''Tyrannomimus'' (meaning "tyrant mimic") is an extinct genus of ornithomimosaurian

theropod Theropoda (; from ancient Greek , (''therion'') "wild beast"; , (''pous, podos'') "foot"">wiktionary:ποδός"> (''pous, podos'') "foot" is one of the three major groups (clades) of dinosaurs, alongside Ornithischia and Sauropodom ...

dinosaurs from the

Kitadani Formation The Kitadani Formation ( ''Kitadani-sō'') is a unit of Lower Cretaceous sedimentary rock which crops out near the city of Katsuyama in Fukui Prefecture, Japan, and it is the primary source of Cretaceous-aged non-marine vertebrate fossils in Jap ...

of Japan. The type species is ''Tyrannomimus fukuiensis''.

Discovery and naming

''Tyrannomimus'' is based on the holotype FPDM-V-11311, a partial postrcranial skeleton. Multiple referred specimens are also known. They were named as a new genus and species of ornithomimosaur in 2023. The generic name, "''Tyrannomimus''", is a reference to its morphological similarities with

tyrannosauroid Tyrannosauroidea (meaning 'tyrant lizard forms') is a superfamily (or clade) of coelurosaurian theropod dinosaurs that includes the family Tyrannosauridae as well as more basal relatives. Tyrannosauroids lived on the Laurasian supercontinen ...

s, particularly the vertical ridge of the ilium previously believed to be a synapomorphy of that clade and shared with ''

Aviatyrannis ''Aviatyrannis'' is a genus of coelurosaurian theropod dinosaur, either a tyrannosauroid or an ornithomimosaurian, from the Oxfordian-Tithonian stages of the Late Jurassic found in Portugal. Discovery and naming In 2000 Oliver Walter Misc ...

''. The specific name, "''fukuiensis''", refers to

Fukui Prefecture is a Prefectures of Japan, prefecture of Japan located in the Chūbu region of Honshū. Fukui Prefecture has a population of 737,229 (1 January 2025) and has a geographic area of 4,190 Square kilometre, km2 (1,617 sq mi). Fukui Prefecture border ...

where the fossils were found.

Classification

''Tyrannomimus'' was entered in a phylogenetic analysis by Hattori ''et al.'' (2023) and placed within the family

Deinocheiridae Deinocheiridae is an extinct family of ornithomimosaurian dinosaurs, living in Asia and North America from the Aptian until the Maastrichtian, with a possible Late Jurassic record in Europe. The family was originally named by Halszka Osmólska an ...

, as the sister taxon to ''

Harpymimus ''Harpymimus'' is a basal ornithomimosaurian theropod dinosaur from the Early Cretaceous Period (geology), Period of what is now Mongolia. Unlike later, more derived ornithomimosaurs, ''Harpymimus'' still possessed teeth, although they appear to ...

''. Their cladogram is shown below: Although it wasn't included in the dataset, Hattori ''et al.'' also consider ''

'' to be a basal ornithomimosaur due to its similarities with ''Tyrannomimus''.

Paleoenvironment

''Tyrannomimus'' lived alongside a diverse assemblage of animals, most of which are named after Fukui Prefecture. These include the sauropod ''

Fukuititan ''Fukuititan'' (meaning "giant from Fukui prefecture") is a genus of Sauropoda, sauropod dinosaur that lived during the Early Cretaceous (either Barremian or Aptian age) in the Kitadani Formation in what is now Japan. The genus contains a single s ...

'', the ornithopods '' Fukuisaurus'' and '' Koshisaurus'', and the theropods ''

Fukuiraptor ''Fukuiraptor'' ("thief of Fukui") is a genus of medium-sized megaraptoran theropod dinosaur of the Early Cretaceous epoch (either Barremian or Aptian) that lived in what is now Japan. ''Fukuiraptor'' is known from the Kitadani Formation and ...

'', ''

Fukuivenator ''Fukuivenator'' ("hunter of Fukui Prefecture") is an extinct genus of maniraptoran theropod dinosaur from the Early Cretaceous of Japan. Discovery and naming The type species ''Fukuivenator paradoxus'' was named and described in 2016 by Yoi ...

'', and ''

Fukuipteryx ''Fukuipteryx'' is an extinct genus of basal avialan dinosaurs found in Early Cretaceous deposits from Japan's Kitadani Formation. It contains one species, ''Fukuipteryx prima''.Imai, T., Azuma, Y., Kawabe, S., Shibata, M., Miyata, K., Wang, M., ...

''., Imai, T., Azuma, Y., Kawabe, S., Shibata, M., Miyata, K., Wang, M., & Zhou, Z. (2019)
An unusual bird (Theropoda, Avialae) from the Early Cretaceous of Japan suggests complex evolutionary history of basal birds
Communications Biology, 2(1). doi: 10.1038/s42003-019-0639-4

References

{{Taxonbar, from=Q122323203 Ornithomimosauria Dinosaur genera Aptian dinosaurs Fossil taxa described in 2023 Dinosaurs of Japan