# Brachiosaurus altithorax

> A giant long-necked sauropod from the Late Jurassic Morrison Formation of Colorado, with forelimbs longer than its hind limbs. The famous mounted skeleton in Berlin belongs to a different genus, Giraffatitan.

- Classification: Dinosauria (clade) > Saurischia (clade) > Sauropodomorpha (clade) > Sauropoda (clade) > Macronaria (clade) > Brachiosauridae (family) > Brachiosaurus (genus) > Brachiosaurus altithorax (species)
- Hip height: 3.8–4.4 m
- Mass: 28.7 t
- Age: 154.8–145 million years ago (Late Jurassic)
- Fossils found in: Morrison Formation (Colorado); United States
- Diet: herbivore
- Described: Elmer S. Riggs, 1903
- In films: Jurassic Park (1993), Jurassic Park III (2001), Jurassic World: Fallen Kingdom (2018)

Canonical page: https://dinodex.club/dinosaurs/brachiosaurus-altithorax
Last updated: 2026-09-27

## Overview

Brachiosaurus altithorax lived in western North America in the Late Jurassic. Elmer Riggs of the Field Columbian Museum found the holotype (FMNH P25107) in 1900 near Grand Junction, Colorado, and named it in 1903, calling it "the largest known dinosaur".

It was a macronarian sauropod with front legs longer than its back legs and a long neck held upwards, giving it a sloping back like a giraffe. Its remains in the Morrison Formation are rare: the holotype is still the best specimen, and it lacks the skull and most of the neck.

Much of what is popularly shown as "Brachiosaurus", including the tall skeleton in the Museum für Naturkunde in Berlin, is based on fossils from Tendaguru, Tanzania, once called Brachiosaurus brancai. Taylor (2009) showed that the two differ in many parts of the skeleton and supported moving the African species to its own genus, Giraffatitan. They should not be mixed up when reading sizes.

## Name meaning

From Greek brachion ("arm") and sauros ("lizard"), for the long forelimbs; altithorax, from Latin altus ("deep, high") and Greek thorax ("chest"), for its deep chest (Riggs 1903).

## Sources

1. Cohen, K. M., Harper, D. A. T., Gibbard, P. L. & Car, N. (2023). International Chronostratigraphic Chart (v2023/09). International Commission on Stratigraphy. https://stratigraphy.org/ICSchart/ChronostratChart2023-09.pdf
2. Paul, G. S. (2016). The Princeton Field Guide to Dinosaurs (2nd edition). Princeton University Press.
3. Riggs, E. S. (1903). Brachiosaurus altithorax, the largest known dinosaur. American Journal of Science (series 4) 15: 299-306.
4. Taylor, M. P. (2009). A re-evaluation of Brachiosaurus altithorax Riggs 1903 (Dinosauria, Sauropoda) and its generic separation from Giraffatitan brancai (Janensch 1914). Journal of Vertebrate Paleontology 29(3): 787-806. https://doi.org/10.1671/039.029.0309

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Cite as: "Brachiosaurus altithorax". DinoDex. https://dinodex.club/dinosaurs/brachiosaurus-altithorax (updated 2026-09-27).