Balaur (dinosaur)

Live reconstruction of Balaur Bondoc

• Romania

Balaur is a genus theropod dinosaur from the Late Cretaceous ( Maastrichtian ) of Europe. The only way so far described is the type species Balaur Bondoc (Romanian = stocky dragon).

The genus is one of the Dromaeosauridae, but it shows some previously unknown for this group characteristics. Fossils of the animal were discovered in Romania and are about 72 to 66 million years old.

Fragmentary remains have been known since 1997; a more complete, but skull -less skeleton was discovered in September 2009 by the geologist Matyas Vremir and his family. The genus was described scientifically by Csiki and colleagues 2010. It is the most complete skeleton of a theropod dinosaur from the European Central to Upper Cretaceous.

Features

Balaur was about two meters long. It was built for a Dromaeosauriden unusually heavy and strong; his skeleton is characterized by numerous bones fused together. In addition to the enlarged sickle-shaped claw on the second toe of the foot, which is characteristic of Dromaeosauriden, Balaur had a second sickle claw on the first toe that this could still be widely spread apart. The hand bones and the lower bones of the hind leg were fused strong. Zoltán Csiki speculated that the fused metacarpals for grasping prey may have been too rigid, so Balaur had only hunted with his sickle claw feet proven. Unique to this genus is also the strong rear-facing pool with its enlarged muscle - attachment points for the leg muscles.

System

The first, in 1997 discovered bones were initially mistaken for the remains of a possible caenagnathiden Oviraptorosauriers. A phylogenetic analysis of Csiki and colleagues came to the conclusion that Balaur counts within the Dromaeosauridae to Velociraptorinae, where it is most closely related to Velociraptor, whose sister taxon it forms.

Ecology

Europe was an archipelago in the Upper Cretaceous. Besides Balaur also dwarf ( bovine large ) sauropods and small hadrosaur were found at the site. Probably Balaur was to hunt prey in a position that was bigger than himself

Finds

In 2009, discovered the skeleton ( holotype, specimen number VP.313 EME ) was discovered 2.5 kilometers north of the city of Sebes in Romania on the river Sebes. The rocks of the discovery site belong to lithostratigraphically Sebes lineup, the sorted by poor, coarse-grained conglomerates and pebbly sandstones is dominated. Below the Sebes - formation is the marine Bozeş lineup, above follow unconformably rocks from the middle Miocene. The site, known as the Sebes - Glod -locality, located in the lower third of the formation - about 100 meters above the limit of Bozeş lineup and 450 meters below the Miocene unconformity. Probably the locality can be assigned to the late early Maastrichtian. More fossils of the formation close the mostly very fragmentary remains of other dinosaurs, pterosaurs ( Pterosauria ), turtles, crocodiles and possibly birds with one.

In contrast to these fragmentary remains of the Balaur individual is a partial skeleton, whose bones were located in the discovery part in the anatomical network. The Fund consists of eight vertebrae, the sacrum, which consisted of at least four sacral vertebrae, the standing with the sacrum in the anatomical composite basin including incomplete ilium ( ilium ), pubic bone ( pubis ) and ischial ( ischium ), four caudal vertebrae, two fragmentary shoulder blades ( scapula ) with coracoid ( coracoid ), the full arms and the lower bones of the foot, where the tibiotarsus, the metatarsal and the foot bones of the left foot are preserved in the anatomical network. Skull and cervical vertebrae are entirely absent. The Balaur individual was probably transported by a river as partially rotted corpse before its final embedding, was afterwards for a short time partially in air and partially disassembled.

The second known, in 1997 discovered Fund comes from the about 100 km away in Tuştea - ania Loklalität near the village Tuştea in Hunedoara County. The remains were discovered during one of Dan Grigorescu, a professor from the University of Bucharest, conducted excavation. The site shows reddish, silty mudstones and belongs to Densuş - Ciula - formation whose sediments were deposited in the Maastrichtian to Paleogene possibly the inside. Only the middle layer member of this formation contains fossils of vertebrates; the uppermost layer term is dominated by volcanic deposits such as tuffs and contains only isolated plant fossils in the lower layer member missing fossils throughout. The depositional environment of the layers containing fossils is interpreted as the lower (distal ) part of a flood plain. Among the numerous fossils of the formation are the remains of several dinosaurs, pterosaurs, crocodiles, turtles, frogs and Multituberculaten. She is known mainly for its dinosaur nests and eggs, as well as fossils of newborns who are the Hadrosauriden Telmatosaurus transsylvanicus attributed.

The Balaur Fund ( copy numbers FGGUB R. 1580-1585 ) consists of six elements of the left arm, which were found distributed over a relatively small area. Since there are no duplicates among the bones and all the bones will match in size assumed that they all belonged to the same individual. This individual was about 45 % larger than the type specimen.

First description

• Zoltán Csiki, Mátyás Vremir, Stephen L. Brusatte, Mark A. Norell: An aberrant Iceland - dwelling theropod dinosaur from the Late Cretaceous of Romania. PNASS 107: 15357 doi:. 10.1073/pnas.1006970107