Staurikosaurus (Southern cross lizard)
Staurikosaurus (Southern cross lizard)
Named By : Edwin H. Colbert - 1970
Diet : Carnivore
Size : Estimated 2.25 meters long
Type of Dinosaur : Large Theropod
Type Species : S. pricei (type)
Found in : Brazil - Santa Maria Formation
When it Lived : Late Triassic, 227-221 million years ago
Staurikosaurus (Pronounced “STORE-ee-koh-SAWR-us”, “Southern Cross lizard”) is a genus of herrerasaurid dinosaur from the Late Triassic of Brazil, found in the Santa Maria Formation.
Colbert (1970) explained Staurikosaurus as a small , agile bipedal predator. Staurikosaurus was a predator of the late-Carnian stage and early-Norian that is, the Late Triassic, approximately 225 million years ago. This is one of the oldest dinosaurs to be discovered. With 2.25 meters (7 5 inches) long, and 80 centimetres (31 inches) tall and weighing 30kg (66 lbs), Staurikosaurus was small when compared to theropods of later times like Megalosaurus. The original specimen is an extremely long, but slim bone limbs.
There is a very insufficient fossil evidence of Staurikosaurus comprising the majority part of the spinal column, legs and the huge lower jaw. But, since it is from such an early time in dinosaur’s history and being so primitive, many of Staurikosaurus other characteristics as primitive are able to be reconstructed. For instance, Staurikosaurus is usually depicted with five fingers and five toes that are very basic characteristics of a non-specialized dinosaur. But, as the structure of the legs is well-known and understood, it is evident the fact that Staurikosaurus was a swift runner considering its size. The animal also had only two vertebrae that joined the spine to the pelvis This was a distinct primitive condition.
The teeth available for Staurikosaurus have a morphology that strongly suggests a carnivore’s diet. All of the teeth have serrations, are laterally compressed and caudally bent (i.e. at the tip of each tooth curves towards the mouth). This dentition suggests Staurikosaurus could capture and hold prey as well as cut and tear flesh in order to assist in the process of mechanical digestion.
Staurikosaurus’s tail Staurikosaurus was quite lengthy (with greater than 40 vertebrae) in comparison to the rest of its body . It was straight and free of the ground when it moved. The rear portion of Staurikosaurus’s tail is stiffened due to the features of the vertebrae that form the tail. Ostrom (1969a) believed that this to act as an active stabilizer that facilitates the animal’s running and leaping.
A diagnosis is the description of the anatomical characteristics in an animal (or group) which collectively differentiate it from other species. A few however, not all of the characteristics that are included in a diagnosis may be autapomorphies. A autapomorphy is an characteristic of the anatomical structure that is exclusive to a particular species or group of. As per Sues (1990), Staurikosaurus is distinguished by the following 14 traits that include a mandible nearly equal to the length of the femur, indicating an incredibly large head. an extremely deep, yet thin dentary, with 13-14 teeth, and a well-developed retroarticular system; vertebral column that has the number of cervical vertebrae ranging from 9-10 vertebrae, 15 dorsal, two sacral, and over 40 vertebrae caudalis. Staurikosaurus is thought to be the most primitive of any other dinosaur due to the fact that there are only 2 sacral vertebrae that exist with an extended 3rd 5th and 4th cervical vertebrae that indicate the earliest form of development and cranial cervical vertebrae which are devoid of epipophyses; absence of intervertebral articulations with an accessory as well as a thin blade on the scapular which isn’t expanding proximally; a massive and plate-like coracoid; and a the humerus with prominent deltopectoral and humeral crests (represents an early stage) and also having distinct extended articular ends; and an ilium that has a highly developed medial wall that is an acetabulum that is semiperforated (like Herrerasaurus, but unlike any other dinosaur) and a pubis that is long that is two-thirds long, which is the same length as the femur. hollow limb bones with relatively large walls; a strong femur, with an S-shaped shaft; and a fibula and tibia slightly larger in comparison to the femur. Novas (1993) stated that Staurikosaurus is distinct from other dinosaurs by its distal bevel along the an anterior portion of its pubis. Langer as well as Benton (2006) pointed out that Staurikosaurus can be distinguished on the trochanter’s anterior part being reduced to the form of a scar. Bittencourt Kellner and Kellner (2009) have also observed that the fibula’s proximal region is characterized by a medial sulcus that is only found in Staurikosaurus pricei.