Dinosaurs / Cretaceous / Incisivosaurus
Incisivosaurus
Cretaceous in-SY-zih-vo-SAWR-us, “incisor lizard”
Incisivosaurus was a primitive oviraptorosaur discovered in the Early Cretaceous rocks of the Yixian Formation in Liaoning, China. Measuring barely one metre in length, it was about the size of a turkey. Unlike its later, toothless cousins, this basal species possessed teeth, most strikingly a pair of large, rodent-like front incisors that displayed distinct wear facets. These worn dental surfaces, combined with the presence of gastroliths in the stomach region, indicate that Incisivosaurus was adapted for eating plants, seeds, or roots rather than flesh. Preserved plumage in close relatives confirms it was fully feathered, likely sporting insulating down across its body and longer feathers on its arms. Its discovery provided crucial evidence that oviraptorosaurs descended from carnivorous theropods but transitioned to herbivory early in their evolutionary history.
It possessed prominent rodent-like front teeth showing distinctive plant-grinding wear surfaces.
Where and when
Incisivosaurus lived in the Early Cretaceous, from 126 to 125 million years ago (Barremian age). Its remains come from China, in the Yixian Formation.
The numbers
Length 0.9 m (estimates run from 0.8 to 1 m). Mass about 2.8 kg. Hip height about 0.4 m. That is 0.5 human-lengths, or 0.08 of a double-decker bus. These are estimates from partial skeleton; fields marked estimated by the site are length, mass, hip height.