Sonorasaurus

Sonorasaurus was a mid-sized brachiosaurid sauropod that inhabited what is now southern Arizona during the Early Cretaceous. Discovered in 1994 by geology student Richard Thompson, its fossil remains include incomplete limb bones, ribs, vertebrae, and pelvic fragments. As a brachiosaurid, it possessed noticeably longer forelimbs than hindlimbs, giving it an elevated posture suited for high browsing in the canopy. While smaller than its Jurassic predecessor Brachiosaurus, Sonorasaurus was still substantial, measuring around fifteen metres in total length. Its discovery was significant because brachiosaurids were previously thought to have largely vanished from North America by the middle of the Cretaceous period. In 2018, it was formally recognised as the official state dinosaur of Arizona.

It is one of the youngest known brachiosaurid sauropods from North America and the official state dinosaur of Arizona.

Where and when

Sonorasaurus lived in the Early Cretaceous, from 112 to 99.6 million years ago (Albian age). Its remains come from United States, in the Turney Ranch Formation.

The numbers

Length 16 m (estimates run from 14 to 17 m). Mass about 15 t. Hip height about 4.5 m. That is 9.1 human-lengths, or 1.38 of a double-decker bus. These are estimates from partial skeleton; fields marked estimated by the site are length, mass, first ma, last ma, hip height.

Compare Sonorasaurus with a bus Place on the timeline