Dinosaurs · Large ornithopod

Protohadros

Say it proh-toh-had-ros. The name means ‘first hadrosaur’.

Protohadros beside a person 1.75 m tall. Ticks mark every metre.Body shape drawn for this site, showing the general build of large ornithopods

Length: 6 m
Diet: Plant-eater
When: Late Cretaceous99 to 94 million years ago
Fossils found in: USA
Named by: Head (1998)
Family tree: Dinosauria › Ornithischia › Ornithopoda › Euornithopoda › Iguanadontia › Euiguanadontia › Dryomorpha › Ankylopollexia › Iguanodontoidea

Where Protohadros sits in the age of dinosaurs.Periods from the ICS chart; dinosaur dates from the Natural History Museum

Large ornithopods. Big plant-eaters that walked on two or four legs, including the duck-billed dinosaurs. See all 36

Lived at the same time

Eolambia · same country
Oryctodromeus · same country
Sauropelta · same country
Nothronychus · same country
Zuniceratops · same country
Achillobator
Buitreraptor
Carcharodontosaurus

Other large ornithopods

Eolambia Late Cretaceous
Aralosaurus Late Cretaceous
Jaxartosaurus Late Cretaceous
Brachylophosaurus Late Cretaceous
Nipponosaurus Late Cretaceous
Tanius Late Cretaceous
Muttaburrasaurus Early Cretaceous
Gryposaurus Late Cretaceous

Source: Protohadros in the Natural History Museum Dino Directory, read 12 November 2026. Sizes are the museum's estimates for a typical adult. "Lived at the same time" lists dinosaurs whose dates overlap, which does not always mean they met.