Open Paleo

Nullotitan

Novas et al., 2019 NOO-lo-TIE-tan

Named in honor of geologist Francisco Nullo, combined with Greek 'titan' (giant); meaning 'Nullo's giant'.

72.2–66.0 million years ago Maastrichtian, Late Cretaceous
Late Cretaceous stages

Nullotitan is an extinct genus of lithostrotian titanosaur dinosaurs from the Late Cretaceous Chorrillo Formation of Santa Cruz Province, Argentina. The genus contains a single species, Nullotitan glaciaris. It was a contemporary of the ornithopod Isasicursor, which was described in the same paper.

Under dispute

Placed within Saltasauroidea as incertae sedis. The describing authors (Novas and colleagues, 2019) did not run a phylogenetic analysis and suspected a colossosaurian affinity on the basis of individual characters, whereas the only cladistic analysis to include it (Cerda and colleagues, 2021) recovered Nullotitan as the sister taxon of Saltasauridae, within Saltasauroidea. It is placed following that analysis, with the describers' colossosaurian suspicion noted.

Diagnosis

  1. Anterior caudal centra notably anteroposteriorly short with transverse diameter duplicating anteroposterior length
  2. Proximal and mid-caudal centra with lateral and ventral surfaces profusely excavated by large blind depressions
  3. Mid-caudal vertebrae with large tabicate fossa below transverse process
  4. All caudal vertebrae centra lacking pneumatization
  5. Mid-caudals with deep ventral longitudinal furrow surrounded by thick longitudinal ridges
  6. Fibula with pronounced sigmoid curvature in anterior or posterior view
  7. Distal tibia end strongly anteroposteriorly compressed and more transversely expanded than other titanosaurs

Species

Nullotitan glaciaris Novas et al., 2019

Type species

From Latin 'glaciaris' meaning 'of ice' or 'icy', referring to the Perito Moreno Glacier, which is visible from the discovery site.

Holotype
MACN-PV 18644, MPM 21542 , Museo Argentino de Ciencias Naturales ‘Bernardino Rivadavia’
Material
Isolated cervical centrum (presumably Cv3), fragmentary cervical rib, dorsal rib fragments, several caudal vertebrae, fragmentary left scapula, proximal and distal femur ends, nearly complete tibia, fibula, and astragalus
Horizon
lower Chorrillo Formation, Maastrichtian, Late Cretaceous , 72.2–66.0 million years ago
Locality
Nullo site, Santa Cruz, Argentina

References

  1. Novas, F.; Agnolin, F.; Rozadilla, S.; Aranciaga Rolando, A.; Brissón Egli, F.; Motta, M.; Cerroni, M.; Ezcurra, M.; Martinelli, A.; D´Angelo, J.; Álvarez-Herrera, G.; Gentil, A.; Bogan, S.; Chimento, N.; García Marsà, J. A.; Lo Coco, G.; Miquel, S.; Brito, F.; Vera, E.; Loinaze, V.; Fernandez, M.; Salgado, L. (2019). Paleontological discoveries in the Chorrillo Formation (upper Campanian-lower Maastrichtian, Upper Cretaceous), Santa Cruz Province, Patagonia, Argentina. Revista del Museo Argentino de Ciencias Naturales 21: 217-293. Museo Argentino de Ciencia Naturales. doi:10.22179/revmacn.21.655 novas2019a
  2. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Sauropods. Princeton University Press.

    Source of the mass and hip height estimates.

    jones2026b
  3. Cerda, I.; Zurriaguz, V. L.; Carballido, J. L.; González, R.; Salgado, L. (2021). Osteology, paleohistology and phylogenetic relationships of Pellegrinisaurus powelli (Dinosauria: Sauropoda) from the Upper Cretaceous of Argentinean Patagonia. Cretaceous Research 128. doi:10.1016/j.cretres.2021.104957

    Conducted phylogenetic analysis including Nullotitan among large sauropodomorphs

    cerda2021a