Xiongguanlong

Xiongguanlong
Temporal range: Early Cretaceous, 112 Ma
↓
Mounted skeleton cast
Scientific classification
Kingdom:Animalia
Phylum:Chordata
Clade:Dinosauria
Order:Saurischia
Suborder:Theropoda
Clade:Tyrannoraptora
Superfamily:†Tyrannosauroidea
Genus:†Xiongguanlong
Li et al., 2010
Type species
†Xiongguanlong baimoensis
Li et al., 2010

Xiongguanlong ("Grand Pass dragon") is a genus of tyrannosauroid dinosaur that lived in the Early Cretaceous of what is now China. The type species is X. baimoensis, described online in 2009 by a group of researchers from China and the United States, and formally published in January 2010. The genus name refers to the city of Jiayuguan, a city in northwestern China. The specific name is derived from bai mo, "white ghost", after the "white ghost castle", a rock formation near the fossil site. The fossils include a skull, vertebrae, a right ilium and the right femur. The rocks it was found in are from the Aptian to Albian stages of the Cretaceous, between 125 and 100 million years ago.[1]

Description

Size compared to a human

Xiongguanlong was a bipedal animal which balanced its body with a long tail, like most other theropods. It was intermediate in size between earlier tyrannosauroids from the Barremian and later tyrannosaurids from the Late Cretaceous, such as Tyrannosaurus, and has been estimated to weigh about 300 kilograms (660 lb). The vertebrae were more robust than in other basal tyrannosauroids, possibly to better support a big skull.[2] The skull had a long muzzle resembling that of Alioramus.[1]

Phylogeny

Artist's impression
Diagram of known elements

The describers concluded that Xiongguanlong split off from the main branch of the Tyrannosauroidea before Appalachiosaurus, being the sister taxon of a clade consisting of Appalachiosaurus and the Tyrannosauridae. It has been found to be closely related to Alectrosaurus.[3]

Below is a cladogram by Loewen et al. in 2013 including most tyrannosauroid species.[3]

Tyrannosauroidea

Proceratosauridae

 

 

Proceratosaurus bradleyi

 
 

Kileskus aristotocus

 
 

Guanlong wucaii

 
 
 

 

Sinotyrannus kazuoensis

 
 

 

Juratyrant langhami

 
 

Stokesosaurus clevelandi

 
 
 
 
 

 

Dilong paradoxus

 
 

 

Eotyrannus lengi

 
 

 

Bagaraatan ostromi

 
 

 

Raptorex kriegsteini

 
 

 

Dryptosaurus aquilunguis

 
 

 

 

Alectrosaurus olseni

 
 

Xiongguanlong baimoensis

 
 
 

 

Appalachiosaurus montgomeriensis

 
 

 

 

Alioramus altai

 
 

Alioramus remotus

 
 
 

Tyrannosauridae

 
 
 
 
 
 
 
 
 
 

See also

References

  1. 1 2 Li, Daqing; Norell, Mark A.; Gao, Ke-Qin; Smith, Nathan D.; Makovicky, Peter J. (2010). "A longirostrine tyrannosauroid from the Early Cretaceous of China". Proceedings of the Royal Society B: Biological Sciences. 277 (1679): 183–190. doi:10.1098/rspb.2009.0249. PMC 2842666. PMID 19386654.
  2. ↑ Livescience: ”T. Rex Relative Fills Evolutionary Gap”, 22-4-2009.
  3. 1 2 Loewen, M.A.; Irmis, R.B.; Sertich, J.J.W.; Currie, P. J.; Sampson, S. D. (2013). Evans, David C, ed. "Tyrant Dinosaur Evolution Tracks the Rise and Fall of Late Cretaceous Oceans". PLoS ONE. 8 (11): e79420. doi:10.1371/journal.pone.0079420. PMC 3819173. PMID 24223179.


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