Proceratosauridae is a family

Family (biology)

In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 or clade

Clade

A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...

 of theropod dinosaur

Dinosaur

Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...

s, probably belonging to the tyrannosaur

Tyrannosauroidea

Tyrannosauroidea is a superfamily of coelurosaurian theropod dinosaurs that includes the family Tyrannosauridae as well as more basal relatives. Tyrannosauroids lived on the Laurasian supercontinent beginning in the Jurassic Period...

 lineage. It was first named in 2010 by Oliver Rauhut and colleagues in their re-evaluation of the type genus, Proceratosaurus

Proceratosaurus

Proceratosaurus is a genus of small-sized carnivorous theropod dinosaur from the Middle Jurassic of England. It was originally thought to be an ancestor of Ceratosaurus, due to the similar small crest on its snout...

. Their study supported the idea that Proceratosaurus is a coelurosaur, a tyrannosauroid

Tyrannosauroidea

Tyrannosauroidea is a superfamily of coelurosaurian theropod dinosaurs that includes the family Tyrannosauridae as well as more basal relatives. Tyrannosauroids lived on the Laurasian supercontinent beginning in the Jurassic Period...

, and most closely related to the Chinese tyrannosauroid Guanlong

Guanlong

Guanlong was a genus of proceratosaurid tyrannosauroid dinosaur, one of the earliest known examples of the lineage.-Description and discovery:...

. They defined the clade

Clade

A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...

 containing these two dinosaurs as all theropods closer to Proceratosaurus than to Tyrannosaurus, Allosaurus

Allosaurus

Allosaurus is a genus of large theropod dinosaur that lived 155 to 150 million years ago during the late Jurassic period . The name Allosaurus means "different lizard". It is derived from the Greek /allos and /sauros...

, Compsognathus

Compsognathus

Compsognathus was a small, bipedal, carnivorous theropod dinosaur. The animal was the size of a turkey and lived around 150 million years ago, the early Tithonian stage of the late Jurassic Period, in what is now Europe. Paleontologists have found two well-preserved fossils, one in Germany...

, Coelurus

Coelurus

Coelurus is a genus of coelurosaur dinosaur from the Late Jurassic period . The name means "hollow tail", referring to its hollow tail vertebrae...

, Ornithomimus

Ornithomimus

Ornithomimus is a genus of ornithomimid dinosaur from the Late Cretaceous Period of what is now North America.In 1890 Ornithomimus velox was named by Othniel Charles Marsh on the basis of a foot and partial hand from the Maastrichtian Denver Formation. Another seventeen species have been named since...

, or Deinonychus

Deinonychus

Deinonychus was a genus of carnivorous dromaeosaurid dinosaur. There is one described species, Deinonychus antirrhopus. This 3.4 meter long dinosaur lived during the early Cretaceous Period, about 115–108 million years ago . Fossils have been recovered from the U.S...

. Later studies included the Russian Kileskus

Kileskus

Kileskus is a genus of tyrannosauroid dinosaur known from partial remains found in Middle Jurassic rocks of Krasnoyarsk Krai, Russia. Fossils recovered include the holotype maxilla, a premaxilla, a surangular, and a few bones from the hand and foot. The skull bones are similar to those of...

and the Chinese Sinotyrannus

Sinotyrannus

Sinotyrannus is a genus of large basal proceratosaurid dinosaur, a relative of tyrannosaurids which flourished in North America and Asia during the Jurassic and early Cretaceous periods. Sinotyrannus is known from a single incomplete fossil specimen including a partial skull, from the Early...

in the family.