Buriolet (lat.: Buriolestes) is a genus of carnivorous dinosaurs from the suborder Sauropodomorpha (Sauropodomorpha), who lived in the late Triassic period in the territory of modern Brazil. This animal is one of the oldest science representatives of their group. The only famous view is Buriolestes Schultzi.
History of finds and names
In 2009, in the Buriol gorge, near the Brazilian town of San Juan-Do-Polezini, a skeleton of a small dinosaur was found. In 2016, his typical species was described by a large group of local paleontologists led by Sergey Furtado Cabraira, who gave it the name Buriolestes Schultzi.
The generic name Buriolestes is a combination of the surname of the hosts of the gorge, the Buriol family, and the ancient Greek word “λῃστής” (lestès; “robber”), which indicates the predatory lifestyle of the dinosaur. Special epithet Schultzi is given to the animal in honor of the paleontologist Sezar Schulz.
Hooppers, copy No. ULBRA-PVT280, detected in the layer of the Santa Maria formation, whose age is about 230 million years (Kartni tier). It consists of a skeleton with a skull.
The surviving bone material includes the skull (mainly well-preserved lower edge of the skull, frontal and premaxillary bones), lower jaw, hyoid bone, 7 dorsal vertebrae, 3 sacral vertebrae, 42 caudal vertebrae, left shoulder blade, upper left limb without hand, both ilium, both sit bones, left pubic bone and lower left limb.
Dinosaur fossils are part of the collection of the Museum of Natural Sciences of the Lutheran University of Brazil.
Description
The body length of the buriolesta was about one and a half meters with a mass of 20 kg. The authors of the description established one autapomorphy (a unique feature) of the dinosaur: on the inner protruding surface of the upper part of its tibia, there is a process directed backwards.
A very primitive (basal) sign of the buriolest for the sauropodomorph is that its skull is not shortened, but rather elongated.
There is a distinct gap between the hanging premaxillary and maxillary bones, however, according to the authors of the description, this is a consequence of the downward displacement of the premaxillary bone of the fossil skull, while the diastema was absent in the living dinosaur. Nasal openings do not appear to be enlarged.
There are 4 large crooked teeth on the premaxilla. Notches on their leading edge are absent, in contrast to the teeth of the premaxilla of some neoteropods (lat.: Neotheropoda).
Buriolesta had at least 22 teeth on its maxillary bone. They are dagger-shaped and flattened, while for every millimeter of the length of both cutting edges of the teeth there are 6 notches located at right angles to the edge. The front teeth are very large, and the length of the subsequent teeth gradually decreases.
Unlike neoteropods, the posterior margin of the preorbital fenestra of the skull of Buriolesta has a sharp protruding edge. The posterior part of the frontal bone is distinguished by the presence of supratemporal fenestra, which is a typical feature of dinosaurs. At the ends of the lower jaw there are 2 or 3 large through holes.
The plane in which the bases of the large front teeth lie is slightly inclined downward, which is a typical feature of sauropodomorphs. The presence of 3 sacral vertebrae, the last of which lacks vertically rising ribs, is considered a sign that this vertebra has been “taken away” from the caudal spine.
The upper limb has a long humerus: its length is more than 60% of the length of the femur, which is a sign of sauropodomorphs. The deltopectoral ridge accounts for more than 40% of the length of the humeral shaft.
The iliac bone is characterized by a short and high front, while the back of the bone is long with a depression located on its lower edge for attaching a short tailed muscle. The base of the hip joint is straight, which is a basal sign. The trunk of the pubic bone is straight and flat, without an “apron” or “pedicle”.
The head of the femur protrudes above the surface of its trunk, but forms a not quite right angle with it. In the upper part of the outer side of the femur, there is a small small trochanter and a distinct spinous process.
The tibia is slightly longer than the femur. In the lower part of its outer side there is no thickening spiny process. The calcaneus is vertically flattened and has a reduced outgrowth. The third metatarsal is the longest metatarsal bone, which is typical of dinosaurs. Fifth metatarsal expanded upward.
Unlike basal theropods, the last caudal vertebra does not have an elongated anterior articular process.
Classification
The results of cladistic analysis indicate that Buriolestus was the most basal of the representatives of the Sauropodomorph suborder known to science, located on the evolutionary tree even lower than Eoraptor (lat.: Eoraptor).
Power type
Based on its ancient age and basal position, it is assumed that Buriolest was a predator and fed on small vertebrates and amphibious invertebrates. And this should serve as evidence that sauropodomorphs were originally carnivorous and only later became herbivorous.
