurch, P.; Barrett, P. M.; Dodson, P. (2004). "Sauropoda". In Weishampel, D. B.; Dodson, P.; Osmólska, H. (eds.). The Dinosauria (2nd ed.). pp. 259–322. ISBN 978-0520254084.
  3. ^ Clasmodosaurus
  4. ^ Gallina, P. A.; Apesteguía, S. (2011). "Cranial anatomy and phylogenetic position of the titanosaurian sauropod Bonitasaura salgadoi". Acta Palaeontologica Polonica. 56 (1): 45–60. doi:10.4202/app.2010.0011.
  5. ^ von Huene F. 1929. Los Saurisquios y ornithisquios del Cretaceo Argentino. Anales del Museo de la Plata.
  6. ^ a b c Powell JE. 2003. Revision of South American titanosaurid dinosaurs: palaeobiological, palaeobiogeographical and phylogenetic aspects. Records of the Queen Victoria Museum 111:1–173.