| Juratyrant | |
|---|---|
 | |
| Restoration illustrating known fossil remains in white | |
Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Clade: | Dinosauria |
| Clade: | Saurischia |
| Clade: | Theropoda |
| Superfamily: | †Tyrannosauroidea |
| Clade: | †Pantyrannosauria |
| Family: | †Stokesosauridae |
| Genus: | †Juratyrant Brusatte & Benson, 2013 |
| Species: | †J. langhami |
| Binomial name | |
| †Juratyrant langhami (Benson, 2008) | |
| Synonyms | |
| |
Juratyrant (meaning "Jurassic tyrant") is agenus oftyrannosauroiddinosaur from the lateJurassic period (earlyTithonian age) ofEngland. The genus contains a single species,Juratyrant langhami, which was once classified as a species ofStokesosaurus.
The species is known from a single specimen consisting of an "associated partial skeleton represented by a complete pelvis" as well as a partially complete leg and neck, back and tail vertebrae.[1] This skeleton was discovered in 1984 in Dorset. The specimen was mentioned in several papers, but was not formally described until 2008. The species was named in honor of commercial fossil collector[2] Peter Langham, who uncovered the specimen. The specimen was discovered in strata of theKimmeridge Clay dating from theTithonian, the final stage of theLate Jurassic, and belonging to thePectinatites pectinatus ammonite zone, indicating the fossil is between 149.3 and 149 million years old.[1][3]
In 2013, Zanno and Makovicky estimated thatJuratyrant weighed up to 648 kilograms (1,429 lb).[4] In 2016, Paul listed it at five metres (16 ft) and 300 kilograms (660 lb).[5]
The holotype ofJuratyrant is a partial skeleton composed of specimensOUMNH J.3311-1 throughOUMNH J.3311-30. Its components include a cervical vertebra, five dorsal vertebrae, a completesacrum, five caudal vertebrae, a completepelvic girdle, bothfemurs, bothtibiae, and various other fragments. Although initially considered a species ofStokesosaurus due to various traits of theilium, subsequent review has shown that due to the limited amount of pelvic material for basal tyrannosauroids, these traits cannot be assumed to only be present in these two species and thusS. langhami must be placed in its own genera. Once separated fromStokesosaurus,Juratyrant can be characterized by fourautapomorphies, as well as two assumed autapomorphies (which are difficult to assess due to preservation):[6]
The species was originally assigned to the genusStokesosaurus, asStokesosaurus langhami, by Roger Benson in 2008. However, later studies showed that it was not necessarily a close relative ofStokesosaurus clevelandi, thetype species of that genus. It was formally re-classified in its own genus,Juratyrant, by Benson andStephen L. Brusatte in 2013 and placed as a sister taxon toStokesosaurus clevelandi in a clade (also includingEotyrannus) of basal tyrannosauroids more advanced thanDilong.[6]
However, in 2013 Loewenet al. published a cladogram placingJuratyrant as a sister taxon toStokesosaurus insideProceratosauridae due to sharing withSinotyrannus a narrow preacetabular notch.[7] Many basal tyrannosauroids have incomplete or unknown ilia and this trait may be more widespread than currently known. This cladogram is shown below.
However, a 2016 analysis by Brusatte and Carr utilizing bothparsimonious andBayesian phylogeny placedStokesosaurus andJuratyrant as tyrannosauroids slightly more advanced than theProceratosauridae andDilong. In addition,Eotyrannus is recovered as a sister taxon of these genera in the parsimonious phylogeny.[8]
In their 2025 revision of the enigmatic Brazilian coelurosauriansMirischia andSantanaraptor, Delcourtet al. found the placement ofJuratyrant to be highly labile to analytical method: Using equal-weight phylogenetic analyses, it resolved as an ancestralmegaraptoran outside Megaraptoridae; if this is correct, it would be the oldest record of the Megaraptora at that time. However, implied-weight phylogenetic analyses gave a wholly different placement, largely consistent with the 2013 results of Loewenet al.. Here,Juratyrant formed a clade withMirischia,Santanaraptor andTanycolagreus; if this is correct,Stokesosaurus and perhapsSinotyrannus would also belong to this group, which in contrast to the 2013 results turns up basal withinManiraptoromorpha (and outside Tyrannosauroidea) in the 2025 study, close toProceratosauridae but not actually within them. In either case however,Santanaraptor resolves as a close relative ofJuratyrant.[9]
.jpg)
.jpg)
.png)
.jpg)
