Ornithischia — the bird-hipped dinosaurs that ruled the herbivore niche

When and where

Ornithischia appeared around 200 million years ago in the Late Triassic and persisted until the end-Cretaceous extinction 66 million years ago. Their fossils have been found on every continent, including Antarctica. The clade dominated herbivorous dinosaur niches throughout the Jurassic and Cretaceous, evolving into armoured plates, horned skulls, dome heads, and elongated crested bills.

How we know

British paleontologist Harry Seeley established Ornithischia as one of the two primary dinosaur divisions in 1888, using pelvic anatomy. In ornithischians the pubis bone points backward and downward, parallel to the ischium, giving a bird-hipped appearance. This contrasts with the forward-pointing pubis of Saurischia. Seeley also identified the predentary bone, a unique toothless bone at the front of the lower jaw. The clade includes well-known genera such as Stegosaurus, Triceratops, Iguanodon, and Parasaurolophus.

Source: https://en.wikipedia.org/wiki/Ornithischia

What set it apart

The backward-pointing pubis is the clearest anatomical signature. Ornithischians also carried a predentary bone at the tip of the lower jaw, a structure found nowhere else in dinosaurs. Most members were herbivorous, with small leaf-shaped teeth and cheek pouches for processing plants. Over 134 million years the clade produced an extraordinary range of body plans: the plated Stegosaurus reached 9 metres; the horned Triceratops weighed up to 12 tonnes; the dome-headed Pachycephalosaurus carried skull roofs 25 centimetres thick; and the hollow-crested Parasaurolophus pushed 11 metres in length. No carnivorous ornithischian has ever been confirmed.

For collectors and classrooms

An Ornithischia figure stands in for the most diverse branch of plant-eating dinosaurs. A Triceratops or Stegosaurus model captures the clade's range and illustrates the hip structure that defines the group. Use it alongside Saurischia figures to show students the two great divisions of dinosaur evolution. A hand-painted Schleich Triceratops sits at the centre of most starter collections.

Pick up a detailed Ornithischia model here.