Cedarosaurus

Cedarosaurus was a medium-sized brachiosaurid sauropod discovered in the Yellow Cat Member of the Cedar Mountain Formation in eastern Utah. Living during the Early Cretaceous, it proves that brachiosaurids persisted in North America well after their Late Jurassic heyday. The holotype preserves a substantial partial skeleton, including vertebrae, ribs, limb elements, and gastroliths. In life, Cedarosaurus had a slenderer, more gracile build than its monumental Jurassic predecessor Brachiosaurus, reaching around fourteen to seventeen metres in length. The discovery of over a hundred polished stomach stones between its ribs provides direct evidence of how these giant herbivores used gastroliths to help grind fibrous vegetation in a muscular gizzard. It shared its habitat with dromaeosaurs, basal iguanodonts, and early nodosaurid ankylosaurs.

More than one hundred polished gastroliths, or stomach stones, were preserved directly inside its rib cage.

Where and when

Cedarosaurus lived in the Early Cretaceous, from 139.8 to 125 million years ago (Barremian age). Its remains come from United States, in the Cedar Mountain Formation.

The numbers

Length 16 m (estimates run from 14 to 17 m). Mass about 12 t. Hip height about 3.5 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.

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