Equijubus

Equijubus was a primitive hadrosauroid ornithopod from the Early Cretaceous of Gansu Province in northwestern China. The genus name translates to horse mane, derived from the local Chinese name of the finding area, Mazongshan. Found almost intact, the holotype comprises a complete skull with articulated lower jaws along with partial postcranial material. Equijubus measured around seven metres in total body length and weighed roughly one to two tonnes. In evolutionary terms, it holds a pivotal position near the base of Hadrosauroidea. It displays an initial stage in the evolution of the duck-bill dental battery, maintaining single replacement teeth at each position while expanding the grinding surfaces. Capable of moving on all fours or rearing up on its hindquarters, Equijubus browsed on tough vegetation in lush lake basin environments, offering vital insights into the Asian radiation of Cretaceous herbivores.

Equijubus is one of the most basal known members of Hadrosauroidea, clarifying early duck-bill jaw development.

Where and when

Equijubus lived in the Early Cretaceous, from 113 to 105 million years ago (Aptian-Albian age). Its remains come from China, in the Zhonggou Formation.

The numbers

Length 6.5 m (estimates run from 6 to 7 m). Mass about 1.5 t. Hip height about 1.8 m. That is 3.8 human-lengths, or 0.58 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 Equijubus with a bus Place on the timeline