Hadrosaurus

Hadrosaurus holds a historic place in palaeontology as the first reasonably complete dinosaur skeleton ever excavated in North America. Unearthed in Haddonfield, New Jersey, in 1858, its limb proportions revealed that dinosaurs were not clumsy four-legged lizard-like reptiles as previously envisioned, but bipedal or facultatively quadrupedal animals. Named by Joseph Leidy, Hadrosaurus became the namesake for the entire duck-billed dinosaur family, Hadrosauridae. Reaching an estimated seven to eight metres in length, it was an herbivore adapted to grinding coastal plain plants. While the original skeleton lacked a complete skull, subsequent studies indicate it was likely a crestless or low-crested hadrosaurid. Although modern taxonomists continue to debate its exact evolutionary position relative to better-known western genera, Hadrosaurus remains an iconic milestone in the history of vertebrate palaeontology.

Its discovery in New Jersey provided the first evidence that dinosaurs could walk upright on two legs.

Where and when

Hadrosaurus lived in the Late Cretaceous, from 80.5 to 78.5 million years ago (Campanian age). Its remains come from United States, in the Woodbury Formation.

The numbers

Length 7.5 m (estimates run from 7 to 8 m). Mass about 2.4 t. Hip height about 2.5 m. That is 4.4 human-lengths, or 0.67 of a double-decker bus. These are estimates from partial skeleton; fields marked estimated by the site are length, mass, hip height.

Compare Hadrosaurus with a bus Place on the timeline