Joanusaurus: Difference between revisions

'''''Joanusaurus''''' is a genus of large Joanusaurid theropod dinosaur that lived 150 to 130 million years ago during the Late Jurassic and Early Cretaceous epoch in modern day [[Levantia]] and [[Sarpedon]] on a supercontinent known as [[Sarpolevantia]]. The name "Joanusaurus" means "[[Joanus de Martigueux|Joanus]]' lizard", named in honour of the founder of [[Yonderre]]. The first fossil remains that could definitively be ascribed to this genus were described in 1878 by [[Yonderian people|Yonderian]] paleontologist [[Thibault d'Avignon]]. As one of the first well-known theropod dinosaurs, it has long attracted attention outside of paleontological circles. ''Joanusaurus'' was a large bipedal predator. Its skull was light, robust and equipped with dozens of sharp, serrated teeth. It averaged 10 meters (33 ft) in length, though fragmentary remains suggest it could have reached over 12 m (39 ft). Relative to the large and powerful hindlimbs, its three-fingered forelimbs were small, and the body was balanced by a long and heavily muscled tail. It is classified as a joanusaurid, a type of carnosaurian theropod dinosaur. The bulk of ''Joanusaurus'' remains have come from Central Levantia's [[Greater Levantine Formation]], with material also known from northern [[Caphiria]]. ''Joanusaurus'' has been the [[Dinosaurs in Yonderre|National Dinosaur of Yonderre]] since 1932.

[[File:Greater Levantine Formation Joanusarus.png|thumb|Locations within the [[Greater Levantine Formation]] (yellow) where ''Joanusarus'' remains have been found, holotype marked with "1"]]

The discovery and early study of ''Joanusarus'' came in 1878 when a friend of the paleontologist [[Thibault d'Avignon]] bought a petrified bone from a curio shop in [[Koop]], [[Yonderre]]. Bones such as this had long been known to the populace of the industrious [[Vollardic Mountains]] and were known as the bones of ancient giants in local folklore. When examined by d'Avignon he recognized it as the ''radius'' bone of a large theropod and tentatively assigned it to the genus ''[[Vollardisaurus]]''. d'Avignon secured funding for an expedition to the [[Vollardic Mountains]] in August of 1878 where, aided by local silver miners, more remains were uncovered. In September of 1878 d'Avignon's expedition uncovered remains of a ''Joanusaurus'' in a disused silver mine. With about 31% of the skeleton present in the form of fragmentary bones including parts of three vertebrae, a rib fragment, a toe bone, and, most useful for later discussions, a near-complete skull, d'Avignon pronounced this to be a new species entirely and gave these remains the formal name ''Joanusaurus davignoni''. The species name means "Joanus' lizard" and is named in honour of [[Joanus de Martigueux]], founder of [[Yonderre]]. The type name ''davignoni'' is named for d'Avignon himself.

Further digs in and around the site of the discovery of the first ''Joanusarus'' revealed more remains of ''Joanusarus'' and ''[[Vollardisaurus]]'', as well as remains of the {{wpl|Sauropoda|sauropod}} [[Makrylaimis]] and smaller fossil matter like fossilized plant matter and coprolites. Later digs around the [[Greater Levantine Formation]] uncovered more remains of the ''Joanusaurus'' including the most complete theropod ever uncovered at the time, a ''Joanusaurus'' named GLJN 203 with an approximate 85% completeness. A new subspecies was discovered in 1931 in [[Great Lime Quarry]], [[Anglei]], by [[Jour & Leon]]. Named ''Joanusaurus angleii'', the new subspecies differs from ''J. davignoni'' in several anatomical details, including a jugal or cheekbone with a straight lower margin.

A 1919 expedition led by [[Yonderre|Yonderian]] paleontologist [[Phillipe d'Everard (paleontologist)|Phillipe d'Everard]] uncovered remains of ''Joanusaurus'' in the Aravera mountains of the [[Caphiria|Caphirian]] province [[Iscasta]]. d'Everard initially viewed the specimen as a subadult ''J. davignoni'', but upon closer inspection it was recategorized as a new subspecies, ''J. iscastae''. ''J. iscastae'' differs from ''J. davignoni'' by its longer snout and smaller physical stature, with the largest known specimen, CJI 209, being 9 meters (30 ft) long as opposed to the the largest ''J. davignoni'', JSNH 432, estimated at 11.6 meters (38 feet) long. Remains of at least 15 individual ''Joanusarus'' specimens have been uncovered in [[Caphiria]] since 1919, the latest, CJHM 594, in 2018.