Kileskus

Kileskus
Diagram of the skeleton, known parts are shown.
Temporal occurrence
Middle Jurassic ( Bathonium )
168.3 to 166.1 million years
Locations
western Siberia, Russia ( Itat formation )
Systematics
Lizard dinosaur (Saurischia) Theropoda Coelurosauria Tyrannosauroidea Proceratosauridae Kileskus
Scientific name
Kileskus
Averianov et al. , 2010
Art
Kileskus aristotocus

Kileskus is a genus of theropod dinosaur from the group of the Tyrannosauroidea . So far only fragmentary jaw bones and bones of the fingers and the foot are known, which were found in western Siberia in Russia and come from the Middle Jurassic ( Bathonium ). This makes it one of the oldest known representatives of the Tyrannosauroidea and the parent group Coelurosauria .

Kileskus was first scientifically described in 2010 by Averianov and colleagues with the only species, Kileskus aristotocus . These researchers assign Kileskus to the Proceratosauridae , a group within the Tyrannosauroidea, which also includes the genera Guanlong and Proceratosaurus .

features

Kilescus in size comparison with a human

The Proceratosauridae are characterized by a conspicuous crest of the skull, the presence of which at Kileskus, however - due to the very fragmentary remains - cannot be confirmed. However, since the other two representatives of the Proceratosauridae showed a comb, the researchers suspect such a comb in Kileskus (principle of phylogenetic clasps).

In the paired intermaxillary bone (premaxillary), a bone in front of the upper jaw, there were four teeth each; 17 teeth each were located in the approximately 29 cm long upper jaw. This distinguishes Kileskus from Proceratosaurus , which each had 22 teeth in the upper jaw. The course of an upwardly oriented bone ridge on the upper jaw was unique among related genera.

Find and naming

The fossils include a fragmentary right upper jaw ( holotype , specimen number ZIN PH 5/117), a left intermaxillary bone, a fragment of a left surangular (a bone of the lower jaw), a metacarpal bone, a phalanx, two metatarsals, a toe bone and a foot claw .

These fossils - discovered in the Berezovsk quarry in the Sharypovo district in the Krasnoyarsk region in western Siberia - were found spread over an area of ​​1 to 2 square meters. They come from the gray clays of the upper Itat formation , whose diverse vertebrate fauna includes dinosaurs, pterosaurs, crocodiles, turtles, lizards and various mammals.

The name Kileskus comes from the Khakass language and means "lizard". The second part of the species name, aristotocus , ( ancient Greek άριστότοκος, - "of sublime origin") indicates the systematic position within the advanced theropod group Coelurosauria.

Systematics

Kileskus is counted as a basal Porceratosauridae . Other genera in this family are Proceratosaurus , Guanlong and Sinotyrannus . The Proceratosauriden are a group of the Tyrannosauroidea , whereby the sister taxon are derived Tyrannosauroidea, which include Dilong and Tyrannosaurus among others .

Tyrannosauroidea	Proceratosauridae  Kileskus  void  Guanlong     Proceratosaurus     Sinotyrannus     derived Tyrannosauroidea (e.g. Dilong , Tyrannosaurus )

Individual evidence

1. ↑ ^{a b c d e f g} Alexey O. Averianov, Sergei A. Krasnolutskii, Stepan V. Ivantsov: A new basal coelurosaur (Dinosauria: Theropoda) from the Middle Jurassic of Siberia. In: Proceedings of the Zoological Institute of the Russian Academy of Sciences. Vol. 314, No. 1, 2010, ISSN  0206-0477 , pp. 42-57, digital version (PDF; 1.03 MB) .
2. ↑ Stephen L. Brusatte, Mark A. Norell , Thomas D. Carr, Gregory M. Erickson, John R. Hutchinson, Amy M. Balanoff, Gabe S. Bever, Jonah N. Choiniere, Peter J. Makovicky , Xing Xu : Tyrannosaur Paleobiology: New Research on Ancient Exemplar Organisms. In: Science . Vol. 329, No. 5998, 2010, pp. 1481–1485, doi : 10.1126 / science.1193304 .