Ceratosaurs are members of a group 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 defined as all theropods sharing a more recent common ancestry with Ceratosaurus

Ceratosaurus

Ceratosaurus meaning "horned lizard", in reference to the horn on its nose , was a large predatory theropod dinosaur from the Late Jurassic Period , found in the Morrison Formation of North America, in Tanzania and Portugal...

than with birds. There is presently no universally agreed upon listing of species or diagnostic characters of Ceratosauria, though they were less derived

Derived

In phylogenetics, a derived trait is a trait that is present in an organism, but was absent in the last common ancestor of the group being considered. This may also refer to structures that are not present in an organism, but were present in its ancestors, i.e. traits that have undergone secondary...

 anatomically than the more diverse Tetanurae

Tetanurae

Tetanurae, or "stiff tails", is a clade that includes most theropod dinosaurs, as well as birds. Tetanurans first appear during the early or middle Jurassic Period.-Definition:...

. According to the latest and most accepted theory, Ceratosauria includes the Late Jurassic to Late Cretaceous theropods Ceratosaurus

Ceratosaurus

Ceratosaurus meaning "horned lizard", in reference to the horn on its nose , was a large predatory theropod dinosaur from the Late Jurassic Period , found in the Morrison Formation of North America, in Tanzania and Portugal...

, Elaphrosaurus

Elaphrosaurus

Elaphrosaurus is a genus of theropod dinosaur from the Kimmeridgian stage of the Late Jurassic of Tanzania. Elaphrosaurus was probably a ceratosaur about 6 meters long. Suggestions that it is a late surviving coelophysoid have been entertained but are generally dismissed. It was first...

, and Abelisaurus

Abelisaurus

Abelisaurus is a genus of abelisaurid theropod dinosaur from the Late Cretaceous Period of what is now South America. It was a bipedal carnivore that probably reached 7 to 9 meters in length, although it is known from only one partial skull.The generic name recognizes Roberto Abel as the...

, found primarily (though not exclusively) in the Southern Hemisphere

Southern Hemisphere

The Southern Hemisphere is the part of Earth that lies south of the equator. The word hemisphere literally means 'half ball' or "half sphere"...

. Originally, Ceratosauria included the above dinosaurs plus the Late Triassic to Early Jurassic Coelophysoidea

Coelophysoidea

Coelophysoids were common dinosaurs of the Late Triassic and Early Jurassic periods. They were widespread geographically, probably living on all continents. Coelophysoids were all slender, carnivorous forms with a superficial similarity to the coelurosaurs, with which they were formerly...

 and Dilophosauridae

Dilophosauridae

Dilophosauridae is a family of early carnivorous dinosaurs. They are well-known for their distinctive head crests, which were probably used for mating displays, or to intimidate rivals. The family was proposed by Alan Charig and Andrew Milner in 1990 to contain only the type genus, Dilophosaurus...

, implying a much earlier divergence of ceratosaurs from other theropods. However, most recent studies have shown that coelophysoids and dilophosaurids do not form a natural group

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...

 with other ceratosaurs, and are excluded from this group.

Taxonomy

• Infraorder Ceratosauria
  • Berberosaurus
    Berberosaurus
    Berberosaurus is a genus of abelisauroid theropod dinosaur from the Pliensbachian-Toarcian-age Lower Jurassic Toundoute Continental Series found in the High Atlas of Toundoute, Ouarzazate, Morocco. The type species of the genus Berberosaurus is B. liassicus, in reference to the Lias epoch...
    
    
  • Deltadromeus
    Deltadromeus
    Deltadromeus is a genus of large basal ceratosaurian theropod dinosaur from Northern Africa. It had long, unusually slender hind limbs for its size, suggesting that it was a swift runner. The skull is not known. Two fossil specimens of a single species Deltadromeus (meaning "delta runner") is a...
    
    
  • Elaphrosaurus
    Elaphrosaurus
    Elaphrosaurus is a genus of theropod dinosaur from the Kimmeridgian stage of the Late Jurassic of Tanzania. Elaphrosaurus was probably a ceratosaur about 6 meters long. Suggestions that it is a late surviving coelophysoid have been entertained but are generally dismissed. It was first...
    
    
  • Limusaurus
    Limusaurus
    Limusaurus is a genus of toothless herbivorous theropod dinosaur from the Jurassic Upper Shishugou Formation in the Junggar Basin of western China. Limusaurus is also the first definitely known ceratosaur from Eastern Asia, including China...
    
    
  • ?Lukousaurus
    Lukousaurus
    Lukousaurus is a taxon based on most of a small skull’s snout, displaying distinctive lachrymal horns, found in the Early Jurassic-age Lower Lufeng Formation, Yunnan, China and was described by Chung Chien Young in 1948....
    
    
  • Spinostropheus
    Spinostropheus
    Spinostropheus is a genus of small ceratosaurian dinosaur that lived in the late Jurassic period of Niger. Once thought to be a species closely related to the abelisaurs , subsequent studies have confirmed the original interpretation as a basal ceratosaur closely related to Elaphrosaurus...
    
    
  • Family Bahariasauridae
    • Bahariasaurus
      Bahariasaurus
      Bahariasaurus is a genus of large theropod dinosaur found in the Bahariya Formation in El-Waha el-Bahariya or Bahariya oasis in Egypt and Kem Kem Beds of North Africa, which date to the late Cretaceous Period, , about 95 million years ago...
      
      
  • Neoceratosauria
    • Family Ceratosauridae
      Ceratosauridae
      Ceratosauridae is a family of theropod dinosaurs belonging to the infraorder Ceratosauria. Its type genus, Ceratosaurus, was first found in Jurassic rocks from North America. Ceratosauridae is made up of Ceratosaurus, found in North America, Tanzania, and Portugal, and Genyodectes, from the Late...
      
      
      • Ceratosaurus
        Ceratosaurus
        Ceratosaurus meaning "horned lizard", in reference to the horn on its nose , was a large predatory theropod dinosaur from the Late Jurassic Period , found in the Morrison Formation of North America, in Tanzania and Portugal...
        
        
      • Genyodectes
        Genyodectes
        Genyodectes is a genus of ceratosaurian theropod dinosaur from the Lower Cretaceous of South America. The holotype material was collected from the Cañadón Grande, Departamento Paso de Indios in the Chubut Province of Argentina and consists of an incomplete snout, including the premaxillae,...
        
        
    • Superfamily Abelisaur
      Abelisaur
      Abelisaurs were a group of ceratosaurian dinosaurs which lived in the Southern hemisphere during the Cretaceous period. Some well-known dinosaurs of this group include Abelisaurus, Carnotaurus, and Majungasaurus. They are known for their small arms...
      
      oidea

Phylogeny

The following cladogram

Cladogram

A cladogram is a diagram used in cladistics which shows ancestral relations between organisms, to represent the evolutionary tree of life. Although traditionally such cladograms were generated largely on the basis of morphological characters, DNA and RNA sequencing data and computational...

 follows an analysis by Xu Xing and colleagues, 2009.

External links

• Ceratosauria at DinoData