Kritosaurus

Kritosaurus was a large Late Cretaceous duck-billed dinosaur found primarily in the San Juan Basin of New Mexico. Named by Barnum Brown in 1910, the genus has had a tangled taxonomic history because the holotype skull lacked the snout and nasal roof. Brown originally reconstructed the skull with a flat profile, but later comparisons with Gryposaurus suggested it possessed an arched nasal crest. Modern research confirms that Kritosaurus had a distinct crest formed by nasal bones rising between the eyes, though differing in specific contours from its northern relatives. Estimated at roughly eight to nine metres long and weighing around three tonnes, Kritosaurus lived alongside ceratopsids and ankylosaurs in a subtropical river system. It relied on vast grinding dental batteries to process fibrous leaves and branches in the lush coastal environment.

Its nasal region was missing when first discovered, leading to decades of confusion with the closely related Gryposaurus.

Where and when

Kritosaurus lived in the Late Cretaceous, from 74.5 to 72 million years ago (Campanian age). Its remains come from United States, in the Kirtland Formation.

The numbers

Length 8.5 m (estimates run from 8 to 9 m). Mass about 3.3 t. Hip height about 2.7 m. That is 5 human-lengths, or 0.76 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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