Leaellynasaura

Phylogeny: Dinosauria > Ornithischia > Genasauria > Neornithischia > Cerapoda > Ornithopoda > Iguanodontia > Elasmaria

Overview: One of the most fossil-riche sites in Australia is “Dinosaur Cove”, located near the coast of southern Victoria. Rocks from the site are dated to the Early Cretaceous and contain fossils of a myriad of different dinosaurs and other Mesozoic animals. Many of these fossils are those of small ornithopods, some of which are attributed to the genus Leaellynasaura. The creature was officially described and named back in 1989 by the paleontologists Thomas H. Rich and Patricia A. Vickers-Rich – a married couple best known for their work at Dinosaur Cove. Leaellynasaura was named after their own daughter, Leaellyn, with another more obscure dinosaur called Timimus being named after their son Timothy. The latter genus was also found at Dinosaur Cove and probably belongs to some kind of coelurosaur, though its exact status is debated. Leaellynasaura is known from more, but still fragmentary fossils. Both come from Australia’s Eumeralla Formation, so they had to contend with decently large megaraptoran or allosauroid predators.

The holotype specimen of Leaellynasaura consisted of portions of the skull, but some other skeletal remains found at Dinosaur Cove probably belong to it, though some studies have pointed out we can’t be certain if they’re from the same animal or not. Either way, it was clearly not a very large dinosaur. Length estimates put it at maybe two meters long and light in weight. The creature was a bipedal, low-browsing herbivore with a short, pointed snout. If the known skeletal material does belong to Leaellynasaura, then it had a remarkably long tail for an ornithopod of its size. The southern part of Australia was, in its time, much farther south. Leaellynasaura had to contend with prolonged periods of cold and darkness, even though the world overall was warmer than now. Its tail may’ve been an adaptation for these conditions, used to wrap around itself or its young. The holotype’s eyes were large, which implies decent night vision, though it may not have been fully grown. Leaellynasaura likely belonged to the clade Elasmaria, meaning it belonged to a lineage of mostly small to medium-sized iguanodonts from the southern hemisphere.