| Eoraptor | |
|---|---|
| |
| An artist's illustration of Eoraptor lunensis | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Sauropsida |
| clade: | Dinosauria |
| Order: | Saurischia |
| Genus: | †Eoraptor Sereno et al., 1993 |
| Species: | †E. lunensis |
| Binomial name | |
| Eoraptor lunensis Sereno et al., 1993 | |
Eoraptor (meaning "dawn thief") is a genus of sauropodomorph dinosaurs. It is widely considered to be one of the worlds earliest dinosaurs. The Eoraptor lived during the late Triassic Period, around 231 to 228 million years ago (mya), and is believed to resemble the ancestor of all dinosaurs. It is known by well-preserved fossil records found in Argentina.
Eoraptor had two different types of teeth, indicating that it ate both small animals and plants.
Description[]
The Eoraptor, was given the name raptor but it has no relations to the Velociraptor or any dromaeosaurids. Like many early dinosaurs, had a relatively small body in comparison to dinosaurs of later periods. It had a thin body that was approximately 1 meter in length when fully developed, and weighed approximately 10 kilograms. A bipedal carnivore, the Eoraptor ran upright on its hind legs, while its forelimbs were only half the length of the hind legs. Each forelimb ended in a five digit hand, with three of the digits ending in large claws that were believed to be used to catch and handle prey. While it was believed to have eaten small animals, due to its like swift speed and sharp claws, the Eoraptor also possessed both herbivorous and carnivorous teeth, leading to possible suggestions that Eoraptor may have been rather omnivorous than once suspected.
Discovery[]
The fossil remains of the Eoraptor were first discovered in 1991 by paleontologist Paul Sereno, in the Ischigualasto Basin located in Argentina. Although the area is now barren as a desert badlands, it was believed to have been a river valley during the late Triassic. The Eoraptor was found in the Ischigualasto Formation, which was also the same foundation in which the other early theropod Herrerasaurus was located. As the Eoraptor lacked the specialized hunting features of the major groups of later carnivorous dinosaurs, such as a sliding joint within the articulation of the lower jaw, which would have been used to hold larger prey, it was determined to be one of the world's earliest dinosaurs in 1993. Further evidence supporting the claim of its age was the fact that only some of the Eoraptor's teeth were curved and serrated, unlike later predators.
Classification[]
As the Eoraptor possessed both herbivorous and carnivorous teeth, as well as five fully developed fingers, it was suggested that the Eoraptor was a more ancient species than even the Herrerasaurus. It is believed that only some prosauropods recently discovered in Madagascar of older age. The Staurikosaurus is considered to be possibly older, but due to its large size, it is expected to be of a later evolutionary period. However, as Staurikosaurus seems to have qualities present in both prosauropods and theropods, similar to Eoraptor's shared herbivorous and carnivorous tendencies, it has led researchers to question Eoraptor's primitive label, as its suggested omnivorous qualities were a key factor in its age deduction.
Paleobiology[]
Eoraptor is thought to have been an omnivore, although its dentition is quite similar to that of Buriolestes, which is considered faunivorous. It was a swift sprinter and, upon catching its prey, it would use claws and teeth to tear the prey apart. Unlike later, carnivorous dinosaurs, it lacked a sliding joint at the articulation of the lower jaw, with which to hold large prey. Furthermore, only some of its teeth were curved and saw-edged, unlike those in the mouths of later theropods. The heterodont dentition of Eoraptor consists of both serrated, recurved teeth in the upper jaw, like the teeth of theropods, and leaf-shaped teeth in the lower jaw, like the teeth of basal sauropodomorphs. Eoraptor had 4 teeth in the premaxilla and 18 teeth in the maxilla, a dental formula not dissimilar to that of Herrerasaurus.
Paleoecology[]
During the Late Triassic period, the Ischigualasto Formation was a volcanically active floodplain covered by forests, with a warm and humid climate, but subject to seasonal variations including strong rainfall. Vegetation consisted of ferns, horsetails, and giant conifers, which formed highland forests along the banks of rivers. Herrerasaurus remains appear to have been the most common among the carnivores of the Ischigualasto Formation. Sereno (1993) noted that Eoraptor was found in "close association" with therapsids, rauisuchians, archosaurs, Saurosuchus and the dinosaurs Herrerasaurus and Pisanosaurus, all of whom lived in its paleoenvironment. Herbivores were represented by rhynchosaurs such as Hyperodapedon; aetosaurs; cynodonts like Probelesodon, kannemeyeriid dicynodonts such as Ischigualastia; and traversodontids such as Exaeretodon. These non-dinosaurian herbivores were much more abundant than early dinosaurs. Dinosaur fossils, including those of Eoraptor only represent approximately 6% of the total sample that has been recovered from the Ischigualasto Formation (Rogers et al., 1993), which suggests that dinosaurs were less numerous than other tetrapods.
In Popular Culture[]
- Dinosaurs on Earth, Then... and Now.
- Ultimate Guide to T-Rex (Briefly)
- Eoraptor is featured in Dinosaur King where instead of having a move card it can transform into many dinosaurs (Saurophaganax, Amargasaurus, Styracosaurus, Stegosaurus, Lambeosaurus and Megaraptor)
- Eoraptor appears in Dinosaur Revolution, where a male saved a female from a Saurosuchus and later had a child that was almost killed several times, but was saved by his parents.
- Eoraptor was also featured in Dinosaur Train. In the app, it is stated as a theropod, whereas in real life, it was a basal dinosaur.
- Eoraptor appears in the game, Fossil Fighters: Champions. Ironically, it’s given white proto-feathers on its head and tail, while also supporting a beard. This is to reflect that Eoraptor was one of the oldest known dinosaurs.
- Eoraptor appears in Dino Dana.
Gallery[]
Eoraptor/Gallery