Dromaeosauridae (Dinosauria: Theropoda) from the Bissekty Formation (Upper Cretaceous: Turonian) of Uzbekistan and the phylogenetic position of Itemirus medullaris Kurzanov, 1976

New theropod (Tetanurae: Avetheropoda) material from the ‘mid’-Cretaceous Griman Greek Formation at Lightning Ridge, New South Wales, Australia

“…An internal structure of the vertebrae consisting of a large number of irregularly shaped chambers delimited by thin septa is termed camellate [86] and is present in some ceratosaurs [87], carcharodontosaurids [75], megaraptorids [51,62], Neovenator [66] and coelurosaurs [88]. However, some [megaraptorid] theropods may also present vertebrae with the plesiomorphic condition of a smaller number of larger chambers with thicker septa, defined as a camerate structure and present predominantly in basal tetanurans [86,89].…”

A new carcharodontosaurian theropod dinosaur occupies apex predator niche in the early Late Cretaceous of Uzbekistan

“…Within the rich and diverse dinosaur fauna of the Bissekty Formation (e.g. [12][13][14][15][16][17][18][19]), our discovery of this predatory theropod Ulughbegsaurus, at 7.5-8.0 m in length and greater than 1000 kg in mass, probably occupied the role of apex predator in this Turonian ecosystem. Although the remains of several predatory theropods are described from the formation (Itemirus medullaris, Paronychodon asiaticus, Richardoestesia asiatica, Timurlengia euotica and Urbacodon sp.…”

“…Although the remains of several predatory theropods are described from the formation (Itemirus medullaris, Paronychodon asiaticus, Richardoestesia asiatica, Timurlengia euotica and Urbacodon sp. [12,14,15,[17][18][19]), these taxa are smaller forms than Ulughbegsaurus. The one tyrannosauroid, Timurlengia, is only 3-4 m long with a body mass of about 170 kg ( [19]: electronic supplementary material, table S2), which is comparable to the tyrannosauroid Xiongguanlong (Aptian-Albian [19]).…”

“…Among the mid-Cretaceous deposits in Asia, the faunal composition of the Bissekty Formation is most comparable to that of the Baynshiree Formation in eastern Mongolia, recently redated to late Cenomanian to Turonian [53]. Both formations produce Ankylosauria, Ceratopsia, Hadrosauroidea, Maniraptora (including giant dromaeosaurids [18,54]), Ornithomimosauria, Titanosauria and Tyrannosauroidea (electronic supplementary material, table S3), although Allosauroidea is currently unknown from the Baynshiree Formation. The similarities between dinosaur faunas of the Bissekty ) with the 95% confidence intervals (dashed lines) shows a negative correlation (R 2 = 0.548), indicating that tyrannosauroids were small when other large predatory theropods were present.…”

“…This well-studied formation has yielded a rich and diverse ecosystem with numerous dinosaurs (including Hadrosauroidea, Ceratopsia, Sauropodomorpha, Ornithomimidae, Dromaeosauridae and Tyrannosauroidea) and other vertebrates (e.g. [12][13][14][15][16][17][18][19]). Our discovery adds to few known Late Cretaceous carcharodontosaurian species from Asiamerica and reveals a previously unknown apex predator among mid-sized predatory tyrannosauroids and dromaeosaurids in the Turonian Bissekty ecosystem.…”