Scientific Classification
Kingdom: Animalia
Phylum: Chordata
Class: Sauropsida
Superorder: Dinosauria
Order: Theropoda
Family: Herrerasauridae
Genus: Staurikosaurus

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The Staurikosaurus was one of the earliest dinosaurs to walk the earth, which was discovered in modern times. It was a tiny theropod that was in existence in the middle Triassic period of the Mesozoic era. The timeline of its existence is judged at about 230 to 220 million years ago.
The Staurikosaurus was a carnivorous dinosaur. Its size was about 6 to 7 feet in length. Its weight was about 30 to 35 kilos. Despite of such modest dimensions, the Staurikosaurus was a fierce hunter. It preyed on smaller vertebrates and invertebrates. These features were exponentially magnified in the large theropods of the Jurassic period.
The discovery of the Staurikosaurus was instrumental in understanding the origin of carnivorous dinosaurs. Most of the primitive sauropods discovered before it were herbivorous. The transition between herbivorous to omnivorous to carnivorous dinosaurs was better understood due to Herrerasaurids like the Staurikosaurus.

Nomenclature
The term 'Stauriko' represents the Southern Cross astronomical constellation. This constellation is very lucidly seen from the southern hemisphere.
The term 'sauros' is the Greek word for 'lizard'. Thus, the word 'Staurikosaurus' roughly translates to 'the lizard of the South Cross'.
The binomial name Staurikosaurus pricei is derived from the discoverer of its fossils, Llewellyn Price. This name was coined by paleontologist Edwin Colbert.

Classification
Due to the Staurikosaurus being a primitive dinosaur, its classification was difficult as not many dinosaur species were available to compare the fossils with.

• The Staurikosaurus was presumed to be a simple theropod by the paleontologist Benedetto.
• It was classified as a basal sauropod by Sereno and his colleagues when they first examined it. But prosauropods are herbivorous and the judging by the teeth of the Staurikosaurus, it definitely was not.
• More recent studies by Sues have corroborated Benedetto's initial evaluation that the Staurikosaurus is a theropod dinosaur belonging to family Herrerasauridae.

Discovery of fossils

• The fossils of the Staurikosaurus were initially excavated by scientist L. I. Price way back in 1936. They were discovered in the Jazigo Cinco region of the Santa Maria formation of Brazil.
• Another partial skeleton was uncovered from the Ischigualasto Formation in Argentina that is attributed to the Staurikosaurus.
• Few remains excavated from the Elliot Formation in South Africa that are also believed to belong to the Staurikosaurus.
• Certain fossils derived from the southern region of North America are also considered to possibly belong to the Staurikosaurus.

Africa and South America was a single continent in the Triassic period. Thus many overlapping fossils are found in these regions. It is also very possible for related dinosaurs to be developed on separate continents.

Types and nature of fossils discovered
A fairly large number and diagnostically relevant bones were discovered that were attributed to the Staurikosaurus. They included:

• Most of the vertebral column. This was very important in determining the size and musculature of the Staurikosaurus.
• The femur and radial bones. These revealed a lot of information about the height and weight of the creature.
• A well preserved mandible with teeth. The teeth were sharp, jagged and curved backwards. This indicated the feeding habits of the Staurikosaurus.

• The sacrum consisted of two vertebrae. This was an archetypal character of lesser developed dinosaurs. Advanced dinosaurs mostly have three or four sacral vertebrae. A lot of the information about the hands and feet of the Staurikosaurus can be extrapolated from this fact.
• The mandible of the Staurikosaurus could be moved in two different dimensions. This facilitated tearing apart its prey.
• The fingers of the Staurikosaurus were probably adapted for grasping.
• The length of its femur indicated that the Staurikosaurus was a fast sprinter.

Llewellyn Ivor Price
L. I. Price was one of the primary famous paleontologists from Brazil. He was of America origin and taught at the Harvard University.
Price was instrumental in making the name of Brazil recognizable in the paleontology circles. His work has paved the way for contemporary Brazilian scientists like Max Langer.

Physical Characteristics

• The size of the mandible of Staurikosaurus indicated that it had a long snout and a larger sized head.
• It length of the Staurikosaurus was about 2 to 2.5 meters. Its height was about half a meter.
• The Staurikosaurus was a bipedal dinosaur. It could support itself on its hind legs. It was most likely unable to walk if/when its forelegs touched to the ground.
• The Staurikosaurus weighed about 60 to 70 pounds.
• The tail of the Staurikosaurus was very long. It was stout at the base and thin towards the end.

Habits and habitat
The Staurikosaurus was a terrestrial, carnivorous organism. It probably fed on smaller vertebrates and other dinosaurs. It could clasp on to its prey and chew it before swallowing it.
It used speed to catch its target and also run away from its predators.
The Staurikosaurus probably resided in woodlands and forested areas. The dinosaurs that lived in such regions rarely leave complete skeletal fossils in the ground, which was the case with the Staurikosaurus.

Related and coexisting species
The Staurikosaurus was a basal dinosaur. Its features resembled other basal Triassic vertebrates along with dinosaurs.
The Staurikosaurus is believed to be closely related to the Herrerasaurus. Consequently, it could possibly be related to the Caseosaurus and Chindesaurus. As the Herrerasaurus just preceded the Staurikosaurus, some scientists believe that it could have been the ancestor of the Staurikosaurus. In the alternative, they may have had a common ancestor
The Eorapter and the Coelophysis could also have been related to the Staurikosaurus.
Out of these dinosaurs, the Staurikosaurus may have lived alongside the Herrerasaurus and the Caseosaurus.

Concluding notes about the Staurikosaurus
Although dinosaurs were not present in abundance during the time period of the Staurikosaurus, they were significant in forming a strong foundation for the dinosaur dominance to come in the Jurassic period. The features of the Staurikosaurus match those of many other Triassic vertebrates. This displays the complicated and intricate process of evolution during the Norian age, which led to a large number of dinosaurs being seen in the Jurassic period.
The discovery of the Staurikosaurus helped better understand vertebrates like the Spondylosoma.
The Staurikosaurus was amongst the very first dinosaurs to be seen on the earth. Its carnivorous adaptations probably led to evolution of the killer theropods of the Jurassic period like the Tyrannosaurus.