Open Paleo

Bonatitan

Martinelli & Forasiepi, 2004 BO-nuh-TIE-tuhn

Named in honor of Argentine paleontologist José Bonaparte, combined with Greek 'titan' meaning 'giant'. The species name honors Osvaldo Reig.

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

Bonatitan is a genus of titanosaurian dinosaur from the Late Cretaceous Allen Formation of Argentina. It was named in 2004.

Diagnosis

  1. Small paired pits on the frontals
  2. Basisphenoid tubera long and narrow, slightly more than twice as long as wide
  3. Dorsal to middle caudal vertebrae with deep oval to circular pits on both sides of the prespinal lamina
  4. Anterior caudal vertebra with spino-postzygapophyseal and spino-prezygapophyseal laminae
  5. Neural arch of anterior caudals with deep interzygapophyseal fossae with numerous pits
  6. Anterior caudal vertebra with an accessory sub-horizontal lamina extending from the anteroventral portion of the postzygapophysis to the mid-portion of the spino-prezygapophyseal lamina
  7. Anterior caudal vertebra with a prominent axial crest on the ventral surface of the centrum
  8. Posterior ridge on metacarpal IV

Species

Bonatitan reigi Martinelli & Forasiepi, 2004

Type species

Named for the Argentine paleontologist Osvaldo Reig.

Holotype
MACN-PV RN 821 , Museo Argentino de Ciencias Naturales ‘Bernardino Rivadavia’
Material
Braincase, the better preserved of the two known for the species
Notes
Salgado and colleagues restricted the holotype to the braincase under ICZN Article 73.1.5, having found that the elements originally cataloged together came from three individuals of different sizes; the remaining bones became referred material.
Horizon
lower Allen Formation, Maastrichtian, Late Cretaceous , 72.2–66.0 million years ago
Locality
Bajo de Santa Rosa, Río Negro, Argentina

Notable specimens

  • MACN-PV RN 821, MACN-PV RN 1061

    Museo Argentino de Ciencias Naturales ‘Bernardino Rivadavia’ complementary

    Referred material representing four individuals, preserving a second braincase and nearly all known postcranial anatomy of the species, including previously undescribed metacarpals, astragali, sacral ribs, haemal arches and metatarsals.

    Salgado et al. (2014)

References

  1. Martinelli, A.; Forasiepi, A. (2004). Late Cretaceous vertebrates from bajo de Santa Rosa (Allen Formation), Río Negro province, Argentina, with the description of a new sauropod dinosaur (Titanosauridae). Revista del Museo Argentino de Ciencias Naturales 6: 257-265. Museo Argentino de Ciencia Naturales. doi:10.22179/revmacn.6.88 martinelli2004a
  2. Salgado, L.; Gallina, P. A.; Paulina-Carabajal, A. (2014). Redescription of Bonatitan reigi (Sauropoda: Titanosauria), from the Campanian–Maastrichtian of the Río Negro Province (Argentina). Historical Biology 27(5): 525-548. Informa UK Limited. doi:10.1080/08912963.2014.894038

    Reorganized the material into five individuals and recovered Bonatitan outside Saltasaurinae.

    salgado2014a
  3. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Sauropods. Princeton University Press.

    Source of the body length, mass, and hip height estimates.

    jones2026b