Smallest ornithischian dinosaur

Dinosaurs are split into two fundamental taxonomic orders – the saurischians (lizard-hipped dinosaurs) and the ornithischians (bird-hipped dinosaurs). The smallest known ornithischian dinosaur was Fruitadens, which grew to 75 cm long when adult and weighed no more than 0.8 kg, making it about the size of a domestic cat. A heterodontosaur, it lived in the USA approximately 150 million years ago, during the Late Jurassic Period.