Proceratosaurus

In 1910, the British 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 in the vicinity of Minchinhampton, a town in South West 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 (the original type specimen with which a species is defined) of a new species of the genus Megalosaurus, naming it M. bradleyi in honour of its discoverer.{{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 |url=https://web.archive.org/web/20170729150848/https://academic.oup.com/zoolinnean/article-lookup/doi/10.1111/j.1096-3642.2009.00591.x |journal=Zoological Journal of the Linnean Society |volume=158 |pages=155–195 |doi=10.1111/j.1096-3642.2009.00591.x |doi-access=}} Megalosaurus, the first named non-bird dinosaur, described in 1824 also based on English fossils, was historically used for any fragmentary remains of large theropods from around the world (wastebasket taxon).{{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 }}

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

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 in London, 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 a 1923 publication, the German palaeontologist Friedrich von Huene placed the species in the newly coined genus Proceratosaurus, assuming it was an early member of the Ceratosaurus lineage.Huene, F.v. (1923). Carnivorous Saurischia in Europe since the Triassic. Bulletin of the Geological Society of America 34: 449–458. The name derives from the Greek {{lang|grc|pro}} {{gloss|before}} and the genus name Ceratosaurus.{{cite web |last=Creisler |first=B. |date=July 7, 2003 |title=Dinosauria translation and pronunciation guide P |url=http://www.dinosauria.com/dml/names/dinoh.htm |url-status=dead |archive-url=https://web.archive.org/web/20100818013919/http://www.dinosauria.com/dml/names/dinop.htm |archive-date=August 18, 2010 |access-date=April 28, 2025 |website=Dinosauria On-Line}} However, the name was invalidly published as it was only used in a diagram in the paper and not mentioned at all in the main text. Von Huene validated the name three years later in two 1926 articles, which contained the required technical description/diagnosis in order for the name to be considered valid. Von Huene considered the crest, as well as the shape of the maxilla (the main tooth bearing upper jaw bone), squamosal (a bone towards the back of the skull), the {{Dinogloss|external nares}} (bony nostril openings) and the {{Dinogloss|infratemporal fenestra}} (the skull opening behind the orbit/eye socket) as distinctive.{{Cite journal |last=Huene |first=F.v. |author-link=Friedrich von Huene |date=1926 |title=On several known and unknown reptiles of the order Saurischia from England and France |url=https://www.tandfonline.com/doi/abs/10.1080/00222932608633437 |journal=Annals and Magazine of Natural History |language=en |volume=17 |issue=101 |pages=473–489 |doi=10.1080/00222932608633437 |issn=0374-5481|url-access=subscription }}{{cite journal|last1=Huene |first1=F.v. |author-link=Friedrich von Huene| year=1926| url=https://publicaciones.fcnym.unlp.edu.ar/rmlp/article/view/1393 | title=The carnivorous Saurischia in the Jura and Cretaceous Formations, principally in Europe | journal=Revista del Museo de La Plata |volume=29 |pages=69–70}} Huene regarded the crest, which he thought to represent the base of a nasal horn, as a feature supporting its relationship with Ceratosaurus.{{Cite journal |last1=Carrano |first1=M.T. |last2=Sampson |first2=S.D. |year=2008 |title=The phylogeny of Ceratosauria (Dinosauria: Theropoda) |url=https://www.tandfonline.com/doi/full/10.1017/S1477201907002246 |journal=Journal of Systematic Palaeontology |language=en |volume=6 |issue=2 |pages=183–236 |doi=10.1017/S1477201907002246 |bibcode=2008JSPal...6..183C |issn=1477-2019}}

While remaining one of the best preserved theropod skulls in Europe, and globally one of the best preserved Middle Jurassic theropod skulls, it subsequently received little scientific attention, mainly being mentioned in studies about general aspects of theropod anatomy and evolution. The skull was re-described by the German palaeontologist Oliver Rauhut and colleagues in 2010, undergoing further mechanical preparation to reveal additional details of the skull, jaw, and teeth, as well as being CT scanned at the University of Texas during the same year as part of this project.{{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 }}

In 1988, American paleontologist Gregory S. Paul considered the much larger theropod species Piveteausaurus divesensis from the Middle-Late Jurassic of France to belong to Proceratosaurus, coining the new combination Proceratosaurus divesensis.{{cite book |last=Paul |first=G.S. |author-link=Gregory S. Paul |url=https://archive.org/details/predatorydinosau00paul/page/366 |title=Predatory Dinosaurs of the World |publisher=Simon and Schuster |year=1988 |isbn=978-0-671-61946-6 |location=New York |pages=366–369}} However, later researchers, including Rahut and colleagues in their 2010 redescription, rejected this suggestion, finding the two species to be unrelated.{{Cite journal |last=Carrano |first=M.T. |last2=Benson |first2=R.B.J. |last3=Sampson |first3=S.D. |year=2012 |title=The phylogeny of Tetanurae (Dinosauria: Theropoda) |url=https://www.tandfonline.com/doi/full/10.1080/14772019.2011.630927 |journal=Journal of Systematic Palaeontology |language=en |volume=10 |issue=2 |pages=211–300 |doi=10.1080/14772019.2011.630927 |issn=1477-2019}}

File:ProceratosaurusBradleyiSize.png

The only known skull of Proceratosaurus is {{cvt|26.9|cm|in}} long as preserved. The 2010 redescription considered it a small to medium-sized dinosaur, and estimated a total body length of {{cvt|2.98|-|3.16|m|ft|abbr=on}} and a body mass of {{cvt|28|-|36|kg|lbs|abbr=on}}. These authors found the holotype specimen to be at least a sub-adult dinosaur, as the bone did not show features associated with juveniles. Other sources gave 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, and according to British paleontologist Dave Hone "it is reasonable to infer" that all tyrannosauroids had similar feathers.{{Multiple image

| header = Skull anatomy of proceratosaurids

| image1 = Proceratosaurus bradleyi Skull Reconstruction (alt).png

| caption1 = Diagram of the skull showing known parts in white, with missing parts of the skull reconstructed after Guanlong

| image2 = GuanlongWucaiiSkulls.png

| caption2 = Skull diagram of Guanlong including an adult specimen (IVPP V14531, left) and a juvenile (IVPP V14532, right). Preserved parts are in white, with reconstructed parts in grey

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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 {{Dinogloss|external naris}} (the opening at the front of the skull from which the nostril originates), makes up around 20% of the skull length, around {{cvt|7|cm}} long, relatively large compared to the size of the skull. The maximum length of the nares is inclined upwards towards the back of the skull (posterodorsally) at an angle of approximately 30 degrees, differing from that of the closely related Guanlong, where the maximum length of the nares is roughly horizontal relative to the skull length. The {{Dinogloss|antorbital fenestra}} (the large opening in front of the eye) is roughly triangular in shape, with a maximum length of {{cvt|6.9-7.1|cm}}, and as is found in other theropods, this fenestra is also surrounded by a large {{Dinogloss|fossa}} (depression) extending onto the surrounding skull bones. On the maxilla, the forward edge of the fossa extends considerably further foward (anterior) and below (ventral) the promaxillary foramen (a hole in the skull), a unique and distinctive characteristic (autapomorphy) of this species. The partially preserved {{Dinogloss|orbit}} (eye socket) has an inverted egg-shape, and was probably marginally taller than long when complete, with a maximum estimated complete height of {{cvt|6|cm|in}}, and a measured length of {{cvt|5.55|cm|in}}, respectively. The infratemporal fenestra is narrow and elongate, being around {{cvt|5.4|cm}} tall and kidney-shaped, and slightly constricted at its midpoint.

The premaxilla (the frontmost bone of the upper jaw) is relatively small, forming a rounded end to the snout. The {{Dinogloss|nasal}} bones, as well as the contacting upper back edge of the premaxillae to their front, bear the partially preserved base of a crest. The preserved part of the crest overhangs the internarial bar that forms the upper part of the bony nostril, a distinguishing feature of this genus. Like other proceratosaurids, Proceratosaurus probably had a large pneumatic (hollow) crest that ran across the midline of the skull, which may have been covered by keratin.{{Cite book |last=Hone |first=D.W.E. |url=https://archive.org/details/tyrannosaurchron0000hone |title=The Tyrannosaur Chronicles: the Biology of the Tyrant Dinosaurs |publisher=Bloomsbury Sigma |year=2016 |isbn=978-1-4729-1125-4 |location=London |pages=44, 90, 124-125}}{{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 to be 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 maxilla (the main tooth bearing bone of the upper jaw) is long, around {{cvt|16.3|cm}} in length, probably over 50% of the total complete skull length. The front portion of the maxilla forward of the antorbital fenestra differs considerably in shape from its counterpart in Guanlong. In contrast to Guanlong, the jugal bone of the skull makes little contribution to the margin/border of the antorbital fenestra in Proceratosaurus.

The mandible (lower jaw) of Proceratosaurus is {{cvt|26|cm}} long, somewhat shorter than the skull, which is unusual for theropods. The retroarticular process at the posterior end of the mandible where the lower jaw articulates with the skull is relatively short. The {{Dinogloss|dentary}} bone (the tooth-bearing front portion of the mandible) is slender, though it becomes considerably wider towards the rear, which bears a large, elongate {{Dinogloss|mandibular fenestra}} (opening), with a length of {{cvt|2.6|cm}}. The dentary bone tapers to a blunt point towards the front. Although not all teeth are preserved, the tooth sockets show that each premaxilla had around 4 teeth, each maxilla had around 22 teeth, and each dentary had around 20 teeth. The teeth are heterodont, showing differences in morphology depending on their position in the jaw. The premaxillary teeth are D-shaped in cross-section, with the front facing surface of the teeth being arched. The maxillary teeth, like those of many other theropods, are ziphodont, that is they are narrow from side-to-side and serrated. The three frontmost pairs of teeth of the lower jaw are procumbent, that is they protrude forwards. The denticles are rounded and chisel-like in shape. The density of denticles is highest in the frontmost teeth in both the upper and lower jaws. In the teeth further back, denticle density increases in the posteriormost teeth of the maxilla but remains constant in the dentary.

The preserved left {{Dinogloss|hyoid}} (bone that supported the tongue) is around {{cvt|12|cm}} 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 speculative complete crest-shape, similar to that of Guanlong]]

Woodward classified Proceratosaurus as a species of Megalosaurus in his 1910 description, because both had 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 }} This trait was later shown to be the ancestral condition found in the common ancestor of all theropod dinosaurs, and thus not a distinguishing characteristic. 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.v.|author-link=Friedrich von Huene|year=1932|title=Die fossile Reptil-Ordnung Saurischia, ihre Entwicklung und Geschichte|language=de |trans-title=The fossil reptile order Saurischia, its development and history|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 (primitive/early diverging) theropod and not a coelurosaur, that the classification of Proceratosaurus was re-examined. Paul suggested in 1988 that it was a close relative of Ornitholestes, again mainly because of 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.

A 1998 phylogenetic analysis by American paleontologist Thomas R. Holtz Jr. found Proceratosaurus to be a basal coelurosaur.{{cite journal|last=Holtz|first=T.R.Jr|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 ceratosaurids and allosauroids, though one opinion published in 2000 considered Proceratosaurus a ceratosaurid without presenting supporting evidence.{{cite journal|last1=Madsen|first1=J.H.|last2=Welles|first2=S.P.|year=2000|title=Ceratosaurus (Dinosauria, Theropoda). A revised osteology|journal=Miscellaneous Publication, Utah Geological Survey|volume=2|pages=1–80}} A 2004 study by Holtz and colleagues also placed Proceratosaurus among the coelurosaurs, though with only weak support, and again found an (also weakly supported) close relationship with Ornitholestes.{{cite book|last1=Holtz|first1=T.R.Jr|author-link=Thomas R. Holtz Jr.|last2=Molnar|first2=R.E.|last3=Currie|first3=P.J.|author-link3=Philip J. Currie|year=2004|chapter=Basal Tetanurae|editor-last=Weishampel|editor-first=D.B.|editor2-last=Dodson|editor2-first=P.|editor3-last=Osmólska|editor3-first=H.|title=The Dinosauria|edition=2nd|location=Berkeley|publisher=University of California Press|pages=71–110}}

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, an early diverging member of the lineage culminating in the large tyrannosaurids 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. Proceratosaurus is currently the oldest known tyrannosauroid, along with Kileskus, which is known from equivalently aged rocks in Western Siberia.{{Cite journal |last1=Averianov |first1=A.O.|last2=Osochnikova |first2=A.|last3=Skutschas |first3=P.|last4=Krasnolutskii |first4=S.|last5=Schellhorn |first5=R.|last6=Schultz |first6=J.A.|last7=Martin |first7=T.|year=2021 |title=New data on the tyrannosauroid dinosaur Kileskus from the Middle Jurassic of Siberia, Russia |url=https://www.tandfonline.com/doi/full/10.1080/08912963.2019.1666839 |journal=Historical Biology |language=en |volume=33 |issue=7 |pages=897–903 |doi=10.1080/08912963.2019.1666839 |bibcode=2021HBio...33..897O |issn=0891-2963}} The fossil record of early coelurosaurians and their initial diversification is sparse, and it has previously been disputed whether coelurosaurian dinosaurs had suddenly radiated at the Middle–Late Jurassic boundary, or gradually during the late Early Jurassic{{snd}}Middle Jurassic. The presence of tyrannosauroids such as Proceratosaurus in the Bathonian implies that the initial diversification of Coelurosauria had already considerably progressed by the early Middle Jurassic.

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 British paleontologist Darren Naish and Italian paleontologist 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

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|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

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|1=Eotyrannus

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|1=Xiongguanlong

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|1=Megaraptora

|2=Eutyrannosauria

}} }} }} }} }} }} }} }}

File:Proceratosaurus NT.jpg

The study of the general biology of Proceratosaurus is limited by the lack of postcranial remains. However, the better-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 tyrannosaurids of the Late Cretaceous. In spite of this, they possessed many of the key adaptations of Cretaceous tyrannosaurids. In particular, proceratosaurids already possessed the fused nasal bones that were inherited by their successors. In later forms, the fusion of the left and right nasal bones is believed to have been an adaptation for withstanding 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 tyrannosaurids was already present in proceratosaurids. In the "puncture-pull" strategy, which was likely exhibited by many coelurosaurian theropods, following closure of the jaws around prey, the head was pulled back, causing the theropod's teeth to slice through the held flesh to rip it away from the body of the prey.{{Cite journal |last1=Torices |first1=A.|last2=Wilkinson |first2=R.|last3=Arbour |first3=V.M.|author-link3=Victoria Arbour |last4=Ruiz-Omeñaca |first4=J.I.|last5=Currie |first5=P.J.|author-link5=Philip J. Currie |year=2018 |title=Puncture-and-Pull Biomechanics in the Teeth of Predatory Coelurosaurian Dinosaurs |url=https://linkinghub.elsevier.com/retrieve/pii/S0960982218303713 |journal=Current Biology |language=en |volume=28 |issue=9 |pages=1467–1474.e2 |doi=10.1016/j.cub.2018.03.042|pmid=29706515 |bibcode=2018CBio...28E1467T }}

{{multiple image

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| image2 = Stress results for the cranium of Proceratosaurus.tiff

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| footer = Left: comparison of cranial stress for Proceratosaurus (top) with other tyrannosauroids. Right: biting stresses in reconstructed skull of Proceratosaurus in various views. Following a 2023 study

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A 2023 study by the American palaeontologist Evan Johnson-Ransom and colleagues used data from the skulls of Proceratosaurus and Guanlong to create a virtual composite model of a hypothetical, complete Proceratosaurus skull, and created other virtual skull models for other tyrannosauroids. They added simulated muscles to these model skulls to estimate the highest possible bite force. Their model for Proceratosaurus exhibited an estimated bite force of {{convert|390|N|lbf|abbr=on}}, comparable to Dilong, but much lower than those of adult tyrannosaurids. Their results suggested that the skull of Proceratosaurus had a proportionately lower ability to withstand stresses than those of tyrannosaurids, contributing to their low bite force. The crest may have helped to redistribute stress and buttress the skull when biting. The low bite force in combination with the morphology of the skull suggests that Proceratosaurus most likely fed on small-bodied prey.{{cite journal |last1=Johnson-Ransom |first1=E.|last2=Li |first2=F.|last3=Xu |first3=X.|author-link3=Xu Xing (paleontologist)|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 }} Some of the teeth on the lower jaw of the Proceratosaurus holotype display damage likely caused during feeding.

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 a 2016 popular book, pointing 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 age, 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"|left]]

The only known Proceratosaurus specimen was found in rocks of the Great Oolite Group, which date to the late Bathonian age of the Middle Jurassic. The exact stratigraphic layer in which Proceratosaurus was discovered is unknown, but it is probably part of either 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}} or the overlying Forest Marble Formation.{{cite book |last1=Weishampel |first1=D.B. |title=The Dinosauria |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. |publisher=University of California Press |year=2004 |isbn=0-520-24209-2 |editor-last=Weishampel |editor-first=D.B. |edition=2nd |pages=517–606 |chapter=Dinosaur Distribution |editor2-last=Dodson |editor2-first=P. |editor3-last=Osmólska |editor3-first=H.}} The oolitic limestones in which Proceratosaurus was discovered are thought to have formed in very shallow marine conditions on the continental shelf.

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|url-access=subscription }} 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=https://core.ac.uk/download/pdf/15521158.pdf |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.{{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 |journal=British Geological Survey Research Report |volume=11 |issue=6 |pages=1–9 |isbn=9780852726952}} The Great Oolite Group was deposited in conditions varying from shallow marine to paralic (coastal). The coastlines of these islands fluctuated throughout the Bathonian, with areas of shallow marine deposition being sometimes temporarily transformed into lagoonal or terrestrial environments with lakes and ponds, and it has been suggested that animals were able to disperse between them and possibly the Fennoscandian Shield, with many terrestrial vertebrate species found in Bathonian deposits of the Great Oolite Group of England also found in the equivalently aged rocks of the Kilmaluag Formation of the Isle of Skye in northern Scotland.

The flora from the Bathonian-aged Taynton Limestone Formation in Oxfordshire (which is immediately east of Gloucestershire where Proceratosaurus was found) 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, probably representing a 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}} In the White Limestone Formation, evidence of wildfires indicates the periodic occurrence of long periods of drought.{{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}}

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

Other dinosaurs known from the Bathonian age 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 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=4|pages=617–644|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 reptiles |journal=Journal of Vertebrate Paleontology |volume=43 |issue=4 |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 |last1=Panciroli |first1=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 |bibcode=2020EESTR.111..135P |issn=1755-6910}}

The Great Oolite Group is also host to a diverse assemblage of small terrestrial vertebrates (microvertebrates), known from over a dozen localities across England. The most important locality, the Kirtlington Mammal Bed in Oxfordshire, deposited in swampy, coastal conditions at the boundary between the White Limestone and Forest Marble, preserves remains from large animals as well, but the majority are microvertebrates. These include primitive mammals and their close relatives, such as tritylodontid cynodonts, morganucodonts, docodonts, allotherians, haramiyidans, shuotheriids, eutriconodonts, and early-diverging cladotherians.{{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 amphibians, including salamanders, frogs and albanerpetontids as well as reptiles like turtles, lizards (among the world's oldest{{Citation |last=Evans |first=S.E.|author-link=Susan E. Evans |title=The Origin and Early Diversification of Squamates |date=2022-08-11 |work=The Origin and Early Evolutionary History of Snakes |pages=7–25 |editor-last=Gower |editor-first=David J. |url=https://www.cambridge.org/core/product/identifier/9781108938891%23CN-bp-2/type/book_part |access-date=2025-04-27 |edition=1 |publisher=Cambridge University Press |doi=10.1017/9781108938891.004 |isbn=978-1-108-93889-1 |editor2-last=Zaher |editor2-first=Hussam|url-access=subscription }}), choristoderes, and sphenodontians have also been discovered in the Kirtlington Mammal Bed.

{{Reflist}}

{{Theropoda|C.}}

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Category:Proceratosauridae

Category:Dinosaur genera

Category:Bathonian dinosaurs

Category:Taxa named by Friedrich von Huene

Category:Fossil taxa described in 1926

Category:Dinosaurs of the United Kingdom