Scientific Classification
Kingdom: Animalia
Phylum: Chordata
Class: Sauropsida
SuperOrder: Dinosauria
Order: Ornithischia
SubOrder: Cerapoda
Family: Hypsilophodontidae
Genus: Laosaurus

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Laosaurus, as the name implies was a stone lizard or fossil lizard. It was classified under the genre hypsilophodontidae.

• The first species was Laosaurus celer. Laosaurus fossil were first discovered by Othniel Charles Marsh from Oxfordian-Tithonian-age which have been estimated by carbon dating of the rocks found in that area. These fossils have been probably belonging to the Upper Jurassic Formation of Morrison. This formation is located at Wyoming in the year 1878. However it is to be noted that the scientific validity of this genus based on the modern diagnostic equipment utilized in the modern era is till now questionable as the study is entirely based on the study of fragmentary fossils.
• It should also be mentioned that a second species of Laosaurus gracilis at Morrison Formation and a species of Laosaurus minimus from the late cretaceous of Alberta have also been discovered.
• The Morrison Formation was characterized be a semi arid environment with wet and dry seasons as well as with presence of flood plains. The vegetation ranged between conifers to fern savannahs. The Morrison Formation is considered as a rich fossil hunting ground with fossils of both zoological as well as botanical importance. The Laosaurus were however specifically discovered in the stratigraphic zones. The Morrison formation has been home to numerous early mammals like tricodonts, multituberculates, and doconodonts. Ornithischians like Camptosaurus, Stegosaurus & Dryosaurus are also known to come from the Morrison.
• Based on anatomical studies of the fossils experts dubiously believe the basal ornithopods. Actually only a handful of tail and partial vertebra were discovered by Marsh. He thus came to the conclusion that it was a fox like animal. It was not until Peter Galton and Charles Gilmore made a thorough study on the fossil remains that they concluded that the bones were not of any fox but of a dinosaur.
• It was actually Charles Gilmore who announced that the skeleton and broken skull were rather that of an ornithopod but were very small in size. He named this species L. gracilis.

As time passed no other species as such has been reported as of yet from anywhere and Laosaurus has still been a subject of mystery. In fact the vertebras that Gilmore studied were very much similar to lizards and frog.

• Peter Galton in 2007 however pointed out that the femur studied by Gilmore has belonged to Othnielia - a hypsilophodont dinosaur named after Othniel Marsh of US. After proper revaluation, Galton concluded that the Nanosaurus rex femur was not diagnostic. He reassigned the skeleton to L.consors which was based on comparatively more diagnostic material. Further as Laosaurus itself was based on non-diagnostic evidences, Galton then provided L.consors with its own genus ie Othnielosaurus. Hence Othnielia became Othnielosaurus consors. However it should be noted that Othnielia should not be confused with Othnielosaurus. They are practically based on different specimens. On the basis of this study, the skeletons that were studied and described as Othnielia got reassigned to Othnielosaurus. Hence the older name remained only with the femur.

Othniel Charles Marsh is a legend in paleontological history as he has earned distinction in naming the most popular dinosaurs. He had a long career in research funded by his rich uncle. His uncle financed the Peabody Museum of National History at Yale University. Besides his legacy for naming dinosaurs Marsh was best known for his rivalry in ‘Bone wars’. He shared a vicious rivalry with Edward Drinker Cope. This famous rivalry started when Marsh once bluntly informed Edward that he had mistakenly placed the head of an Elasmosaurus skeleton on its tail in place of its neck. This rivalry continued for the next two decades with the two wealthy scientists embarking numerous digs and outclassing one another. In the meantime mankind was gifted by an enriched knowledge on the pre-historic life forms. However it is surprising to see that Marsh is still today dismissed by professionals as an ‘armchair paleontologist’ as he preferred to leave the grunt work to his employees and analyzed many fossils in a very short span of time. Thereby it is understood that his studies have been very prone to mistakes.

An Albertan geological unit has been preserving the dinosaur fossils belonging to upper Cretaceous and late Campanian period. It is here that Gilmore had visited the two famous units. He had concluded here that the fossils were that of Laosaurus.

• Loris Russell however pointed out that Gilmore has been wrong and he tagged it as Laosaurus minimus. He made a point that the dinosaur was very much like a hypsilophodont – an ornithopod belonging to the cretaceous period of past Europe.

Laosaurus has been specifically described the skeletons that have been discovered although till now the skull however is poorly known.

• The Laosaurus fossil is present at Paleontology Museum of Zurich .
• This museum is known to exhibit the world’s most important collection of reptiles from middle Triassic period of almost 250 million years ago.
• These also include the extra-ordinarily well-preserved fossils that are of huge scientific value.
• The fossils from the Alps and North America are so unique that they provide a very in-depth look into the recent changing animal world.
• They also have colorful illustrations of long extinct animals that convey how the animals may have looked.

In-Depth analysis of the fossil suggests that the animal must have been comparatively small. The body length was around 2 meters. It must have weighed around 10 kilograms. Skeletal studies suggest Laosaurus was primarily a bipedal animal with short forelimbs. The hind limbs were characterized by long processes for the attachment of muscles. The forelimbs were short and broad in structure and the fingers were short too. As mentioned earlier the head was small with triangular shaped cheek teeth (the presence of cheek teeth is considered to be of evolutionary importance as they helped the animals to carry food in their cheek while chewing). Laosaurus had thin intercostal plates lying around the ribs and they were believed to be of cartilaginous origin. Laosaurus sp. were fast moving bi-pedaled group of Ornithopods. They were however born very small but in the later stages of life grew considerably into efficient grazers.
Finally it should be mentioned that Galtons reassignment to Othnielosaurus has not yet been so widely accepted. Othniella has been almost indistinguishable as both are almost similarly available throughout the internet. However it is quite interesting to notice the discussions and conversations that have been going on in various websites containing facts on Laosaurus. It can easily fill the entire day of a young paleo enthusiast.