Elaphrosaurus (Lightweight lizard)
Elaphrosaurus (Lightweight lizard)
Named By : Werner Janensch - 1920
Diet : Carnivore
Size : Estimated 6.2 meters long
Type of Dinosaur : Large Theropod
Type Species : E. bambergi (type)
Found in : Tanzania - Tendaguru Formation. Possibly also USA - Morrison Formation
When it Lived : Late Jurassic, 154-151 million years ago
Elaphrosaurus (/e:la:froU’so:r@s/ El-AH-froh–SOR-@s) was a genus containing ceratosaurian dinosaurs. It lived between 154 and 150 million years ago in Tanzania, Africa. Elaphrosaurus was a small, but well-built member of the group and could reach 6.2m (20 feet) in length. This dinosaur is important morphologically in two ways. It has a long body, but a very short chest for a dinosaur its size. It also has very small hindlimbs compared to its body. This genus appears to be a ceratosaur based on phylogenetic analysis. It is possible that it may be a coelophysoid, but this idea was dismissed. Elaphrosaurus is believed to be a close relative of Limusaurus. It may also have been an unusually beaked ceratosaurian that was either herbivorous, or omnivorous.
The Elaphrosaurus bambergi HMN Gr.S. type specimen 38-44 were found in the Tendaguru Formation, Middle Dinosaur Member. Werner Janensch and I. Salim collected the specimen in the Tendaguru Formation in Tanzania in 1910. The specimen was deposited in gray, green red, and sandy marl during the Kimmeridgian stage, which was approximately 157 million to 152 millions years ago. The Natural History Museum Berlin houses this specimen.
Werner Janensch first described Elaphrosaurus in 1920. The type species is Elaphrosaurus bimbergi. Elaphrosaurus’ genus name derives from the Greek words elaphros, which means “light to bear”, and sauros (sauros), which refers to its high running speed. This name is in honour of Paul Bamberg, an industrialist who provided financial support for the Tendagaru Expeditions.
HMN Gr.S. 38-44 includes 18 presacral vertebrae and 5 sacral vertebrae. There are also 20 caudal verbrae. A pelvic girdle. Janesch refers to two rib fragments and dorsal vertebrae in 1925. He also refers to a manualphalanx that he believes is phalanx II-2. The referred vertebrae have been lost, and the manual phalanx (now phalanx II-1) cannot be considered as Elaphrosaurus. He also mentioned Elaphrosaurus in 1929. Calcite encrustation caused many fractures and bones that were reconstructed with plaster. However, the left scapulocoracoid was severely deformed.
In stratigraphic zones 2 and 4 of the Morrison Formation, a related animal, possibly from the same genus was discovered.  Very few theropod bones have been discovered, with most of them being fragments.
Elaphrosaurus was credited with the discovery of Dinosaur footprints in Niger Republic and Beit Zayit. This assignment is not conclusive.
Elaphrosaurus had a long, slender neck and was long. Elaphrosaurus is largely known from one skeleton, which was almost complete. No skull has been discovered. Theropods were distinguished by its short legs. Paul (1988), noted that Elaphrosaurus was the longest-bodied, shallowest-chested of all the theropods he had ever seen. Elaphrosaurus measured approximately 6.2m (20 feet) in length, was 1.46m (4.8ft) high at the hip and weighed around 210 kg (460lbs). Another estimate put it at 7.5m (24.6ft) long, 2.1m tall (6.9ft) at the hips, and 210kg (460 lbs) in weight. The length of Elaphrosaurus’ tibia (shin bone), measured 608mm. This was significantly longer than its femur, which measured 520mm. And the metatarsals measured 74% more long than the femur. These proportions are also shared by other ornithomimosaurs and likely reflect cursorial habits. The tail was long and had a rare downward bend, which could be unrelated to Taphonomy. The Elaphrosaurus neck was quite long. However, its cervical vertebrae were not covered with epipophyses. Also, it had thin zygapophyses. This suggests that the neck was less flexible than other theropods. It may also have supported a small skull. These characteristics make Elaphrosaurus unlikely to be a predator of large prey. Its close relationship with Limusaurus suggests that it may have been omnivorous, or herbivorous.
A diagnosis is an indication of the anatomical characteristics of an organism or group that collectively distinguish it. Some of the features that are included in a diagnosis can also be autapomorphies. A distinct anatomical feature unique to a particular organism is called an autapomorphy. Rauhut (2000) states that Elaphrosaurus can easily be distinguished by the following characteristics. The cervical vertebrae have thin ventral laminae bordering the posterior plueurocoel ventrally. The ventral margin of the cervical vertebrae is elevated above the mid-height at which the anterior articular facet is highest. The brevis fossa is very widened so that the brevis shelf forms a nearly horizontal lateral flange. The distal end is strongly expanded to become a triangular boot.
Rauhut’s 2016 study by Carrano added that Elaphrosaurus can be distinguished by distinct ventrolateral laminae at cervical vertebrae. There are no cervical epipophyses, no cervical vertebrae (unique among abelisauroids), and the distal end metacarpal II is offset ventrally by a distinct step. The proximal metatarsal IV is almost 2.5 times more anteroposteriorly and nearly as wide transversely. If it hastragalus ascending process.