Temporal range: Early Cretaceous
Rich & Rich, 1989
Leaellynasaura (meaning "Leaellyn's lizard") was a fast-running, plant-eating dinosaur that lived in Australia during the middle Cretaceous Period, roughly 115-110 million years ago. Australia was within the Antarctic Circle during the Cretaceous period, and it had a very long winter.
Leaellynasaura is known from two nearly complete skeletons and two skulls. It is described as an ornithopod. Unlike some other ornithischians, the Leaellynasaura did not have any tendons in its tail. The tail is known for being among the longest of its relatives: it was three times longer than the rest of the whole body. It also has more vertebrae in its tail than any other ornithischians except for some hadrosaurs. It also had large eyes to help it look in the dark winter.
- Federico L. Agnolin, Martın D. Ezcurra, Diego F. Pais and Steven W. Salisbury (2010). "A reappraisal of the Cretaceous non-avian dinosaur faunas from Australia and New Zealand: evidence for their Gondwanan affinities" Journal of Systematic Palaeontology, 8 (2) 
- Herne, M. (2009). "Postcranial osteology of Leaellynasaura amicagraphica (Dinosauria; Ornithischia) from the Early Cretaceous of southeastern Australia." Journal of Vertebrate Paleontology, 29(3): 33A.