Proceratosaurusis agenusofcarnivoroustheropoddinosaurfrom theMiddle Jurassic(Bathonian) ofEngland.It contains a single species.P. bradleyi,known from a mostly complete skull and lower jaws.Proceratosauruswas a small dinosaur, estimated to measure around 3 m (9.8 ft) in length.[1][2][3]Its name refers to how it was originally thought to be an ancestor ofCeratosaurus,due to the partially preserved portion of the crest ofProceratosaurussuperficially resembling the small crest ofCeratosaurus.[4]Now, however, it is considered acoelurosaur,specifically a member of the familyProceratosauridae,and amongst the earliest known members of the cladeTyrannosauroidea.[5]
| Proceratosaurus Temporal range:Bathonian,
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| Holotypeskull (NHMUK PV R 4860) | |
Scientific classification
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Clade: | Dinosauria |
| Clade: | Saurischia |
| Clade: | Theropoda |
| Family: | †Proceratosauridae |
| Genus: | †Proceratosaurus von Huene,1926 |
| Species: | †P. bradleyi
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| Binomial name | |
| †Proceratosaurus bradleyi (Woodward,1910 [originallyMegalosaurus])
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| Synonyms | |
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Thetype specimenis held in theNatural History Museumin London and was described in1910fromooliticlimestone of theGreat Oolite GroupnearMinchinhamptonwhile excavating for a reservoir.[6]
History of discovery
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In 1910, the British paleontologistArthur Smith Woodwardreported a partialtheropodskull discovered some time prior by F. Lewis Bradley during excavation for a reservoir atMinchinhampton,a town in theCotswoldsinGloucestershire,England. Bradley hadpreparedthe skull so that the left side was exposed, and submitted it to theGeological Society of London.Woodward made the skull theholotype specimenof a new species ofMegalosaurus(agenusnamed in 1824),M. bradleyi,in honour of its discoverer. At the time it was discovered, it was one of the most complete theropod skulls known from Europe, possibly with the exception of the crushed and hard to interpret skulls ofCompsognathusandArchaeopteryx.Currently the skull is housed at theNatural History Museum,where it is catalogued as specimenNHMUK PV R 4860.The upper part of the skull missing due to afissurethat had eroded the rock and was partially filled withcalcite.[7][1]
In 1923, the German palaeontologistFriedrich von Huenemoved the species to the new genusProceratosaurus,assuming it was the ancestor of the Jurassic genusCeratosaurus,but since the name was only used in a schematic, the name has been considered anomen nudum,an invalidly published name. He validated the name three years later in two 1926 articles by providing a diagnosis 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 sinceCT scannedat theUniversity of Texas,further mechanically prepared to reveal additional details of the skull, jaw, and teeth, and was re-described by the German palaeontologist Oliver W. M. Rauhut and colleagues in 2010.[1][8]
Description
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Proceratosauruswas a small dinosaur. In restudy at 2010, total length of 2.98–3.16 m (9.8–10.4 ft) and body mass of 28–36 kg (62–79 lb) are estimated.[1]Various books estimated it to measure 3–4 m (9.8–13.1 ft) in length and 50–100 kg (110–220 lb) in body mass.[2][3]
Classification
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Arthur Smith Woodward, who initially studiedProceratosaurus,placed it as a species ofMegalosaurus,due to same number of premaxillary teeth (4).[7]Later study during the 1930s byFriedrich von Huenesuggested a closer relationship withCeratosaurus,and Huene thought both dinosaurs represented members of the groupCoelurosauria.[9]
It was not until the late 1980s, afterCeratosaurushad been shown to be a much more primitive theropod and not a coelurosaur, that the classification ofProceratosauruswas again re-examined.Gregory S. Paulsuggested that it was a close relative ofOrnitholestes,again mainly due to the crest on the nose (though the idea thatOrnitholestesbore a nasal crest was later disproved). Paul considered bothProceratosaurusandOrnitholestesto be neither ceratosaurs nor coelurosaurs, but instead primitiveallosauroids.Furthermore, Paul considered the much larger dinosaurPiveteausaurusto be the same genus asProceratosaurus,makingPiveteausaurusa junior synonym.[10]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.[1]
Severalphylogeneticstudies in the early 21st century finally foundProceratosaurus(as well asOrnitholestes) to be a coelurosaur, only distantly related to the ceratosaurids and allosauroids, though one opinion published in 2000 consideredProceratosaurusa ceratosaurid without presenting supporting evidence. Phylogenetic analyses byThomas R. Holtz Jr.in 2004 also placedProceratosaurusamong the coelurosaurs, though with only weak support, and again found an (also weakly supported) close relationship withOrnitholestes.[1]
The first major re-evaluation ofProceratosaurusand its relationships was published in 2010 by Oliver Rauhut and colleagues. Their study concluded thatProceratosauruswas in fact a coelurosaur, and moreover atyrannosauroid,a member of the lineage leading to the giant tyrannosaurs of the Late Cretaceous. Furthermore, they found thatProceratosauruswas most closely related to the Chinese tyrannosauroidGuanlong.They named thecladecontaining these two dinosaurs theProceratosauridae,defined as all theropods closer toProceratosaurusthan toTyrannosaurus,Allosaurus,Compsognathus,Coelurus,Ornithomimus,orDeinonychus.[1][11]
Below is a cladogram from a 2022 study byDarren Naishand Andrea Cau on the genusEotyrannus:[12]
In 2024, the describers ofAlpkarakushrecoveredDilongand proceratosaurids (ProceratosaurusandGuanlong) outside Tyrannosauroidea based on their phylogenetic analysis.[13]
Palaeobiology
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Proceratosauruspossessed a nasal crest, which may have served as a display organ but also possibly served to reduce bending stresses on the skull when biting. This may indicateProceratosaurusused a puncture-pull strategy for hunting prey. However,Proceratosauruswas likely not a big game hunter, lacking the bone-crushing teeth and extremely powerful bites of the tyrannosaurids. Instead, it possessed an elongated skull, commonly found in basal coelurosaurs and basal tyrannosauroids.[1]
Paleoenvironment
editThe flora from the roughly equivalently agedTaynton Limestone Formationin Oxfordshire is dominated byaraucarianandcheirolepidiaceanconifers as well asbennettitaleansandPelourdea,representing a probably seasonally dry coastal environment.[14]Other dinosaurs known from equivalently aged deposits from the Bathonian of Britain include the large theropodMegalosaurus,[15]the sauropodCetiosaurus,[16]as well as indeterminateornithischians[17]andmaniraptorans.[18]A diverse microvertebrate fauna is known from the equivalently agedForest Marble Formation,including frogs, salamanders, turtles,choristoderes,lizards,rhynchocephalians,crocodyliformes, andmammaliamorphsincludingtritylodontids,morganucodonts,docodonts,allotheriansandeutriconodonts.[19]
See also
editReferences
edit- ^abcdefghRauhut, Oliver W. M.; Milner, Angela C.; Moore-Fay, Scott (2010)."Cranial osteology and phylogenetic position of the theropod dinosaurProceratosaurusbradleyi(Woodward, 1910) from the Middle Jurassic of England ".Zoological Journal of the Linnean Society.158:155–195.doi:10.1111/j.1096-3642.2009.00591.x.
- ^abHoltz, Thomas R. Jr. (2008)Dinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All AgesSupplementary Information
- ^abPaul, Gregory S. (2016).The Princeton Field Guide to Dinosaurs.Princeton University Press. p. 105.ISBN978-1-78684-190-2.OCLC985402380.
- ^Palmer, D., ed. (1999).The Marshall Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals.London: Marshall Editions. p. 114.ISBN978-1-84028-152-1.
- ^Holtz, Thomas(December 1998)."A new phylogeny of the carnivorous dinosaurs"(PDF).Gaia.15:5–61.
- ^"Oldest T. rex relative identified".BBC News. 2009-11-04.Retrieved2009-11-04.
- ^abWoodward, A. S. (1910)."On a Skull of Megalosaurus from the Great Oolite of Minchinhampton (Gloucestershire)".Quarterly Journal of the Geological Society.66(1–4): 111–115.doi:10.1144/GSL.JGS.1910.066.01-04.07.S2CID129493139.
- ^Milner, A. C.; Barrett, Paul M. (2016). "Smith Woodward's contributions on fossil tetrapods".Geological Society, London, Special Publications.430(1): 289–309.Bibcode:2016GSLSP.430..289M.doi:10.1144/SP430.13.S2CID131347939.
- ^von Huene, F. (1932). "Die fossile Reptil-Ordnung Saurischia, ihre Entwicklung und Geschichte."Monographien zur Geologie und Palaeontologie (Serie 1),4:1–361.
- ^Paul, G.S. (1988).Predatory Dinosaurs of the World.New York: Simon and Schuster. pp.366–369.ISBN978-0-671-61946-6.
- ^"Oldest T. rex relative identified".2009.Retrieved11 November2021.
- ^Naish, D.; Cau, A. (July 2022)."The osteology and affinities ofEotyrannus lengi,a tyrannosauroid theropod from the Wealden Supergroup of southern England ".PeerJ.10:e12727.doi:10.7717/peerj.12727.PMC9271276.PMID35821895.
- ^Rauhut, Oliver W M; Bakirov, Aizek A; Wings, Oliver; Fernandes, Alexandra E; Hübner, Tom R (2024-08-01)."A new theropod dinosaur from the Callovian Balabansai Formation of Kyrgyzstan".Zoological Journal of the Linnean Society.201(4).doi:10.1093/zoolinnean/zlae090.ISSN0024-4082.
- ^Cleal, C. J.; Rees, P. M. (July 2003)."The Middle Jurassic flora from Stonesfield, Oxfordshire, UK".Palaeontology.46(4): 739–801.Bibcode:2003Palgy..46..739C.doi:10.1111/1475-4983.00319.ISSN0031-0239.S2CID129569932.
- ^Benson, Roger B. J. (April 2010)."A description of Megalosaurus bucklandii (Dinosauria: Theropoda) from the Bathonian of the UK and the relationships of Middle Jurassic theropods".Zoological Journal of the Linnean Society.158(4): 882–935.doi:10.1111/j.1096-3642.2009.00569.x.
- ^Upchurch, Paul; Martin, John (2003-04-11)."The anatomy and taxonomy of Cetiosaurus (Saurischia, Sauropoda) from the Middle Jurassic of England".Journal of Vertebrate Paleontology.23(1): 208–231.doi:10.1671/0272-4634(2003)23[208:TAATOC]2.0.CO;2.ISSN0272-4634.S2CID55360032.
- ^Wills, Simon; Bernard, Emma Louise; Brewer, Philippa; Underwood, Charlie J.; Ward, David J. (April 2019)."Palaeontology, stratigraphy and sedimentology of Woodeaton Quarry (Oxfordshire) and a new microvertebrate site from the White Limestone Formation (Bathonian, Jurassic)".Proceedings of the Geologists' Association.130(2): 170–186.Bibcode:2019PrGA..130..170W.doi:10.1016/j.pgeola.2019.02.003.S2CID135409990.
- ^Wills, Simon; Underwood, Charlie J.; Barrett, Paul M. (March 2023). Mannion, Philip (ed.)."Machine learning confirms new records of maniraptoran theropods in Middle Jurassic UK microvertebrate faunas".Papers in Palaeontology.9(2): e1487.Bibcode:2023PPal....9E1487W.doi:10.1002/spp2.1487.ISSN2056-2799.
- ^"Kirtlington 3p (Mammal Bed)".Paleobiology Database.Retrieved28 August2018.