Open Paleo

Ninjatitan

Gallina et al., 2021 NIN-juh-TIE-tan

Named for 'Ninja', a nickname of Argentine paleontologist Sebastian Apesteguia, combined with Latin 'titan' meaning 'giant'; translates as 'Ninja giant'.

137.1–132.6 million years ago Valanginian, Early Cretaceous
Early Cretaceous stages

Ninjatitan is an extinct genus of titanosaurian sauropod dinosaur from the Early Cretaceous (Berriasian-Valanginian age) Bajada Colorada Formation of Argentina. The genus contains a single species, Ninjatitan zapatai, which was named and described in 2021 based on a partial postcranial skeleton discovered in 2014. Its generic name comes from a nickname of Argentine paleontologist Sebastian Apesteguia, and the specific name comes from technician Rogelio Zapata.

Under dispute

Placed within Titanosauria as incertae sedis. Potentially the oldest known titanosaur, Ninjatitan is known from fragmentary remains and its precise position is poorly resolved: the describing authors (Gallina and colleagues, 2021) recovered two hypotheses, a very basal titanosaur or a lognkosaurian, and a later analysis (Pérez Moreno and colleagues, 2023) recovered it within Rinconsauria. Mannion and Carvalho (2026) instead recovered Ninjatitan outside Titanosauria altogether and raised the possibility that its holotype is a chimera. A basal position within Titanosauria is currently favored, as a derived (Late Cretaceous) subfamily placement would be hard to reconcile with its Early Cretaceous age.

Diagnosis

  1. Anterior-middle dorsal vertebra with well-developed lateral and medial centropostzygapophyseal laminae enclosing a marked, deep centropostzygapophyseal fossa
  2. Anterior-middle dorsal vertebra with the medial centropostzygapophyseal lamina dorsally and ventrally widened, extending to contact the dorsal rim of the cotyle
  3. Anterior dorsal vertebra with the medial centropostzygapophyseal lamina delimiting a single fossa in which the neural canal is inset
  4. Anterior-middle dorsal vertebra with a dorsally acuminate neural canal fossa
  5. Middle dorsal vertebra with three keels and two longitudinal shallow grooves on the ventral surface of the centrum

Species

Ninjatitan zapatai Gallina et al., 2021

Type species

Named for Rogelio Zapata, the technician involved in the preparation and recovery of the holotype specimen.

Holotype
MMCH-Pv228 , Museo Municipal ‘Ernesto Bachman’, Villa El Chocón
Material
Incomplete anterior-middle dorsal vertebra, middle dorsal centrum, anterior caudal centra with neural arch bases, complete left scapula, fragmentary distal femur, and nearly complete left fibula.
Horizon
Bajada Colorada Formation, Valanginian, Early Cretaceous , 137.1–132.6 million years ago
Locality
Bajada Colorada locality, Neuquén, Argentina

References

  1. Gallina, P. A.; Canale, J. I.; Carballido, J. L. (2021). The Earliest Known Titanosaur Sauropod Dinosaur. Ameghiniana 58(1). Asociacion Paleontologica Argentina. doi:10.5710/amgh.20.08.2020.3376 gallina2021a
  2. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Sauropods. Princeton University Press.

    Source of the body length and hip height estimates.

    jones2026b
  3. Pérez-Moreno, A.; Otero, A.; Carballido, J. L.; Salgado, L.; Calvo, J. O. (2023). The appendicular skeleton of Rinconsaurus caudamirus (Sauropoda: Titanosauria) from the Upper Cretaceous of Patagonia, Argentina. Cretaceous Research 142: 105389. Elsevier BV. doi:10.1016/j.cretres.2022.105389

    Recovered Ninjatitan within Rinconsauria.

    pérez-moreno2023a
  4. Mannion, P. D.; Carvalho, I. S. (2026). Re-evaluation of the Early Cretaceous titanosauriform sauropod dinosaur Triunfosaurus leonardii from the Triunfo Basin, Brazil: implications for the initial radiations of Somphospondyli and Titanosauria. Zoological Journal of the Linnean Society 207(1). Oxford University Press (OUP). doi:10.1093/zoolinnean/zlag073

    Recovered Ninjatitan outside Titanosauria (a diplodocoid or non-titanosaurian somphospondylan) and raised the possibility that its holotype is a chimera.

    mannion2026a