| Guanlong | |
|---|---|
 | |
| Mounted skeleton | |
Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Clade: | Dinosauria |
| Clade: | Saurischia |
| Clade: | Theropoda |
| Superfamily: | †Tyrannosauroidea |
| Family: | †Proceratosauridae |
| Genus: | †Guanlong Xuet al.,2006 |
| Species: | †G. wucaii |
| Binomial name | |
| †Guanlong wucaii Xuet al., 2006 | |
Guanlong (Chinese:冠龍;lit. 'crown dragon') is anextinctgenus ofproceratosauridtyrannosauroiddinosaur from theLate Jurassic (Oxfordian)Shishugou Formation ofChina. It was first described in 2006 by Xu Xing and colleagues, who found it to represent a new taxon related toTyrannosaurus. Two individuals are currently known, consisting of a partially complete adult and a nearly complete juvenile.
Guanlong was discovered in theDzungaria area of China by a joint expedition by scientists from theInstitute of Vertebrate Paleontology and Paleoanthropology andGeorge Washington University, and named byXu Xing and others in 2006.Guanlong comes from the Chinese words for "crown" (Chinese:冠;pinyin:guān) and "dragon" (龍;lóng), referring to the crest. The specific epithet,wucaii (), means "multicoloured" and refers to the colours of rock of the Wucaiwan (五彩灣; 'five-colored bay', 'multicolored bay'), the multi-hued badlands where the creature was found.[1][2]
At present,Guanlong is known from two specimens, one discovered on top of the other, with three other individual theropod dinosaurs, in the Shishugou Formation. Theholotype (IVPP V14531) is a reasonably complete, partially articulated adult skeleton, and was the one on top. Another, immature specimen, theparatype IVPP V14532, is known from fully articulated and nearly complete remains. It was presumed to have been trampled, after death, by the adult. The crest on the skull of the immature specimen is notably smaller and restricted to the forward portion of the snout, while the adult has a larger and more extensive crest. The crests of both specimens are thin, delicate structures that likely served as display organs, possibly for events like mating.[1][2]
Guanlong was a relatively small theropod, reaching 3–3.5 m (9.8–11.5 ft) in length and 125 kg (276 lb) in body mass.[2][3][4] Its fossils were found in theShishugou Formation dating to about 160 million years ago, in theOxfordian stage of theLate Jurassic period,[2] 92 million years before its well-known relativeTyrannosaurus. This bipedalsaurischiantheropod shared many traits with its descendants, and also had some unusual ones, like a large crest on its head. Unlike later tyrannosaurs,Guanlong had three long fingers on its hands. Aside from its distinctive crest, it would have resembled its close relativeDilong, and likeDilong may have had a coat of primitivefeathers.[1]
A 2013 study foundGuanlong to be in a clade with bothProceratosaurus andKileskus. Together they formed the familyProceratosauridae with a clade containingSinotyrannus,Juratyrant andStokesosaurus.[5] However, in 2014 another study was published, instead findingStokesosaurus andJuratyrant outside the family, which only includedGuanlong,Proceratosaurus,Kileskus andSinotyrannus.[6]
Below is a simplifiedcladogram of the later analysis, from Fiorillo & Tykoski, 2014.[6]
In 2024, the describers ofAlpkarakush recoveredDilong and proceratosaurids (Proceratosaurus andGuanlong) outside Tyrannosauroidea based on their phylogenetic analysis.[7]
The age of the two individuals were determined using ahistological analysis. The adult was shown to have matured at 7 years of age, and died at the age of 12. The juvenile died at 6, and was still growing. As the individuals are different ages, it can be seen some of the changes that happened during growth. In the juvenile, the crest is restricted to the snout, which is proportionally shorter. The orbit is also larger, thehand comparatively larger, the lower leg is longer, thepubic bone has a less expanded end, and other features found in more derivedcoelurosaurs and tyrannosauroids.[1]
Guanlong possessed a cranial crest, which may have been used for display. It is similar to those ofDilophosaurus andMonolophosaurus, and like those it was highlypneumatized. However, it was more delicate than in the other genera, and also proportionately larger and more elaborate. Structures inDilophosaurus andMonolophosaurus have also been suggested to be for species recognition, but the more gracile crest ofGuanlong is more likely for display purposes.[1]
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