Proceratosaurus

File:Proceratosaurus skull.jpg of the holotype skull and close ups of its teeth and hyoid bone, from the original 1910 description]]

In 1910, the palaeontologist Arthur Smith Woodward reported a partial skull of a theropod dinosaur, discovered some time prior by F. Lewis Bradley during excavation for a reservoir at Minchinhampton, a town in the Cotswolds in Gloucestershire, central England. Bradley had prepared the skull so that the left side was exposed, and submitted it to the Geological Society of London. Woodward made the skull the holotype specimen of a new species of the genus Megalosaurus, naming it M. bradleyi in honour of its discoverer. Also from England, Megalosaurus (the first named non-bird dinosaur, described in 1824) was historically used for any fragmentary remains of large theropods from around the world which probably did not belong in the genus.{{cite book |last=Norman |first=D.B.|author-link=David B. Norman|year=1985|title=The Illustrated Encyclopedia of Dinosaurs: An Original and Compelling Insight into Life in the Dinosaur Kingdom|publisher=Crescent Books |location=New York |pages=66 |isbn=978-0-517-46890-6 }}

At the time it was discovered, M. bradleyi was one of the most complete theropod skulls known from Europe, possibly with the exception of the crushed and hard to interpret skulls of Compsognathus and Archaeopteryx. Since 1942, the skull has been housed at the Natural History Museum, where it is catalogued as specimen NHMUK PV R 4860. The upper part of the skull is missing due to a fissure that had eroded the rock, and was partially filled with calcite. While overall well preserved, the skull is somewhat compressed from side-to side compared to what it would have been in life.{{cite news|url=http://news.bbc.co.uk/2/hi/science/nature/8340922.stm|title= Oldest T. rex relative identified|date=2009-11-04|publisher=BBC News|access-date=2009-11-04}}

In 1923, the palaeontologist Friedrich von Huene moved the species to the new genus Proceratosaurus, assuming it was the ancestor of the North American genus Ceratosaurus, but since the name was only used in a schematic, the name has been considered a nomen nudum, an invalidly published name. He validated the name three years later in two 1926 articles by providing a diagnosis (pointing out distinguishing features) of the genus. While remaining one of the best preserved theropod skulls in Europe, and globally one of the best preserved Middle Jurassic theropod skulls, it since received little scientific attention, mainly being mentioned in studies about general aspects of theropod anatomy and evolution. The holotype skull was since CT scanned at the University of Texas, further mechanically prepared to reveal additional details of the skull, jaw, and teeth, and was re-described by the palaeontologist Oliver W. M. Rauhut and colleagues in 2010.{{cite journal |last1=Milner |first1=A.C. |last2=Barrett |first2=P.M.|year=2016|title=Smith Woodward's contributions on fossil tetrapods |journal=Geological Society, London, Special Publications|volume=430 |issue=1 |pages=289–309 |doi=10.1144/SP430.13|bibcode=2016GSLSP.430..289M |s2cid=131347939 }}

File:ProceratosaurusBradleyiSize.png

The only known skull of Proceratosaurus is {{Convert|26.9|cm|in|abbr=on}} long as preserved. In 2010, the total skull length was estimated to have been {{cvt|2.98|-|3.16|m|ft|abbr=on}} and the body mass estimated at {{cvt|28|-|36|kg|lbs|abbr=on}}. Other sources have given estimates of {{cvt|3|-|4|m|ft}} in length and {{cvt|50|-|100|kg|lbs|abbr=on}} in body mass.{{cite web|last=Holtz|first=T.R.Jr.|author-link=Thomas R. Holtz Jr.|year=2008|title=Supplemental Information to: Dinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages|url=http://www.geol.umd.edu/~tholtz/dinoappendix/DinoappendixSummer2008.pdf|publisher=Department of Geology, University of Maryland|access-date=2025-04-16}} Well preserved fossils of the related tyrannosauroids Yutyrannus and Dilong indicate that they were covered in relatively simple feathers in life, similar to the down feathers of modern birds.

When complete, the skull of Proceratosaurus appears to have been relatively long but not particularly deep, being more than three times longer than high. The external nares (the bony nostril opening) makes up around 20% of the skull length, being around {{Convert|7|cm|abbr=on}} long. The antorbital fenestra (the large opening in front of the eye) is roughly triangular in shape, with a maximum length of {{Convert|6.9-7.1|cm|abbr=on}}, and this fenestra is also surrounded by a large fossa (depression) extending onto the surrounding skull bones. The partially preserved orbit (eye socket) has an "inverted egg-shape" and is marginally taller than long, at maximum {{Convert|6|cm|in|abbr=on}} and around {{Convert|5.55|cm|in|abbr=on}}, respectively. The infratemporal fenestra is narrow and elongate, being around {{Convert|5.4|cm|abbr=on}} tall and kidney-shaped, and slightly constricted at its midpoint.

File:Proceratosaurus bradleyi Skull Reconstruction.png]]

The premaxilla (the frontmost bone of the upper jaw) is relatively small, forming a rounded end to the snout. The nasal bones, as well as the contacting upper back edge of the premaxillae to their front, bear the partially preserved base of a crest, which when complete, like other proceratosaurids, likely formed a large pneumatic (air-filled) crest that ran across the midline of the skull, which in life may have been covered by keratin.{{Cite book |last=Hone |first=D.W.E.|year=2016|title=The tyrannosaur chronicles: the biology of the tyrant dinosaurs|url=https://archive.org/details/tyrannosaurchron0000hone|publisher=Bloomsbury Sigma|location=London|isbn=978-1-4729-1125-4 |pages=44, 90, 124}}{{Cite journal|last1=Hone |first1=D.W.E. |last2=Naish |first2=D.|author-link2=Darren Naish|last3=Cuthill |first3=I.C. |year=2012 |title=Does mutual sexual selection explain the evolution of head crests in pterosaurs and dinosaurs?|journal=Lethaia |volume=45 |issue=2 |pages=139–156 |doi=10.1111/j.1502-3931.2011.00300.x |bibcode=2012Letha..45..139H |issn=0024-1164}} The shape of the complete crest is unknown and was previously thought similar to that of Ceratosaurus, but after the discovery of the close, crested relative Guanlong, that genus has since been considered a likely model.

The mandible of Proceratosaurus is {{Convert|26|cm|abbr=on}} long, somewhat shorter than the length of the skull, which is relatively unusual among theropods. The retroarticular process of the mandible is relatively short. The dentary bone (the tooth-bearing front portion of the mandible) is rather slender, though the mandible becomes considerably wider towards the rear, which bears a large, elongate mandibular fenestra (opening). The front of the dentary bone tapers to a blunt point towards the front. While not all the teeth are preserved, the positions of the tooth-sockets show that each premaxilla had around 4 teeth, while each maxilla had around 22 teeth, with 20 teeth in each dentary. The teeth of Proceratosaurus are heterodont, showing differences in morphology in different positions in the jaw. The premaxillary teeth are relatively rounded in cross section. The maxillary teeth, like those of many other theropods, are ziphodont, being laterally (side-to-side) compressed and serrated.

The preserved left hyoid bone of Proceratosaurus is around {{Convert|12|cm|abbr=on}} long along its curved length. The central part of the shaft is relatively straight, while the posterior and front ends are flexed upwards.

File:Proceratosaurus restoration.jpg showing hypothetical complete crest-shape, similar to that of Guanlong]]

Woodward classified Proceratosaurus as a species of Megalosaurus in his 1910 description, due to both having four premaxillary teeth.{{cite journal | last1= Woodward | first1= A.S.|author-link=Arthur Smith Woodward|year=1910 | title= On a skull of Megalosaurus from the Great Oolite of Minchinhampton (Gloucestershire) | journal= Quarterly Journal of the Geological Society | volume= 66 | issue= 1–4 | pages= 111–115 | doi = 10.1144/GSL.JGS.1910.066.01-04.07 | bibcode= 1910QJGS...66..111W | s2cid= 129493139 | url= https://zenodo.org/record/2491937 }} Later study during the 1930s by von Huene suggested a closer relationship with Ceratosaurus, and he thought both dinosaurs represented members of the group Coelurosauria.{{cite journal|last=Huene|first=F.F.v.|author-link=Friedrich von Huene|year=1932|title=Die fossile Reptil-Ordnung Saurischia, ihre Entwicklung und Geschichte|journal=Monographien zur Geologie und Palaeontologie (Serie 1)|volume=4|pages=1–361}}

It was not until the late 1980s, after Ceratosaurus had been shown to be a much more basal theropod and not a coelurosaur, that the classification of Proceratosaurus was again re-examined. The palaeontologist Gregory S. Paul suggested that it was a close relative of Ornitholestes, again mainly due to the crest on the nose (though the idea that Ornitholestes bore a nasal crest was later disproved).{{cite book|last1=Carpenter|first1=K.|author-link=Kenneth Carpenter|last2=Miles|first2=C.|last3=Ostrom|first3=J.H.|author-link3=John Ostrom|last4=Cloward|first4=K.|year=2005|chapter=Redescription of the Small Maniraptoran Theropods Ornitholestes and Coelurus|pages=49–71|editor-last=Carpenter|editor-first=K.|title=The Carnivorous Dinosaurs |series=Life of the Past |publisher=Indiana University Press|isbn=978-0-253-34539-4}} Paul considered both Proceratosaurus and Ornitholestes to be neither ceratosaurs nor coelurosaurs, but instead primitive allosauroids. Furthermore, Paul considered the much larger theropod species Piveteausaurus divesensis to belong to the genus Proceratosaurus, coining the new combination Proceratosaurus divesensis.{{cite book |last=Paul |first=G.S. |author-link=Gregory S. Paul|year=1988 |title=Predatory Dinosaurs of the World |location=New York |publisher=Simon and Schuster |pages=366–369|url=https://archive.org/details/predatorydinosau00paul/page/366 |isbn=978-0-671-61946-6}} However, no overlapping bones between the two had yet been exposed from the rock around their fossils, and future study showed that they were indeed distinct.

A 1998 phylogenetic analysis by Thomas R. Holtz Jr. found Proceratosaurus to be a basal coelurosaur.{{cite journal|last=Holtz|first=Thomas|author-link=Thomas R. Holtz Jr.|year=1998|title=A new phylogeny of the carnivorous dinosaurs |journal=Gaia|volume=15|pages=5–61|url=http://www.mnhn.ul.pt/geologia/gaia/1.pdf}} Several subsequent studies confirmed this, finding Proceratosaurus and Ornitholestes only distantly related to the ceratosaurids and allosauroids, though one opinion published in 2000 considered Proceratosaurus a ceratosaurid without presenting supporting evidence. A 2004 study by Holtz also placed Proceratosaurus among the coelurosaurs, though with only weak support, and again found an (also weakly supported) close relationship with Ornitholestes.{{Cite journal|last1 = Rauhut|first1 = O.W.M.| last2=Milner| first2=A.C.| last3=Moore-Fay| first3=S.|year=2010|title = Cranial osteology and phylogenetic position of the theropod dinosaur Proceratosaurus bradleyi(Woodward, 1910) from the Middle Jurassic of England| journal=Zoological Journal of the Linnean Society| volume=158| pages=155–195| doi=10.1111/j.1096-3642.2009.00591.x|doi-access=free}}

The first major re-evaluation of Proceratosaurus and its relationships was published in 2010 by Oliver Rauhut and colleagues. Their study concluded that Proceratosaurus was in fact a coelurosaur, and moreover a tyrannosauroid, a member of the lineage leading to the giant tyrannosaurs of the Late Cretaceous. Furthermore, they found that Proceratosaurus was most closely related to the tyrannosauroid Guanlong from China. They named the clade containing these two dinosaurs Proceratosauridae, defined as all theropods closer to Proceratosaurus than to Tyrannosaurus, Allosaurus, Compsognathus, Coelurus, Ornithomimus, or Deinonychus.

File:Proceratosaurus holotype.JPG

File:Guanlong fossil.jpg

File:Proceratosaurus bradleyi reconstructed skeleton.png]]

Subsequent published analyses have consistently recovered Proceratosaurus in a close relationship with Guanlong, as well as the genera Kileskus and Sinotyrannus. Other genera which may be close relatives include Yutyrannus, Dilong, and Stokesosaurus, but the exact affinities of these taxa as they relate to Proceratosaurus remain uncertain.{{Cite journal | last1 = Loewen | first1 = M.A. |last2 = Irmis | first2 = R.B.| last3 = Sertich | first3 = J.J.W. | last4 = Currie | first4 = P.J.|author-link4=Philip J. Currie | last5 = Sampson | first5 = S.D. | year = 2013| title = Tyrant Dinosaur Evolution Tracks the Rise and Fall of Late Cretaceous Oceans| journal = PLoS ONE | volume = 8 | issue = 11 | pages = e79420 | doi = 10.1371/journal.pone.0079420 | pmid = 24223179| pmc = 3819173| bibcode = 2013PLoSO...879420L| doi-access = free }}{{cite journal |last1=Delcourt |first1=R.|last2=Grillo |first2=O.N.|year=2018|title=Tyrannosauroids from the Southern Hemisphere: Implications for biogeography, evolution, and taxonomy|journal=Palaeogeography, Palaeoclimatology, Palaeoecology |volume=511 |pages=379–387|doi=10.1016/j.palaeo.2018.09.003 |bibcode=2018PPP...511..379D |s2cid=133830150 }} Below is a cladogram from a 2022 study by Darren Naish and Andrea Cau on the genus Eotyrannus, which recovered similar relationships to previous studies.{{cite journal |last1= Naish |first1= D.|author-link=Darren Naish |last2= Cau |first2= A. |year=2022 |title= The osteology and affinities of Eotyrannus lengi, a tyrannosauroid theropod from the Wealden Supergroup of southern England |journal= PeerJ |volume= 10 |pages= e12727 |doi= 10.7717/peerj.12727|pmid= 35821895 |pmc= 9271276 |doi-access= free }}

{{clade| style=font-size:95%; line-height:95%

|label1=Tyrannosauroidea

|1={{clade

|1={{clade

|1=Juratyrant

|2=Stokesosaurus 80px }}

|2={{clade

|1=Coeluridae

|2={{clade

|label1=Proceratosauridae

|1={{clade

|1=Dilong

|2={{clade

|1=Guanlong 70px

|2={{clade

|1=Proceratosaurus

|2=Sinotyrannus 100px }} }} }}

|label2=Pantyrannosauria

|2={{clade

|1=Yutyrannus 100px

|2={{clade

|1=Eotyrannus

|2={{clade

|1=Xiongguanlong

|2={{clade

|1=Megaraptora

|2=Eutyrannosauria

File:Proceratosaurus NT.jpg

The study of the general biology of Proceratosaurus is somewhat limited by the lack of any post-cranial remains. However, the more well-understood anatomy of the related Guanlong allows for general inferences about the biology of Proceratosauridae as a whole. Proceratosaurids were small-bodied animals, in sharp contrast to the tyrannosauroids of the Late Cretaceous. In spite of this, they possessed many of the key adaptations which would come to define the large tyrannosaurids of later periods. In particular, proceratosaurids already possessed the fused nasal bones that were inherited by their successors. In later forms, the fusion of the dual nasal bones is believed to have been an adaptation to allow the skull to withstand higher bite forces. Proceratosaurus also possessed the characteristic "D-shaped" premaxillary teeth that are unique to tyrannosauroids. According to Rauhut and colleagues in 2010, this suite of adaptations indicates that the "puncture-pull" feeding strategy of derived tyrannosaurids was already present in proceratosaurids.

A 2023 study by the palaeontologist Evan Johnson-Ransom and colleagues used data from the skulls of Proceratosaurus and Guanlong to create a composite model of a hypothetical, complete proceratosaurid skull. They added virtual muscles to these model skulls and used them to estimate the highest possible bite force. Their model for Proceratosaurus exhibited an estimated bite force of {{convert|390|N|lbf|abbr=off}}, comparable to Dilong or a juvenile Tarbosaurus. These results confirmed the hypothesis that proceratosaurids and other early-diverging tyrannosauroids had a proportionately lower ability to withstand stresses than their derived tyrannosaurid cousins. This is believed to have implications for the dietary ecology and behaviour of proceratosaurids. This lower proportional force distribution would have precluded proceratosaurids from attacking large prey, and therefore they most likely fed on small-bodied prey such as small ornithischians and primitive mammals.{{cite journal |last1=Johnson-Ransom |first1=E.|last2=Li |first2=F.|last3=Xu |first3=X.|author-link3=Xu Xing|last4=Ramos |first4=R.|last5=Midzuk |first5=A.J. |last6=Thon |first6=U.|last7=Atkins-Weltman |first7=K.|last8=Snively |first8=E.|year=2024|title=Comparative cranial biomechanics reveal that Late Cretaceous tyrannosaurids exerted relatively greater bite force than in early-diverging tyrannosauroids|journal=The Anatomical Record |volume=307 |issue=5 |pages=1897–1917 |doi=10.1002/ar.25326 |pmid=37772730 }}

Proceratosaurus and its relatives also possessed highly pneumatised skull bones. Cranial sinus tissue excavated the maxillae, jugals, and lacrimal bones, and the jugals themselves were very rugose, which suggests that the area was heavily irrigated by blood vessels. The jugal bone is generally not part of the cranial musculature of most dinosaurs, and the palaeontologist Xu Xing suggested in 2016 that they may have been an important display area for many groups of dinosaur, including proceratosaurids.{{cite journal|last1=Sullivan |first1=C.|last2=Xu |first2=X.|author-link2=Xu Xing|year=2016|title=Morphological Diversity and Evolution of the Jugal in Dinosaurs |journal=The Anatomical Record |volume=300 |issue=1 |pages=30–48|doi=10.1002/ar.23488 |pmid=28000403 }} According to Rauhut and colleagues, the prominent head crest of Proceratosaurus was also likely to have been used as a display feature. Paul agreed in 2016 and pointed out that the crest would have been too delicate for head-butting.{{Cite book|last=Paul|first=G.S.|author-link=Gregory S. Paul|year=2016|title=The Princeton Field Guide to Dinosaurs|volume=2|publisher=Princeton University Press|isbn=978-1-78684-190-2|oclc=985402380|pages=105|url=http://worldcat.org/oclc/985402380}}

File:Bajocian_Europe_map.png period, which had a broadly similar paleogeography to the Bathonian in which Proceratosaurus lived. The London-Brabant Massif is labelled "LBM", while CNSD stands for "Central North Sea Dome"]]

The only known Proceratosaurus specimen was found in the Great Oolite Group in strata dating to the Late Bathonian age of the Middle Jurassic. During the Middle Jurassic, Britain was located in the subtropics,{{Cite journal |last=van Konijnenburg-van Cittert |first=J.H.A. |year=2008 |title=The Jurassic fossil plant record of the UK area |url=https://linkinghub.elsevier.com/retrieve/pii/S0016787808802581 |journal=Proceedings of the Geologists' Association |volume=119 |issue=1 |pages=59–72 |doi=10.1016/S0016-7878(08)80258-1|bibcode=2008PrGA..119...59V }} and along with the rest of Western Europe formed a part of an island archipelago, in a seaway narrowly separated from Laurentia (landmass consisting of North America and Greenland) to the west and the Fennoscandian Shield to the northeast. Britain was divided into a number of islands separated by shallow seas,{{cite journal|last1=Buffetaut|first1=E.|last2=Gibout|first2=B.|last3=Launois|first3=I.|last4=Delacroix|first4=C.|year=2011|title=The sauropod dinosaur Cetiosaurus Owen in the Bathonian (Middle Jurassic) of the Ardennes (NE France): insular, but not dwarf|url=|journal=Carnets de Géologie|volume=06|pages=149–161}} including one formed by the London–Brabant Massif to the east, the Welsh Massif to the west, the Cornubian Massif to the southwest, and the Pennine-Scottish Massif to the north. The coastlines of these islands fluctuated throughout the period, with areas of shallow marine deposition being sometimes transformed temporarily into lagoonal or terrestrial environments with lakes and ponds, and it is suggested that animals were freely able to disperse between them, as well as possibly with the Fennoscandian Shield. The exact locality where Proceratosaurus was discovered has been suggested to correspond to the rocks of the White Limestone Formation,{{cite web |last=Carrano |first=M.|year=2004 |title=Minchinhampton reservoir (BMNH R4860) (Jurassic of the United Kingdom) |url=https://paleobiodb.org/classic/basicCollectionSearch?collection_no=45883&is_real_user=1 |website=The Paleobiology Database}} although some authors have suggested this locality is part of the overlying Forest Marble Formation.{{cite book|last1=Weishampel|first1=D.B.|last2=Barrett|first2=P.M.|last3=Coria|first3=R.A.|last4=Le Loeuff|first4=J.|last5=Xu|first5=X.|last6=Zhao|first6=X.|last7=Sahni|first7=A.|last8=Gomani|first8=E.M.P.|last9=Noto|first9=C.R.|year=2004|chapter=Dinosaur Distribution|editor-last=Weishampel|editor-first=D.B.|editor2-last=Dodson|editor2-first=P.|editor3-last=Osmólska|editor3-first=H.|title=The Dinosauria|edition=2nd|pages=517–606|publisher=University of California Press |isbn=0-520-24209-2}}

The flora from the Bathonian aged Taynton Limestone Formation in Oxfordshire to the east was dominated by araucarian and cheirolepidiacean conifers, the probable conifer Pelourdea, as well as bennettitaleans, with other plants including cycads (Ctenis), ferns (Phlebopteris, Coniopteris), Caytoniales, the living genus Ginkgo, and the seed ferns Pachypteris and Komlopteris, representing a probably seasonally dry coastal environment.{{Cite journal |last1=Cleal |first1=C.J. |last2=Rees |first2=P.M. |year=2003 |title=The Middle Jurassic flora from Stonesfield, Oxfordshire, UK |journal=Palaeontology |volume=46 |issue=4 |pages=739–801 |bibcode=2003Palgy..46..739C |doi=10.1111/1475-4983.00319 |issn=0031-0239 |s2cid=129569932 |doi-access=free}} The existence of a seasonally-arid climate during the Bathonian period in Britain is corroborated by geological evidence of natural fires among the fossilised vegetation of the White Limestone Formation, which implies the periodic occurrence of long drought episodes.{{Cite journal |last1=Wills |first1=S.|last2=Bernard |first2=E.L.|last3=Brewer |first3=P.|last4=Underwood |first4=C.J. |last5=Ward |first5=D.J. |year=2019 |title=Palaeontology, stratigraphy and sedimentology of Woodeaton Quarry (Oxfordshire) and a new microvertebrate site from the White Limestone Formation (Bathonian, Jurassic) |url=https://linkinghub.elsevier.com/retrieve/pii/S0016787819300197 |journal=Proceedings of the Geologists' Association |language=en |volume=130 |issue=2 |pages=170–186 |bibcode=2019PrGA..130..170W |doi=10.1016/j.pgeola.2019.02.003 |s2cid=135409990}} The manner of deposition was primarily by slow-moving bodies of water in a coastal or near-coastal alluvial or lagoonal setting, which was periodically interrupted by high-energy events like floods, which are reflected in the geological record of several localities.{{cite journal |last1=Barron |first1=J.M. |last2=Lott |first2=G.K. |last3=Riding |first3=J.B. |year=2012 |title=Stratigraphical framework for the Middle Jurassic strata of Great Britain and the adjoining continental shelf |url=https://www.researchgate.net/publication/265611781_Stratigraphical_framework_for_the_Middle_Jurassic_strata_of_Great_Britain_and_the_adjoining_continental_shelf |journal=British Geological Survey Research Report |volume=11 |issue=06 |pages=1-9 |isbn=9780852726952}}

File:Megalosaurus dinosaur.png, a large theropod also from the Great Oolite Group of England, which Proceratosaurus was once thought to be congeneric with]]

A diverse marine assemblage is known from the Great Oolite Group, including invertebrates, such as bivalves, brachiopods, and echinoderms, as well as vertebrates such as sharks, chimaeras, and ray-finned fish. Large terrestrial vertebrate remains have also been found in the Great Oolite Group. Other British dinosaurs known from the Bathonian period in Britain include the large theropod Megalosaurus{{Cite journal |last=Benson |first=R.B.J. |year=2010 |title=A description of Megalosaurus bucklandii (Dinosauria: Theropoda) from the Bathonian of the UK and the relationships of Middle Jurassic theropods |journal=Zoological Journal of the Linnean Society |language=en |volume=158 |issue=4 |pages=882–935 |doi=10.1111/j.1096-3642.2009.00569.x |doi-access=free}} and the sauropod Cetiosaurus.{{Cite journal |last1=Upchurch |first1=P.|last2=Martin |first2=J.|year=2003|title=The anatomy and taxonomy of Cetiosaurus (Saurischia, Sauropoda) from the Middle Jurassic of England|journal=Journal of Vertebrate Paleontology |language=en |volume=23 |issue=1 |pages=208–231 |doi=10.1671/0272-4634(2003)23[208:TAATOC]2.0.CO;2 |issn=0272-4634 |s2cid=55360032}} Ornithischian remains have also been discovered, but none of these remains have been given scientific names. Bones and teeth of stegosaurs, as well as teeth of ankylosaurs, basal thyreophorans, and heterodontosaurids have been found, alongside remains that have not been confidently assigned to a single group.{{Cite journal |last1=Wills |first1=S.|last2=Underwood |first2=C.J. |last3=Barrett |first3=P.M. |year=2023 |title=A hidden diversity of ornithischian dinosaurs: U.K. Middle Jurassic microvertebrate faunas shed light on a poorly represented period|journal=Journal of Vertebrate Paleontology |volume=43 |issue=5 |doi=10.1080/02724634.2024.2323646 |issn=0272-4634}} Maniraptoran theropods, possibly including dromaeosaurs, were also present in the environment, also only known from indeterminate teeth.{{Cite journal |last1=Wills |first1=S.|last2=Underwood |first2=C.J. |last3=Barrett |first3=P.M. |year=2023 |title=Machine learning confirms new records of maniraptoran theropods in Middle Jurassic UK microvertebrate faunas |journal=Papers in Palaeontology |language=en |volume=9 |issue=2 |pages=e1487 |bibcode=2023PPal....9E1487W |doi=10.1002/spp2.1487 |issn=2056-2799 |doi-access=free}} Pterosaurs from the Great Oolite Group included rhamphorhynchids such as the genus Klobiodon, as well as indeterminate probable monofenestratans.{{cite journal|last1=O’Sullivan|first1=M.|last2=Martill|first2=D.M.|year=2018|title=Pterosauria of the Great Oolite Group (Bathonian, Middle Jurassic) of Oxfordshire and Gloucestershire, England|journal=Acta Palaeontologica Polonica|volume=63|issue=X|pages=xxx–xxx|url=http://www.app.pan.pl/archive/published/app63/app004902018.pdf}} Large rhamphorhynchoids like Dearc and monofenestratans like Ceoptera are also known from other Bathonian aged localities in the British Isles.{{Cite journal |last1=Martin-Silverstone |first1=E.|last2=Unwin |first2=D.M. |last3=Cuff |first3=A.R. |last4=Brown |first4=E.E. |last5=Allington-Jones |first5=L.|last6=Barrett |first6=P.M. |year=2024|title=A new pterosaur from the Middle Jurassic of Skye, Scotland and the early diversification of flying reptile |journal=Journal of Vertebrate Paleontology |language=en |doi=10.1080/02724634.2023.2298741 |issn=0272-4634 |doi-access=free}} Crocodyliformes were also present in the environment, including atoposaurids and goniopholids.{{Cite journal |last=Panciroli|first=E.|last2=Benson|first2=R.B.J. |last3=Walsh|first3=S.|last4=Butler|first4=R.J. |last5=Castro|first5=T.A.|last6=Jones|first6=M.E.H. |last7=Evans|first7=S.E. |year=2020|title=Diverse vertebrate assemblage of the Kilmaluag Formation (Bathonian, Middle Jurassic) of Skye, Scotland |url=https://discovery.ucl.ac.uk/id/eprint/10108804/1/PANCIROLIetal_TRE-2020-0004.R1_Proof_hi.pdf |journal=Earth and Environmental Science Transactions of the Royal Society of Edinburgh |volume=111 |issue=3 |pages=135–156 |doi=10.1017/s1755691020000055 |issn=1755-6910}}

The Great Oolite Group is also host to one of the most diverse assemblages of primitive mammal fossils of the entire Jurassic Period. This locality, the Kirtlington Mammal Bed, preserves remains from large animals as well, but the majority of fossils known are from mammals and their close relatives. Tritylodontid cynodonts, morganucodonts, docodonts, allotherians, haramiyidans, shuotheriids, eutriconodonts, and early-diverging cladotherians are known from the Kirtlington Bed.{{cite web |last= |first= |date= |title=Kirtlington 3p (Mammal Bed) |url=https://www.mindat.org/paleo_collection.php?col=39075 |access-date=28 August 2018 |work=Paleobiology Database |publisher= |quote=}} Remains of salamanders, frogs, albanerpetontids, turtles, lizards, choristoderes, and sphenodontians have also been discovered in the Kirtilngton mammal bed. Analogous assemblages of vertebrate microfossils have also been found at other localities of similar age, including the Kilmaluag Formation on the Isle of Skye, Scotland, considerably further to the north, whose microvertebrate assemblage shares numerous species with the Kirtlington Fauna, though more completely preserved.

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• [https://sketchfab.com/3d-models/proceratosaurus-skull-a0439952021a47dc827e31daed8cfac7 3D scan of the holotype skull on Sketchfab]

{{Theropoda|C.}}

{{Taxonbar|from=Q132619}}

Category:Proceratosauridae

Category:Bathonian dinosaurs

Category:Middle Jurassic dinosaurs of Europe

Category:Jurassic England

Category:Fossils of England

Category:Fossil taxa described in 1926

Category:Taxa named by Friedrich von Huene