Brachiosauridae

Brachiosauridae was a clade of sauropods that evolved a body plan similar to modern giraffes. While diplodocids extended their bodies horizontally, brachiosaurids developed vertical reach. They are the only sauropod family with forelimbs consistently longer than their hindlimbs. This anatomical trait gave them an inclined back, allowing their long necks to reach high into the forest canopy. Key members include Brachiosaurus, Giraffatitan (formerly Brachiosaurus brancai), Sauroposeidon, Cedarosaurus, and Europasaurus.

Their skulls were high and arched, featuring large nasal openings positioned at the top. This created the classic "domed" profile associated with the group. Their spatulate, spoon-shaped teeth were well-suited for cropping tougher vegetation than the peg-like teeth of diplodocids. Compared to their relatives, brachiosaurids had shorter, less whip-like tails and necks that were proportionally longer than their bodies.

The family belongs to the broader Macronaria, a group of sauropods characterised by relatively short trunks, large nostrils, and robust limbs. As a distinct family, Brachiosauridae is separate from the camarasaurids and the titanosaurs that became dominant during the Cretaceous.

In the Late Jurassic, brachiosaurids avoided direct competition with other sauropods by feeding at different heights. While Diplodocus and Apatosaurus grazed on low-to-mid-range vegetation, Brachiosaurus could reach conifer crowns 9 m or more above the ground. Tooth-wear and gut content analyses indicate they consumed tough branch tips and whole leaves. Fossil trackways and bonebeds, particularly those of the dwarf species Europasaurus found on a Jurassic-era German island, confirm that these animals lived in herds and were subject to island dwarfing.

• Brachiosaurus altithorax holotype (FMNH P 25107) — Field Museum of Natural History, Chicago.
• Giraffatitan brancai Tendaguru specimens (MB.R.2181) — Museum für Naturkunde, Berlin; the largest mounted dinosaur skeleton in the world.
• Europasaurus holgeri specimens — Lower Saxony, Germany; small-island dwarfed brachiosaurid.
• Sauroposeidon proteles holotype (OMNH 53062) — Sam Noble Oklahoma Museum of Natural History.

The split of Brachiosaurus and Giraffatitan (Taylor 2009) — the African Tendaguru material is now generally considered a separate genus rather than a species of Brachiosaurus. Whether Sauroposeidon belongs in Brachiosauridae or is a basal somphospondylan is debated. The maximum height brachiosaurids could comfortably hold their necks (full vertical vs sub-vertical "alert posture") depends on cardiovascular modelling and remains contested.

Brachiosaurus's appearance in Jurassic Park (1993) — the first dinosaur seen on screen, eating leaves from a tree — is one of the most-cited dinosaur scenes in cinema. The Berlin Giraffatitan mount is one of the most-photographed museum exhibits in the world.

• brachiosaurus
• sauropodomorpha
• diplodocidae

• Taylor, M. P. (2009). A re-evaluation of Brachiosaurus altithorax and its generic separation from Giraffatitan brancai. Journal of Vertebrate Paleontology, 29, 787–806.
• D'Emic, M. D. (2012). The early evolution of titanosauriform sauropod dinosaurs. Zoological Journal of the Linnean Society, 166, 624–671.
• Sander, P. M., et al. (2006). Adaptive radiation in sauropod dinosaurs: bone histology indicates rapid evolution of giant body size. Organisms Diversity & Evolution, 4, 165–173.
• Wedel, M. J., et al. (2000). Sauroposeidon proteles, a new sauropod from the Early Cretaceous of Oklahoma. Journal of Vertebrate Paleontology, 20, 109–114.