Dilong (帝龍, which means 'emperor dragon') is a genus of basal tyrannosauroid dinosaur.[1] The only species is Dilong paradoxus. It is from the Lower Cretaceous Yixian Formation near Lujiatun, Beipiao, in the western Liaoning province of China.
Dilong dinosaur skull cast replica measures ___ inches long.
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The type specimen is IVPP 14243 (Institute of Vertebrate Paleontology and Paleoanthropology in Beijing), a nearly complete, semi-articulated, skull and skeleton. Referred material includes IVPP 1242, a nearly complete skull and presacral vertebrae, TNP01109 (Tianjin Museum of Natural History), a partial skull, and IVPP V11579, another skull which may belong to D. paradoxus, or to a related species. The type specimen of Dilong was about 1.6 m (5.2 ft) in length, but it is thought to be a juvenile and may have been over 2 m (6.6 ft) long when fully grown.
When Dilong was first described, it was considered one of the earliest and most primitive members of Tyrannosauroidea, the group that includes the later, larger tyrannosaurids such as Tyrannosaurus rex. At least one later study, by Turner and colleagues in 2007, reanalyzed the relationships of coelurosaurian dinosaurs, including Dilong, and found that it was not a tyrannosauroid. Rather, they placed Dilong two steps above the tyrannosauroids in their phylogeny; more advanced than Coelurus, but more primitive than the Compsognathidae.[4] However, other studies continued to find Dilong as a tyrannosauroid, and some (such as Carr & Williamson 2010) found Dilong to fall within Tyrannosauroidea, not among the more advanced coelurosaurs.[5]
Below is a cladogram containing most tyrannosauroids by Loewen et al. in 2013.[6]
In a 2014 study, Dilong was found to be a proceratosaurid.[1] However, in an analysis by Brusatte et al. in 2016, both parsimony and Bayesian phylogenetic analyses placed Dilong outside of Proceratosauridae, as a slightly more advanced tyrannosauroid.[7]