Lesothosaurus

*Lesothosaurus diagnosticus*

***Lesothosaurus*** is an omnivorous ornithischian dinosaur. It was named by paleontologist Peter Galton in 1978, the name meaning "lizard from Lesotho". The genus is monotypic, having only one valid species, *Lesothosaurus diagnosticus*, within the genus.

## Classification

*Lesothosaurus* was originally considered an ornithopod. However, more recent work by Paul Sereno has suggested that it may actually represent one of the most primitive of all known ornithischian dinosaurs. The taxonomic history of *Lesothosaurus* is complex and it has long been confused with *Fabrosaurus*, another small ornithischian from the same locality. In 2005, Richard J. Butler published a new phylogenetic study of ornithischians, in which he proposed that *Lesothosaurus* was a basal member of the clade Neornithischia, which includes pachycephalosaurs, ceratopsians and ornithopods. Alternatively, this dinosaur may be a very early thyreophoran, a member of the group including the armored stegosaurians and ankylosaurians. *Stormbergia* may represent the adult form of *Lesothosaurus*.

## Description

*Lesothosaurus* was a 1 metre (3.3 feet) long, 30 kg (66 lbs) bipedal plant-eater. Its long legs, small arms, and slender tail all suggest that it was a fast runner; it would have resembled a large lizard walking bipedally.Like all ornithischians, the tips of *Lesothosaurus* upper and lower jaws were horny, forming a beaklike structure. Behind the beak were leaf-shaped teeth that lined the jaws, and near the front of the upper jaws were 12 fanglike teeth. Analysis of its teeth has shown that Lesothosaurus sliced up plant material with its beak and was not able to chew its food. The small skull of *Lesothosaurus* was short and flat, with large eye sockets. It had large cavities for the eye and jaw muscles. It had a short, pointed snout, and the lower jaw may have ended in a beak. Its teeth were pointed with grooved edges, and would have been ideal for chewing tough plant matter. The skull was mounted on a short but flexible neck. The hind limbs of *Lesothosaurus* were much longer than the forelimbs, which were quite short with small 'hands'. The hand had four well-developed fingers and a smaller fifth finger. The length of the rear legs indicates *Lesothosaurus* was a fast, agile runner. The distinctive femur has a unique femoral head not seen in other dinosaurs. *Lesothosaurus* lived in the hot, arid conditions of Lesotho and South Africa, during the Early Jurassic. Remains of *Lesothosaurus* have been collected from the Upper Elliot Formation, dating it to the Hettangian to Sinemurian portions of the Early Jurassic.

## JPInstitute.com Description

Lesothosaurus is a very early herbivorous (plant-eating) dinosaur. It was very small compared to the later giant plant-eaters. Not a lot is known about this small dinosaur. Lesothosaurus, being such an early dinosaur, shared the way it looked with early meat-eaters. It was still small enough and light enough that it could walk mostly on its hind legs. It was a small, speedy creature that would eat low-growing plants.

Lesothosaurus is known from some skull and skeleton fragments. It is interesting as a specimen because it developed at the very beginning of the Jurassic period. Fragmentary fossils of a dinosaur that was initially identified as Fabrosaurus are thought to possibly be those of the Lesothosaurus. This material was found in Australia (which was connected to South Africa in the late Triassic) and current thinking is that it is likely the same dinosaur.

## Appearance in other media

### *Jurassic Park*

* *Lesothosaurus* has not appeared physically in any of the Jurassic Park films or novels. However, it does appear as a silhouette on the Holoscape screen in the Innovation Center of Jurassic World and it apparently fell back into extinction after the Isla Nublar Incident of 2015 before Jurassic World: Fallen Kingdom.
* It also appears in *Jurassic Park III: Park Builder* as Herbivores Ones.

## Links

http://web.archive.org/web/20040214165607fw\_/http://www.jpinstitute.com/dinopedia/dinocards/dc\_lesot.html#