Length: 4 meters

Family: Tyrannosauridae

Historical period: Cretaceous
Habitat: United Kingdom

Eotyrannus lengi (meaning "dawn tyrant") is a genus of tyrannosauroid theropod dinosaur hailing from the Early Cretaceous Wessex Formation beds, included in Wealden Group, located in the southwest coast of the Isle of Wight, United Kingdom. The remains (MIWG1997.550), consisting of assorted skull, axial skeleton and appendicular skeleton elements, from a juvenile or subadult, found in a plant debris clay bed, were described by Hutt et al. in early 2001.[1]

The etymology of the generic name refers to the animals classification as an early tyrannosaur or "tyrant lizard", while the specific name honors the discoverer of the fossil.


Eotyrannus has the following tyrannosauroid characters: serrated premaxillary teeth with a D cross section, proportionally elongate tibiae and metatarsals. Primitive characters for Tyrannosauroidea are the elongate neck vertebrae and the long, well-developed arms forelimbs along with the undecorated dorsal surface of the skull, unlike the more advanced tyrannosaurids. However this animal, proportionally, has one of the longest hands among non-avialan theropods known to date. This theropod would be a probable predator of such herbivorous dinosaurs as Hypsilophodon. The holotype of Eotyrannus are estimated to have measured about 4 meters (13 feet) long. However, as it is believed to have been juvenile, an adult specimen might have been somewhat larger.


The discovery of Eotyrannus corroborates the notion that early tyrannosauroids were gracile with long forelimbs and three-fingered grasping hands, although the somewhat large size of the animal either means that early evolution for this clade was carried out at a large size or Eotyrannus developed large size independently.[2] The find of this animal in Europe puts in question to the purported Asian origin for these animals along with North American Stokesosaurus and European Aviatyrannis arguing for a more complex biogeography for tyrannosauroids.[3]

Below is a cladogram by Loewen et al. in 2013 that includes most tyrannosauroid genera.[3]

An analysis has found Eotyrannus to be a megaraptoran closely related to taxon like Megaraptor (Profiri et al., 2014)[4]

Other Wikis[]


In popular culture[]

  • At the end of the 2013 Film Walking with Dinosaurs: The 3D Movie An illustration of Eotyrannus by Luis V. Rey were seen in the credits at the end of the movie. Along with a Dilong & a Gorgosaurus.
  • Eotyrannus was seen in Dinosaur Train as a picture illustration on the episode "Buddy Explores the Tyrannosaurs".
  • Eotyrannus was briefly seen on the 2022 PBS NOVA episode Alaskan dinosaurs as a Database creature when comparing 6 other Tyrannosaurs.




  1. Hutt, S., Naish, D., Martill, D.M., Barker, M.J., and Newbery, P. (2001). "A preliminary account of a new tyrannosauroid theropod from the Wessex Formation (Cretaceous) of southern England." Cretaceous Research, 22: 227–242.
  2. Holtz, T. R. Jr. (1994). "The phylogenetic position of the Tyrannosauridae: implications for theropod systematics." Journal of Paleontology, 68: 1100–1117.
  3. 3.0 3.1 (2013) "Tyrant Dinosaur Evolution Tracks the Rise and Fall of Late Cretaceous Oceans". PLoS ONE 8 (11): e79420. DOI:10.1371/journal.pone.0079420. 
  4. Juan D. Porfiri, Fernando E. Novas, Jorge O. Calvo, Federico L. Agnolín, Martín D. Ezcurra and Ignacio A. Cerda (2014). "Juvenile specimen of Megaraptor (Dinosauria, Theropoda) sheds light about tyrannosauroid radiation". Cretaceous Research 51: 35–55. DOI:10.1016/j.cretres.2014.04.007.