Dinosaurs / Cretaceous / Edmontonia
Edmontonia
Cretaceous ed-mon-TOE-nee-uh, “from Edmonton”
Edmontonia was one of the largest and most distinctive nodosaurid ankylosaurs of Late Cretaceous North America. Reaching over six metres in length and roughly three tonnes in body mass, it was built low to the ground with short, robust limbs. Its most striking feature was a series of giant, outward-pointing bony spikes lining its shoulders and neck, which may have served for defence against tyrannosaurs or in shoving contests with rivals. Rows of oval plates covered its back and tail in continuous defensive armor. Lacking a tail club, Edmontonia likely crouched close to the substrate when threatened, protecting its vulnerable soft belly while consuming low vegetation across river floodplains.
It carried massive, sideways-pointing shoulder spikes that split into sharp double tips.
Where and when
Edmontonia lived in the Late Cretaceous, from 76.5 to 69 million years ago (Campanian-Maastrichtian age). Its remains come from Canada and United States, in the Horseshoe Canyon Formation.
The numbers
Length 6.3 m (estimates run from 6 to 6.6 m). Mass about 3 t. Hip height about 1.6 m. That is 3.7 human-lengths, or 0.56 of a double-decker bus. These are estimates from near-complete skeleton; fields marked estimated by the site are length, mass, hip height.