Open Paleo

Brontomerus

Taylor et al., 2011 bron-toe-MEE-russ

From Greek bronte meaning 'thunder' and Greek meros meaning 'thigh'. Full meaning: 'thunder thigh', referring to its enormously muscled thighs.

121.4–100.5 million years ago Aptian–Albian, Early Cretaceous
Early Cretaceous stages

Brontomerus is a genus of camarasauromorph sauropod which lived during the early Cretaceous (Aptian or Albian age, approximately 110 million years ago). It was named in 2011 and the type species is Brontomerus mcintoshi. It is probably a fairly basal camarasauromorph, though the taxon is difficult to resolve due to incompleteness of the material. It is most remarkable for its unusual hipbones, which would have supported the largest thigh muscles, proportionally, of any known sauropod. The specific name is in honor of physicist and North American sauropod expert John Stanton McIntosh.

Diagnosis

  1. Preacetabular lobe 55% of total ilium length, longer than in any other sauropod.
  2. Preacetabular lobe directed anterolaterally at 30° to the sagittal, but straight in dorsal view and vertically oriented.
  3. Postacetabular lobe reduced to near absence.
  4. Ischiadic peduncle reduced to a very low bulge.
  5. Ilium proportionally taller than in any other sauropod, 52% as high as long.

Species

Brontomerus mcintoshi Taylor et al., 2011

Type species

Named for physicist and North American sauropod expert John Stanton McIntosh.

Holotype
OMNH 66430 , Oklahoma Museum of Natural History
Material
Left ilium of a juvenile individual.
Horizon
upper Ruby Ranch Member, Cedar Mountain Formation, Aptian–Albian, Early Cretaceous , 121.4–100.5 million years ago
Locality
Hotel Mesa Quarry, Utah, United States

References

  1. Taylor, M. P.; Wedel, M. J.; Cifelli, R. L. (2011). A New Sauropod Dinosaur from the Lower Cretaceous Cedar Mountain Formation, Utah, USA. Acta Palaeontologica Polonica 56(1): 75-98. Polska Akademia Nauk Instytut Paleobiologii (Institute of Paleobiology, Polish Academy of Sciences). doi:10.4202/app.2010.0073 taylor2011a
  2. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Sauropods. Princeton University Press.

    Source of the hip height estimate.

    jones2026b