| Proceratosaurids | |
|---|---|
 | |
| Holotype skull ofProceratosaurus bradleyi (NHMUK PV R 4860) | |
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| Skeleton ofGuanlong | |
Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Clade: | Dinosauria |
| Clade: | Saurischia |
| Clade: | Theropoda |
| Superfamily: | †Tyrannosauroidea |
| Family: | †Proceratosauridae Rauhut, Milner & Moore-Fay, 2010 |
| Type species | |
| †Proceratosaurus bradleyi Woodward, 1910 | |
| Subgroups | |
Proceratosauridae is afamily orclade oftyrannosauroidtheropoddinosaurs from the Middle Jurassic to the Early Cretaceous.
Unlike the advancedtyrannosaurids but similar to primitivetyrannosauroids likeDilong, proceratosaurids were generally small (with the exception of the possible proceratosauridsYutyrannus andSinotyrannus) and had fairly long, three-fingered arms capable of grasping prey. In comparison to other members of Tyrannosauroidea, proceratosaurids can be distinguished by the following features according to phylogenetic analyses by Averianovet al. (2010) and Loewenet al. (2013) :[1][2]
The family belongs or is closely related to thetyrannosaur lineage. It was first named in 2010 by Oliver Rauhut and colleagues in their re-evaluation of thetype genus,Proceratosaurus. Their study supported the idea thatProceratosaurus is a coelurosaur, atyrannosauroid, and most closely related to the Chinese tyrannosauroidGuanlong. They defined theclade containing these two dinosaurs as all theropods closer toProceratosaurus than toTyrannosaurus,Allosaurus,Compsognathus,Coelurus,Ornithomimus, orDeinonychus.[3] Later studies included the RussianKileskus and the ChineseSinotyrannus in the family.[4] By the mid-2010s, Proceratosauridae was considered to includeProceratosaurus,Guanlong,Kileskus,Sinotyrannus, and the generaStokesosaurus,Juratyrant, andDilong previously recognized as non-proceratosaurid tyrannosauroids.[2][5] In their re-evaluation ofProceratosaurus, Rauhutet al. stated that tooth taxa from the Late Jurassic and Early Cretaceous previously assigned to thedromaeosaurid subfamilyVelociraptorinae may instead be proceratosaurid in nature, due to the similarity between the teeth of the two groups and the fact that velociraptorines are otherwise unknown from the fossil record until the Late Cretaceous. This would mean thatNuthetes and other dubious genera are potential proceratosaurids.[3]
Below is the cladogram by Loewenet al. in 2013.[2]
| Proceratosauridae | |
An analysis by Brusatteet al. in 2016 provides bothparsimony andBayesian phylogenetic analyses, withYutyrannus being placed within Proceratosauridae as a sister taxon toSinotyrannus andJuratyrant andStokesosaurus being placed as more advanced tyrannosauroids in each instance. The Bayesian analysis is shown below.[6]
| Proceratosauridae | |
Below is acladogram fromNaish andCau (2022):[7]
In their comprehensive revision of the enigmatic Brazilian coelurosauriansMirischia andSantanaraptor, Delcourt et al. (2025) consistently supported a clade containingDilong,Guanlong,Kileskus andProceratosaurus.Tanycolagreus was grouped with this clade in equal-weight phylogenetic analyses, but was also grouped withMirischia,Santanaraptor andJuratyrant in implied-weight phylogenetic analyses. Unlike previous analyses, they found the Proceratosauridae as early-divergingmaniraptoromorphs outside Tyrannosauroidea.[8]
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