Spinosauridae

{{short description|Family of dinosaurs}} {{Automatic taxobox | name = Spinosaurids | fossil_range = <br/>Early Cretaceous–Late Cretaceous<br/>(Berriasian–Cenomanian), {{fossil range|earliest=168|140|94}}<small>Possible Bathonian record<ref name="Sharma2023">{{cite journal|last1=Sharma|first1=A.|last2=Novas|first2=Fernando E.|year=2023|title=First Jurassic Evidence of a Possible Spinosaurid Pedal Ungual, from the Jaisalmer Basin, India|journal=Rivista Italiana di Paleontologia e Stratigrafia|volume=29|issue=3|pages=653–670|doi=10.54103/2039-4942/20032|bibcode=2023RIPS..12920032S |doi-access=free}}</ref></small> | image = Spinosauridae Diversity.jpg | image_upright = 1.1 | image_caption = Montage of four spinosaurids, clockwise from top left: ''Baryonyx'', ''Irritator'', ''Spinosaurus'' and ''Suchomimus'' | display_parents = 2 | taxon = Spinosauridae | authority = Stromer, 1915 | type_species = {{extinct}}''Spinosaurus aegyptiacus'' | type_species_authority = Stromer, 1915 | subdivision_ranks = Subgroups and genera | subdivision = *{{extinct}}''Cristatusaurus'' *{{extinct}}''Iberospinus'' *{{extinct}}''Monolophosaurus''?<ref>{{Cite journal |last1=Rauhut |first1=Oliver W M |last2=Bakirov |first2=Aizek A |last3=Wings |first3=Oliver |last4=Fernandes |first4=Alexandra E |last5=Hübner |first5=Tom R |date=2024-08-01 |title=A new theropod dinosaur from the Callovian Balabansai Formation of Kyrgyzstan |journal=Zoological Journal of the Linnean Society |language=en |volume=201 |issue=4 |article-number=zlae090 |doi=10.1093/zoolinnean/zlae090 |issn=0024-4082|doi-access=free }}</ref> *{{extinct}}''Ostafrikasaurus''? *{{extinct}}'''Spinosauria''' <small>Olshevsky, 1991</small><ref>{{cite journal | last = Olshevsky | first = G. | year = 1991 | title = A revision of the parainfraclass Archosauria Cope, 1869, excluding the advanced Crocodylia | url = http://www.miketaylor.org.uk/tmp/Olshevsky_1991_A_revision_of_the_parainfraclass_Archosauria_Cope_1869_excluding_the_advanced_Crocodylia.pdf | journal = Mesozoic Meanderings | volume = 2 | pages = 1–196 | access-date = 14 April 2018 | archive-url = https://web.archive.org/web/20180819050626/http://www.miketaylor.org.uk/tmp/Olshevsky_1991_A_revision_of_the_parainfraclass_Archosauria_Cope_1869_excluding_the_advanced_Crocodylia.pdf | archive-date = 19 August 2018 }}</ref> **{{extinct}}'''Baryonychinae''' ***{{extinct}}''Baryonyx'' ***{{extinct}}''Cristatusaurus''? ***{{extinct}}''Eocarcharia''? ***{{extinct}}''Iberospinus''? ***{{extinct}}''Protathlitis''? ***{{extinct}}''Riojavenatrix'' ***{{extinct}}''Suchosaurus'' ***{{extinct}}'''Ceratosuchopsini''' ****{{extinct}}''Ceratosuchops'' ****{{extinct}}''Eocarcharia''? ****{{extinct}}''Riparovenator'' ****{{extinct}}''Suchomimus'' **{{extinct}}'''Spinosaurinae''' ***{{extinct}}''Camarillasaurus''? ***{{extinct}}''Iberospinus''? ***{{extinct}}''Ichthyovenator'' ***{{extinct}}''Irritator'' ***{{extinct}}''Siamosaurus''? ***{{extinct}}''Vallibonavenatrix'' *** {{extinct}}'''Spinosaurini''' ****{{extinct}}''Oxalaia''* ****{{extinct}}''Sigilmassasaurus''* ****{{extinct}}''Spinosaurus'' <small>*disputed validity; =''Spinosaurus''?</small><ref name="Ibrahim_et_al_2014">{{cite journal|last1=Ibrahim|first1=Nizar|author-link=Nizar Ibrahim|last2=Sereno|first2=Paul C.|last3=Dal Sasso|first3=Cristiano|last4=Maganuco|first4=Simone|last5=Fabri|first5=Matteo|last6=Martill|first6=David M.|last7=Zouhri|first7=Samir|last8=Myhrvold|first8=Nathan|last9=Lurino|first9=Dawid A.|date=2014|title=Semiaquatic adaptations in a giant predatory dinosaur|url=https://researchportal.port.ac.uk/portal/en/publications/semiaquatic-adaptations-in-a-giant-predatory-dinosaur(8f11a1ce-3265-4b3b-8c81-6f576856a87f).html|journal=Science|volume=345|issue=6204|pages=1613–6|bibcode=2014Sci...345.1613I|doi=10.1126/science.1258750|pmid=25213375|s2cid=34421257|doi-access=free}} [https://www.science.org/doi/10.1126/science.1258750 Supplementary Information]</ref><ref name=Symthetal2020>{{cite journal |last1=Smyth |first1=Robert S.H. |last2=Ibrahim |first2=Nizar |last3=Martill |first3=David M. |title=Sigilmassasaurus is Spinosaurus: A reappraisal of African spinosaurines |journal=Cretaceous Research |date=October 2020 |volume=114 |article-number=104520 |doi=10.1016/j.cretres.2020.104520 |bibcode=2020CrRes.11404520S |s2cid=219487346 }}</ref><ref name="Sereno Beck Dutheil et al 1998"/> | synonyms = * Baryonychidae <small>Charig & Milner, 1986</small> * Irritatoridae <small>Martill et al., 1996</small> * Sigilmassasauridae <small>Russell, 1996</small> }} '''Spinosauridae''' (or '''spinosaurids''') is a clade or family of tetanuran theropod dinosaurs comprising ten to seventeen known genera. Spinosaurid fossils have been recovered worldwide, including Africa, Europe, South America, and Asia. Their remains have generally been attributed to the Early to Late Cretaceous.

Spinosaurids were large bipedal carnivores. Their crocodilian-like skulls were long, low, and narrow, bearing conical teeth with reduced or absent serrations. The tips of their upper and lower jaws fanned out into a spoon-shaped structure similar to a rosette, behind which there was a notch in the upper jaw that the expanded tip of the lower jaw fit into. The nostrils of spinosaurids were retracted to a position further back on the head than in most other theropods, and they had bony crests on their heads along the midline of their skulls. Their robust shoulders wielded stocky forelimbs, with three-fingered hands that bore an enlarged claw on the first digit. In many species, the upwards-projecting neural spines of the vertebrae (backbones) were significantly elongated and formed a sail on the animal's back (hence the family's etymology), which supported either a layer of skin or a fatty hump.

The genus ''Spinosaurus'', from which the family, one of its subfamilies (Spinosaurinae) and tribe (Spinosaurini) take their names, is among the largest known terrestrial predators from the fossil record, with an estimated length of up to {{Convert|14|m|sp=us}}<ref>{{Cite web |last=Sereno |first=Paul C. |last2=Myhrvold |first2=Nathan |last3=Henderson |first3=Donald M. |last4=Fish |first4=Frank E. |last5=Vidal |first5=Daniel |last6=Baumgart |first6=Stephanie L. |last7=Keillor |first7=Tyler M. |last8=Formoso |first8=Kiersten K. |last9=Conroy |first9=Lauren L. |date=2022-11-30 |title=Spinosaurus is not an aquatic dinosaur |url=https://elifesciences.org/articles/80092 |access-date=2026-03-08 |website=eLife |language=en}}</ref> and body mass of up to {{convert|7.4|MT|ST}}<ref>{{Cite web |last=Sereno |first=Paul C. |last2=Myhrvold |first2=Nathan |last3=Henderson |first3=Donald M. |last4=Fish |first4=Frank E. |last5=Vidal |first5=Daniel |last6=Baumgart |first6=Stephanie L. |last7=Keillor |first7=Tyler M. |last8=Formoso |first8=Kiersten K. |last9=Conroy |first9=Lauren L. |date=2022-11-30 |title=Spinosaurus is not an aquatic dinosaur |url=https://elifesciences.org/articles/80092 |access-date=2026-03-08 |website=eLife |language=en}}</ref> (similar to the weight of an African elephant). The closely related genus ''Sigilmassasaurus'' may have reached a similar or greater size, though its taxonomy is disputed. Direct fossil evidence and anatomical adaptations indicate that spinosaurids were at least partially piscivorous (fish-eating), with additional fossil finds indicating they also fed on other dinosaurs and pterosaurs. The osteology of spinosaurid teeth and bones has suggested a semiaquatic lifestyle for some members of this clade. This is further indicated by various anatomical adaptations, such as retracted eyes and nostrils; and the deepening of the tail in some taxa, which has been suggested to have aided in underwater propulsion akin to that of modern crocodilians. Spinosaurs are proposed to be closely related to the megalosaurid theropods of the Jurassic. This is due to both groups sharing many features such an enlarged claw on their first manual ungual and an elongated skull.<ref>{{cite journal |last1=Benson |first1=Rodger |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 |date=2010 |volume=158 |issue=4 |pages=882–935 |doi=10.1111/j.1096-3642.2009.00569.x |s2cid=84266680 |doi-access=free }}</ref> However, some propose that this group (which is known as the Megalosauroidea) is paraphyletic and that spinosaurs represent either the most basal tetanurans<ref>{{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|archive-date=2011-07-19|access-date=2008-11-28|archive-url=https://web.archive.org/web/20110719060449/http://www.mnhn.ul.pt/geologia/gaia/1.pdf|url-status=live}}</ref> or the basal carnosaurs which are less derived than the megalosaurids.<ref>{{cite journal |last1=Rauhut |first1=Oliver |title=Probable basal allosauroid from the early Middle Jurassic Cañadón Asfalto Formation of Argentina highlights phylogenetic uncertainty in tetanuran theropod dinosaurs |journal=Scientific Reports |date=2019 |volume=9 |issue=18826 |article-number=18826 |doi=10.1038/s41598-019-53672-7 |pmid=31827108 |pmc=6906444 |bibcode=2019NatSR...918826R }}</ref> Some have proposed a combination of the two ideas with spinosaurs being in a monophyletic Megalosauroidea inside a more inclusive Carnosauria that is made up of both allosauroids and megalosauroids.<ref>{{cite journal |last1=Rauhut |first1=Oliver |title=Exceptionally preserved juvenile megalosauroid theropod dinosaur with filamentous integument from the Late Jurassic of Germany |journal=PNAS |date=2012 |volume=109 |issue=29 |pages=11746–11751 |doi=10.1073/pnas.1203238109 |pmid=22753486 |pmc=3406838 |bibcode=2012PNAS..10911746R |doi-access=free }}</ref>

== History of discovery == [[File:Spinosaurus_holotype.jpg|thumb|Elements of the holotype specimen of ''Spinosaurus aegyptiacus'', as illustrated by Ernst Stromer in 1915|alt=|left]]

The first spinosaurid fossil, a single conical tooth, was discovered circa 1820 by British paleontologist Gideon Mantell in the Wadhurst Clay Formation.<ref>{{cite book |last1=Mantell |first1=Gideon Algernon |title=The fossils of the South Downs or, Illustrations of the geology of Sussex. |date=1822 |publisher=L. Relfe |oclc=754552732 |doi=10.5962/bhl.title.44924 |url=https://www.biodiversitylibrary.org/item/97604 }}{{page needed|date=April 2022}}</ref> In 1841, naturalist Sir Richard Owen mistakenly assigned it to a crocodilian he named ''Suchosaurus'' (meaning "crocodile lizard").<ref name="owen1841">Owen, R. (1840–1845). ''Odontography''. London: Hippolyte Baillière, 655 pp, 1–32</ref><ref>Owen, R., 1842, ''Report on British fossil reptiles. Part II''. Reports of the meetings of the British Association for the Advancement of Science. 11, pp 61-204</ref> A second species, ''S. girardi'', was later named in 1897.<ref name="sauvage1897">Sauvage, H. E. (1897–1898). ''Vertébrés fossiles du Portugal. Contribution à l'étude des poissons et des reptiles du Jurassique et du Crétacique.'' Lisbonne: Direction des Travaux géologiques du Portugal, 46p</ref> However, the spinosaurid nature of ''Suchosaurus'' was not recognized until a 1998 redescription of ''Baryonyx.''<ref>Milner, A., 2003, "Fish-eating theropods: A short review of the systematics, biology and palaeobiogeography of spinosaurs". In: Huerta Hurtado and Torcida Fernandez-Baldor (eds.). ''Actas de las II Jornadas Internacionales sobre Paleontologýa de Dinosaurios y su Entorno (2001)''. pp 129-138</ref>

The first fossils referred to a spinosaurid were discovered in 1912 at the Bahariya Formation in Egypt. Consisting of vertebrae, skull fragments, and teeth, these remains became the holotype specimen of the new genus and species ''Spinosaurus aegyptiacus'' in 1915, when they were described by German paleontologist Ernst Stromer. The dinosaur's name meant "Egyptian spine lizard", in reference to the unusually long neural spines not seen previously in any other theropod. In April 1944, the holotype of ''S. aegyptiacus'' was destroyed during an allied bombing raid in World War II.<ref>{{cite journal |last1=Smith |first1=Joshua B. |last2=Lamanna |first2=Matthew C. |last3=Mayr |first3=Helmut |last4=Lacovara |first4=Kenneth J. |title=New Information Regarding the Holotype of Spinosaurus Aegyptiacus Stromer, 1915 |journal=Journal of Paleontology |date=March 2006 |volume=80 |issue=2 |pages=400–406 |doi=10.1666/0022-3360(2006)080[0400:NIRTHO]2.0.CO;2 |s2cid=130989487 }}</ref><ref name=Hone2017>{{cite journal |last1=Hone |first1=David William Elliott |last2=Holtz |first2=Thomas Richard |title=A Century of Spinosaurs - A Review and Revision of the Spinosauridae with Comments on Their Ecology |journal=Acta Geologica Sinica - English Edition |date=June 2017 |volume=91 |issue=3 |pages=1120–1132 |doi=10.1111/1755-6724.13328 |bibcode=2017AcGlS..91.1120H |s2cid=90952478 |url=http://qmro.qmul.ac.uk/xmlui/handle/123456789/49404 |url-access=subscription }}</ref> In 1934, Stromer referred a partial skeleton also from the Bahariya Formation to a new species of ''Spinosaurus;''<ref name="stromer34">{{cite journal|last=Stromer|first=E.|author-link=Ernst Stromer|year=1934|title=Ergebnisse der Forschungsreisen Prof. E. Stromers in den Wüsten Ägyptens. II. Wirbeltier-Reste der Baharije-Stufe (unterstes Cenoman). 13. Dinosauria|journal=Abhandlungen der Bayerischen Akademie der Wissenschaften Mathematisch-naturwissenschaftliche Abteilung |series=Neue Folge|language=de|volume=22|pages=1–79}}</ref> the specimen has since been alternatively assigned to another African spinosaurid, ''Sigilmassasaurus.''<ref name="Evers-2015">{{cite journal |last1=Evers |first1=Serjoscha W. |last2=Rauhut |first2=Oliver W.M. |last3=Milner |first3=Angela C. |last4=McFeeters |first4=Bradley |last5=Allain |first5=Ronan |title=A reappraisal of the morphology and systematic position of the theropod dinosaur Sigilmassasaurus from the 'middle' Cretaceous of Morocco |journal=PeerJ |date=20 October 2015 |volume=3 |article-number=e1323 |doi=10.7717/peerj.1323 |pmid=26500829 |pmc=4614847 |doi-access=free }}</ref>

In 1983, a relatively complete skeleton was excavated from the Smokejacks pit in Surrey, England. These remains were described by British paleontologists Alan J. Charig and Angela C. Milner in 1986 as the holotype of a new species, ''Baryonyx walkeri.'' After the discovery of ''Baryonyx,'' many new genera have since been described, with the majority from very incomplete remains. However, other finds bear enough fossil material and distinct anatomical features to be assigned with confidence. Paul Sereno and colleagues described ''Suchomimus'' in 1998'','' a baryonychine from Niger, on the basis of a partial skeleton found in 1997. In 2004, partial jaw bones were recovered from the Alcântara Formation, these were referred to a new genus of spinosaurine named ''Oxalaia'' in 2011 by Alexander Kellner.<ref name=Hone2017/>

Fragmentary remains belonging to a large spinosaurid were collected in 2021 from the Vectis Formation on the Isle of Wight. The material lacks distinct characteristics that would prompt the erection of a new species. However, the size of the bones is comparable to the size of ''Spinosaurus'', making the "White Rock spinosaurid" one of the largest theropods ever found in Europe in addition to the first theropod identified in the Vectis Formation.<ref>{{Cite journal |last1=Barker |first1=CT |last2=Lockwood |first2=JAF |last3=Naish |first3=D |last4=Brown |first4=S |last5=Hart |first5=A |last6=Tulloch |first6=E |last7=Gostling |first7=NJ |title=A European giant: a large spinosaurid (Dinosauria: Theropoda) from the Vectis Formation (Wealden Group, Early Cretaceous), UK |url=https://peerj.com/articles/13543/ |journal=PeerJ |publication-date=2022 |volume=10 |article-number=e13543 |doi=10.7717/peerj.13543 |doi-access=free |pmid=35702254 |pmc=9188774 }}</ref><ref>{{Cite news |last=Haq |first=Sana Noor |date=June 9, 2022 |title=Scientists unearth remains of one of Europe's biggest predatory dinosaurs |url=https://www.cnn.com/2022/06/09/europe/spinosaurid-dinosaur-europe-intl-scn-scli/index.html |access-date=January 21, 2026 |work=CNN}}</ref>

In 2024, ''Riojavenatrix lacustris'' became the fifth spinosaurid species to be named from material found in the Iberian Peninsula, following ''Camarillasaurus'', ''Iberospinus'', ''Protathlitis'', and ''Vallibonavenatrix''. The fossils hail from the Early Cretaceous Enciso Group of La Rioja, Spain.<ref>{{Cite journal |last1=Isasmendi |first1=E |last2=Cuesta |first2=E |last3=Díaz-Martínex |first3=I |last4=Company |first4=J |last5=Sáez-Benito |first5=P |last6=Viera |first6=LI |last7=Torices |first7=A |last8=Pereda-Suberbiola |first8=X |title=Increasing the theropod record of Europe: a new basal spinosaurid from the Enciso Group of the Cameros Basin (La Rioja, Spain). Evolutionary implications and palaeobiodiversity |url=https://academic.oup.com/zoolinnean/article/202/3/zlad193/7564790?login=false |journal=Zoological Journal of the Linnean Society |volume=202 |issue=3}}</ref><ref>{{cite web|title=Researchers discover a new species of carnivorous dinosaur in La Rioja, Spain|url=https://phys.org/news/2024-03-species-carnivorous-dinosaur-la-rioja.html|date=13 March 2024|access-date=25 May 2024|website=Phys.org}}</ref>

In 2026, Paul Sereno and colleagues described ''Spinosaurus mirabilis'', a new species of ''Spinosaurus'' from the Farak Formation of Niger.<ref name="Sereno2026">{{Cite journal |last1=Sereno |first1=Paul C. |author1-link=Paul Sereno |last2=Vidal |first2=Daniel |last3=Myhrvold |first3=Nathan P. |author3-link=Nathan Myhrvold |last4=Johnson-Ransom |first4=Evan |last5=Ciudad Real |first5=María |last6=Baumgart |first6=Stephanie L. |last7=Sánchez Fontela |first7=Noelia |last8=Green |first8=Todd L. |last9=Saitta |first9=Evan T. |last10=Adamou |first10=Boubé |last11=Bop |first11=Lauren L. |last12=Keillor |first12=Tyler M. |last13=Fitzgerald |first13=Erin C. |last14=Dutheil |first14=Didier B. |last15=Laroche |first15=Robert A. S. |last16=Demers-Potvin |first16=Alexandre V. |last17=Simarro |first17=Álvaro |last18=Gascó-Lluna |first18=Francesc |last19=Lázaro |first19=Ana |last20=Gamonal |first20=Arturo |last21=Beightol |first21=Charles V. |last22=Reneleau |first22=Vincent |last23=Vautrin |first23=Rachel |last24=Bertozzo |first24=Filippo |last25=Granados |first25=Alejandro |last26=Kinney-Broderick |first26=Grace |last27=Mallon |first27=Jordan C. |last28=Lindoso |first28=Rafael M. |last29=Ramezani |first29=Jahandar |display-authors=10 |date=February 19, 2026 |title=Scimitar-crested ''Spinosaurus'' species from the Sahara caps stepwise spinosaurid radiation |journal=Science |volume=391 |issue=6787 |doi=10.1126/science.adx5486 |pages=1–10 |issn=0036-8075}}</ref>

==Description== [[File:Spinosauridae_Size_Diagram_by_PaleoGeek_-_Version_2.svg|thumb|upright=1.3|left|Size comparison of spinosaurid genera (from left to right) ''Irritator'', ''Baryonyx'', ''Oxalaia'', ''Spinosaurus'', ''Suchomimus'', and ''Ichthyovenator'' with a human|alt=]]

Although reliable size and weight estimates for most known spinosaurids are hindered by the lack of good material, all known spinosaurids were large animals.<ref name=Hone2017/> The smallest genus known from good material is ''Irritator'', which was between {{Convert|6 and 8|m|ft|abbr=off|sp=us}} long and around {{Convert|1|t|ST + LT|abbr=off|sp=us|lk=on}} in weight.<ref>{{Cite book|url=https://archive.org/details/ultimateguidetod0000dixo|url-access=registration|title=The Ultimate Guide to Dinosaurs|last=Dixon|first=Dougal|date=2009|publisher=Ticktock Books|isbn=978-1-84696-988-1|language=en}}</ref><ref name="Holtz20082">Holtz, Thomas R. Jr. (2011) ''Dinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages,'' [http://www.geol.umd.edu/~tholtz/dinoappendix/HoltzappendixWinter2010.pdf Winter 2010 Appendix.]</ref> ''Ichthyovenator'', ''Baryonyx'', and ''Suchomimus'' ranged from {{Convert|7.5 to 11|m|ft|abbr=on|sp=us}} long, and weighed between {{Convert|1 and 5.2|t|ST + LT|abbr=on|sp=us}}.<ref name="S.-2016">{{Cite book |last=S. |first=Paul, Gregory |title=The Princeton field guide to dinosaurs |date=2016-10-25 |isbn=978-1-4008-8314-1 |edition=2nd |location=Princeton, N.J. |oclc=954055249}}</ref><ref name="Holtz20082" /><ref>{{cite journal |last1=Therrien |first1=François |last2=Henderson |first2=Donald M. |title=My theropod is bigger than yours … or not: estimating body size from skull length in theropods |journal=Journal of Vertebrate Paleontology |date=12 March 2007 |volume=27 |issue=1 |pages=108–115 |doi=10.1671/0272-4634(2007)27[108:mtibty]2.0.co;2 |s2cid=86025320 }}</ref> ''Oxalaia'' may have reached a length of between {{convert|12|and|14|m|ft|0|abbr=on}} and a weight of {{convert|5|to|7|t|ST + LT|abbr=on}}.<ref name="DiscOxalaia">{{cite journal |last1=Kellner |first1=Alexander WA. |last2=Azevedo |first2=Sergio A.K. |last3=Machado |first3=Elaine B. |last4=Carvalho |first4=Luciana B. de |last5=Henriques |first5=Deise D.R. |title=A new dinosaur (Theropoda, Spinosauridae) from the Cretaceous (Cenomanian) Alcântara Formation, Cajual Island, Brazil |journal=Anais da Academia Brasileira de Ciências |date=March 2011 |volume=83 |issue=1 |pages=99–108 |doi=10.1590/S0001-37652011000100006 |pmid=21437377 |doi-access=free |bibcode=2011AnABC..83...99K }}</ref> The largest known genus is ''Spinosaurus'', which was capable of reaching lengths of {{convert|14|m|ft|abbr=on}} and weighed around {{convert|7.4|t|ST + LT|abbr=on}}, making it among the largest known theropod dinosaurs and terrestrial predators.<ref name="Sereno_et_al_2022">{{cite journal |doi=10.7554/eLife.80092 |doi-access=free |title=Spinosaurus is not an aquatic dinosaur |year=2022 |last1=Sereno |first1=Paul C. |last2=Myhrvold |first2=Nathan |last3=Henderson |first3=Donald M. |last4=Fish |first4=Frank E. |last5=Vidal |first5=Daniel |last6=Baumgart |first6=Stephanie L. |last7=Keillor |first7=Tyler M. |last8=Formoso |first8=Kiersten K. |last9=Conroy |first9=Lauren L. |journal=eLife |volume=11 |pmid=36448670 |pmc=9711522 |article-number=e80092}}</ref> The closely allied ''Sigilmassasaurus'' may have grown to a similar or greater length, though its taxonomic relationship with ''Spinosaurus'' is uncertain.<ref name="arden2018">{{cite journal|last1=Arden|first1=T.M.S.|last2=Klein|first2=C.G.|last3=Zouhri|first3=S.|last4=Longrich|first4=N.R.|year=2018|title=Aquatic adaptation in the skull of carnivorous dinosaurs (Theropoda: Spinosauridae) and the evolution of aquatic habits in ''Spinosaurus''|journal=Cretaceous Research|volume=93|pages=275–284|doi=10.1016/j.cretres.2018.06.013|bibcode=2019CrRes..93..275A |s2cid=134735938}}</ref> This consistency in large body size among spinosaurids could have evolved as a byproduct of their preference for semiaquatic lifestyles, as without the need to compete with other large theropod dinosaurs for food, they would have been able to grow to massive lengths.<ref name="Aureliano Ghilardi Buck et al 2018">{{cite journal |last1=Aureliano |first1=Tito |last2=Ghilardi |first2=Aline M. |last3=Buck |first3=Pedro V. |last4=Fabbri |first4=Matteo |last5=Samathi |first5=Adun |last6=Delcourt |first6=Rafael |last7=Fernandes |first7=Marcelo A. |last8=Sander |first8=Martin |title=Semi-aquatic adaptations in a spinosaur from the Lower Cretaceous of Brazil |journal=Cretaceous Research |date=October 2018 |volume=90 |pages=283–295 |doi=10.1016/j.cretres.2018.04.024 |bibcode=2018CrRes..90..283A |s2cid=134353898 |url=http://paleorxiv.org/mjt95/ }}</ref>

===Skull === thumb|upright=1.3|Annotated skull diagram of ''Spinosaurus''|alt=

Spinosaurid skulls—similar in many respects to those of crocodilians—were long, low and narrow.<ref name=Hone2017/> As in other theropods, various fenestrae (openings) in the skull aided in reducing its weight. In spinosaurs however, the antorbital fenestrae were greatly reduced, akin to those of crocodilians.<ref name="rayfieldetal2007"/> The tips of the premaxillae (frontmost snout bones) were expanded in a spoon shape, forming what has been called a "terminal rosette" of enlarged teeth. Behind this expansion, the upper jaw had a notch bearing significantly smaller teeth, into which the also expanded tips of the dentaries (tooth bearing bones of the mandible) fit into, with a notch behind the expansion of the dentary.<ref name=Hone2017/> The maxillae (main upper jaw bones) were long and formed a low branch under the nostrils that connected to the rear of the premaxillae. The teeth at the frontmost part of the maxillae were small, becoming significantly larger soon after and then gradually decreasing in size towards the back of the jaw.<ref name="Sues-2002" /> Analysis of the teeth of spinosaurids and their comparison to the teeth of tyrannosaurids suggest that the deep roots of spinosaurids helped to better anchor the teeth of these animals and distribute the stress against lateral forces generated during bites in predation and feeding scenarios.<ref>{{cite book |last1=Holtz |first1=Thomas R. |title=Tyrannosaurus Rex, the Tyrant King |chapter=A critical reappraisal of the obligate scavenging hypothesis for Tyrannosaurus rex and other tyrant dinosaurs |year=2008 |pages=371–396 |publisher=Indiana University Press |isbn=978-0-253-35087-9 |chapter-url=https://books.google.com/books?id=5WH9RnfKco4C&pg=PA371 }}</ref>

thumb|Closeup of the teeth of ''Suchomimus''|alt=|left

Despite their highly modified skulls, analysis of the endocasts of ''Baryonyx walkeri'' and ''Ceratosuchops inferodios'' reveals spinosaurid brains shared a high degree of similarity with those of other non-maniraptoriform theropods.<ref>{{cite journal |last1=Barker |first1=Chris Tijani |last2=Naish |first2=Darren |last3=Trend |first3=Jacob |last4=Michels |first4=Lysanne Veerle |last5=Witmer |first5=Lawrence |last6=Ridgley |first6=Ryan |last7=Rankin |first7=Katy |last8=Clarkin |first8=Claire E. |last9=Schneider |first9=Philipp |last10=Gostling |first10=Neil J. |year=2023 |title=Modified skulls but conservative brains? The palaeoneurology and endocranial anatomy of baryonychine dinosaurs (Theropoda: Spinosauridae) |journal=Journal of Anatomy |volume=242 |issue=6 |pages=1124–1145 |doi=10.1111/joa.13837 |pmid=36781174 |pmc=10184548 |s2cid=256845477 }}</ref>

Lengthwise atop their skulls ran a thin and shallow sagittal crest that was usually tallest near or above the eyes, either becoming shorter or disappearing entirely towards the front of the head.<ref name=Hone2017/><ref name="Sasso Maganuco Buffetaut Mendez 2005">{{cite journal |last1=Sasso |first1=Cristiano Dal |last2=Maganuco |first2=Simone |last3=Buffetaut |first3=Eric |last4=Mendez |first4=Marco A. |title=New information on the skull of the enigmatic theropod Spinosaurus , with remarks on its size and affinities |journal=Journal of Vertebrate Paleontology |date=30 December 2005 |volume=25 |issue=4 |pages=888–896 |doi=10.1671/0272-4634(2005)025[0888:NIOTSO]2.0.CO;2 |s2cid=85702490 }}</ref><ref name="salesschultz" /> ''Spinosaurus''<nowiki/>'s head crest was comb-shaped and bore distinct vertical grooves,<ref name="Sasso Maganuco Buffetaut Mendez 2005"/> while those of ''Baryonyx'' and ''Suchomimus'' looked like small triangular bumps.<ref name="charigmilner19973">{{Cite journal|last1=Charig|first1=A. J.|last2=Milner|first2=A. C.|year=1997|title=''Baryonyx walkeri'', a fish-eating dinosaur from the Wealden of Surrey|url=http://biostor.org/reference/110558|journal=Bulletin of the Natural History Museum of London|volume=53|pages=11–70}}</ref><ref name="Sereno Beck Dutheil et al 1998"/> ''Irritator''{{'}}s median crest stopped above and behind the eyes in a bulbous, flattened shape. However, given that no fully preserved skulls are known for the genus, the complete shape of ''Irritator''<nowiki/>'s crest is unknown.<ref name="Sues-2002">{{Cite journal|last1=Sues|first1=H. D.|last2=Frey|first2=E.|last3=Martill|first3=D. M.|last4=Scott|first4=D. M.|year=2002|title=Irritator challengeri, a spinosaurid (Dinosauria: Theropoda) from the Lower Cretaceous of Brazil|journal=Journal of Vertebrate Paleontology|volume=22|issue=3|pages=535–547|doi=10.1671/0272-4634(2002)022[0535:ICASDT]2.0.CO;2|s2cid=131050889 }}</ref> ''Cristatusaurus'' and ''Suchomimus'' (a possible synonym of the former) both had narrow premaxillary crests.<ref name="HendrickxMateusandBuffetaut2016"/> ''Angaturama'' (a possible synonym of ''Irritator'') had an unusually tall crest on its premaxillae that nearly overhung the tip of the snout with a small forward protrusion.<ref name="salesschultz" />

Spinosaurid nostrils were set far back on the skull, at least behind the teeth of the premaxillae, instead of at the front of the snout as in most theropods.<ref name=Hone2017/> Those of ''Baryonyx'' and ''Suchomimus'' were large and started between the first and fourth maxillary teeth, while ''Spinosaurus''<nowiki/>'s nostrils were far smaller and more retracted. ''Irritator''<nowiki/>'s nostrils were positioned similarly to those of ''Baryonyx'' and ''Suchomimus'', and were between those of ''Spinosaurus'' and ''Suchomimus'' in size.<ref name="salesschultz" /> Spinosaurids had long secondary palates, bony and rugose structures on the roof of their mouths that are also found in extant crocodilians, but not in most theropod dinosaurs.<ref name="rayfieldetal2007">{{cite journal |last1=Rayfield |first1=Emily J. |last2=Milner |first2=Angela C. |last3=Xuan |first3=Viet Bui |last4=Young |first4=Philippe G. |title=Functional morphology of spinosaur 'crocodile-mimic' dinosaurs |journal=Journal of Vertebrate Paleontology |date=12 December 2007 |volume=27 |issue=4 |pages=892–901 |doi=10.1671/0272-4634(2007)27[892:FMOSCD]2.0.CO;2 |s2cid=85854809 }}</ref> ''Oxalaia'' had a particularly elaborate secondary palate, while most spinosaurs had smoother ones.<ref name="DiscOxalaia" /> The teeth of spinosaurids were conical, with an oval to circular cross section and either absent or very fine serrations. Their teeth ranged from slightly recurved, such as those of ''Baryonyx'' and ''Suchomimus'', to straight, such as those of ''Spinosaurus'' and ''Siamosaurus'', and the crown was often ornamented with longitudinal grooves or ridges.<ref name="salesschultz" /><ref>{{cite journal |last1=Bertin |first1=Tor |title=A Catalogue of Material and Review of the Spinosauridae |journal=PalArch's Journal of Vertebrate Palaeontology |date=2010 |volume=7 |issue=4 |pages=01–39 |url=https://archives.palarch.nl/index.php/jvp/article/view/457 }}</ref>

=== Postcranial skeleton === {{multiple image | align = right | total_width = 320 | image1 = MN_4819-V_manus_skeletal_by_PaleoGeek.png | alt1 = | caption1 = Hand of spinosaurid specimen MN-4819-V (possibly belonging to ''Angaturama''); note the enlarged condition of the first claw | image2 = Spinosaurus foot restoration.JPG | alt2 = | caption2 = Reconstructed foot bones of ''Spinosaurus''; note the straight claws and enlarged hallux (first toe) touching the ground | footer = | direction = }}

The coracoid bones of the shoulders in spinosaurids were robust and hook shaped.<ref name="Sereno Beck Dutheil et al 1998"/> The arms were relatively large and well-built; the radius (long bone of the forearm) was stout and usually only half as long as the humerus (upper arm bone). ''Suchomimus'' is the only spinosaur known to have preserved a furcula (wishbone), which shows that spinosaurs had a V-shaped furcula.<ref name="Lipkin2007">{{cite journal |last1=Lipkin |first1=Christine |last2=Paul |last3=Sereno |first3=Callistus |last4=Horner |first4=Jack |year=2007 |title=The furcula in ''Suchomimus tenerensis'' and ''Tyrannosaurus rex'' (Dinosauria: Theropoda: Tetanurae) |journal=Journal of Paleontology |volume=81 |issue=6 |pages=1523–1527 |doi=10.1666/06-024.1 |bibcode=2007JPal...81.1523L |s2cid=86234363 |url=http://publication.plazi.org/id/BA62FFDAFFCCFFB5FFFFFFA2FFDFFFD2 }}</ref> Spinosaurid hands had three fingers, typical of tetanurans, and wielded an enlarged ungual on the first finger (or "thumb"), which formed the bony core of a keratin claw. In genera like ''Baryonyx'' and ''Suchomimus'', the phalanges (finger bones) were of conventional length for large theropods, and bore hook-shaped, strongly curved hand claws.<ref name=Hone2017/><ref name="S.-2016" /> Based on fragmentary material from the forelimbs of ''Spinosaurus'', it appears to have had longer, more gracile hands and straighter claws than other spinosaurids.<ref name="Spinosaurus 2014">{{Cite journal |last1=Ibrahim |first1=N. |author-link=Nizar Ibrahim |last2=Sereno |first2=P. C. |last3=Dal Sasso |first3=C. |last4=Maganuco |first4=S. |last5=Fabbri |first5=M. |last6=Martill |first6=D. M. |last7=Zouhri |first7=S. |last8=Myhrvold |first8=N. |last9=Iurino |first9=D. A. |year=2014 |title=Semiaquatic adaptations in a giant predatory dinosaur |url=https://researchportal.port.ac.uk/portal/en/publications/semiaquatic-adaptations-in-a-giant-predatory-dinosaur(8f11a1ce-3265-4b3b-8c81-6f576856a87f).html |journal=Science |volume=345 |issue=6204 |pages=1613–1616 |bibcode=2014Sci...345.1613I |doi=10.1126/science.1258750 |pmid=25213375 |s2cid=34421257|doi-access=free }}</ref>

The hindlimbs of ''Suchomimus'' and ''Baryonyx'' were somewhat short and mostly conventional of other megalosauroid theropods.<ref name=Hone2017/><ref name="S.-2016" /> ''Ichthyovenator''<nowiki/>'s hip region was reduced, having the shortest pubis (pubic bone) and ischium (lower and rearmost hip bone) in proportion to the ilium (main hip bone) of any other known theropod.<ref name="AXRK122" /> ''Spinosaurus'' had an even smaller pelvis and hindlimbs in proportion to its body size; its legs composed just over 25 percent of the total body length. Substantially complete spinosaurid foot remains are only known from ''Spinosaurus''. Unlike most theropods—which walk on three toes, with the hallux (first toe) being reduced and elevated off the ground—''Spinosaurus'' walked on four functional toes, with an enlarged hallux that came in contact with the ground. The unguals of its feet, in contrast with the deeper, smaller and recurved unguals of other theropods, were shallow, long, large in relation to the foot, and had flat bottoms. Based on comparisons with those of modern shorebirds, it is theorized to be probable that the ''Spinosaurus''<nowiki/>'s feet were webbed.<ref name="Spinosaurus 2014" />

[[File:Spinosauridae sail comparison.png|alt=|thumb|left|Reconstructed neural spine sails of four spinosaurids; clockwise from top left: ''Spinosaurus'', ''Irritator'', ''Ichthyovenator'', and ''Suchomimus''.]]

The upward-projecting neural spines of spinosaurid vertebrae (backbones) were very tall, more so than in most theropods. In life, these spines would have been covered in skin or fat tissue and formed a sail down the animal's back, a condition that has also been observed in some carcharodontosaurid and ornithopod dinosaurs.<ref name=Hone2017/><ref name="acrocr">{{cite journal|last1=Eddy|first1=DR|last2=Clarke|first2=JA|date=2011|title=New Information on the Cranial Anatomy of ''Acrocanthosaurus atokensis'' and Its Implications for the Phylogeny of Allosauroidea (Dinosauria: Theropoda)|journal=PLOS ONE|volume=6|issue=3|article-number=e17932|doi=10.1371/journal.pone.0017932|pmc=3061882|pmid=21445312|bibcode=2011PLoSO...617932E|doi-access=free}}</ref> The eponymous neural spines of ''Spinosaurus'' were extremely tall, measuring over {{Convert|1|m||abbr=on}} in height on some of the dorsal (back) vertebrae.<ref name="Hecht1998">Hecht, Jeff. 1998. "Fish Swam in Fear." New Scientist. November 21. https://www.newscientist.com/article/mg16021610-300-fish-swam-in-fear/. </ref> ''Suchomimus'' had a lower, ridge-like sail across the majority of its back, hip, and tail region.<ref name="Sereno Beck Dutheil et al 1998"/> ''Baryonyx'' showed a reduced sail, with a few of the rearmost vertebral spines being somewhat elongated.<ref name="charigmilner19973"/> ''Ichthyovenator'' had a sinusoidal (wave-like) sail that was separated in two over the hips, with the upper ends of some neural spines being broad and fan-shaped.<ref name="AXRK122">{{Cite journal|last1=Allain|first1=R.|last2=Xaisanavong|first2=T.|last3=Richir|first3=P.|last4=Khentavong|first4=B.|year=2012|title=The first definitive Asian spinosaurid (Dinosauria: Theropoda) from the early cretaceous of Laos|journal=Naturwissenschaften|volume=99|issue=5|pages=369–377|bibcode=2012NW.....99..369A|doi=10.1007/s00114-012-0911-7|pmid=22528021|s2cid=2647367}}</ref> A neural spine from the holotype of ''Vallibonavenatrix'' shows a similar morphology to those of ''Ichthyovenator'', indicating the presence of a sail in this genus as well.<ref name="Elisabete Malafaia">Elisabete Malafaia; José Miguel Gasulla; Fernando Escaso; Iván Narváez; José Luis Sanz; Francisco Ortega (2019). "A new spinosaurid theropod (Dinosauria: Megalosauroidea) from the late Barremian of Vallibona, Spain: Implications for spinosaurid diversity in the Early Cretaceous of the Iberian Peninsula". Cretaceous Research. in press: 104221. {{doi|10.1016/j.cretres.2019.104221}}.</ref> One partial skeleton possibly referable to ''Angaturama'' also had elongated neural spines on its hip region.<ref>''O Estado de S. Paulo'' {{in lang|pt}}, 2009-05-14, available at [http://www.estadao.com.br/noticias/vidae,ufrj-expoe-maior-replica-de-dinossauro-carnivoro-no-pais,370960,0.htm]; ''O Globo'', 2009-05-15, abridgement available at [http://oglobo.globo.com/ciencia/mat/2009/05/14/museu-monta-replica-de-dinossauro-carnivoro-de-6-metros-no-rio-755870546.asp]; university's announcement at {{cite web |last=Moutinho |first=Sofia |date=2009-11-05 |title=Inaugura dia 14 a exposição Dinossauros no Sertão |url=http://www.ufrj.br/detalha_noticia.php?codnoticia=7486 |archive-url=https://web.archive.org/web/20110706162356/http://www.ufrj.br/detalha_noticia.php?codnoticia=7486 |archive-date=2011-07-06 |access-date=2010-01-13}}</ref><ref>{{Cite journal|last1=Machado|first1=E. B.|last2=Kellner|first2=A. W. A.|last3=Campos|first3=D. A.|date=2005|title=Preliminary information on a dinosaur (Theropoda, Spinosauridae) pelvis from the Cretaceous Santana Formation (Romualdo Member) Brazil|journal=Congresso Latino-Americano de Paleontologia de Vertebrados|volume=2 (Boletim de resumos)|pages=161–162}}</ref> The presence of a sail in fragmentary taxa like ''Sigilmassasaurus'' is unknown.<ref name="Evers-2015" /> In members of the subfamily Spinosaurinae, like ''Ichthyovenator'' and ''Spinosaurus'', the neural spines of the caudal (tail) vertebrae were tall and reclined, accompanied by also elongated chevrons—long, thin bones that form the underside of the tail. This was most pronounced in ''Spinosaurus'', in which the spines and chevrons formed a large paddle-like structure, deepening the tail significantly along most of its length.<ref>{{cite journal |last1=Ibrahim |first1=Nizar |last2=Maganuco |first2=Simone |last3=Dal Sasso |first3=Cristiano |last4=Fabbri |first4=Matteo |last5=Auditore |first5=Marco |last6=Bindellini |first6=Gabriele |last7=Martill |first7=David M. |last8=Zouhri |first8=Samir |last9=Mattarelli |first9=Diego A. |last10=Unwin |first10=David M. |last11=Wiemann |first11=Jasmina |last12=Bonadonna |first12=Davide |last13=Amane |first13=Ayoub |last14=Jakubczak |first14=Juliana |last15=Joger |first15=Ulrich |last16=Lauder |first16=George V. |last17=Pierce |first17=Stephanie E. |title=Tail-propelled aquatic locomotion in a theropod dinosaur |journal=Nature |date=7 May 2020 |volume=581 |issue=7806 |pages=67–70 |doi=10.1038/s41586-020-2190-3 |pmid=32376955 |bibcode=2020Natur.581...67I |doi-access=free }}</ref><ref name="arden2018" />

==Classification== thumb|upright=1.3|Diagram illustrating various spinosaurids

The family Spinosauridae was named by Stromer in 1915 to include the single genus ''Spinosaurus''. The clade was expanded as more close relatives of ''Spinosaurus'' were uncovered. The first cladistic definition of Spinosauridae was provided by Paul Sereno in 1998 (as "All spinosauroids closer to ''Spinosaurus'' than to ''Torvosaurus''").<ref name="Sereno Beck Dutheil et al 1998"/>

Traditionally, Spinosauridae is divided into two subfamilies: Spinosaurinae, which contains the genera ''Icthyovenator'', ''Irritator'', ''Oxalaia'', ''Sigilmassasaurus'' and ''Spinosaurus'', is marked by unserrated, straight teeth, and external nares which are further back on the skull than in baryonychines,<ref name="Sereno Beck Dutheil et al 1998"/><ref name="Rayfield20112">{{cite journal |last1=Rayfield |first1=E.J |title=Structural performance of tetanuran theropod skulls, with emphasis on the Megalosauridae, Spinosauridae and Carcharodontosauridae |journal=Special Papers in Palaeontology |date=2011 |volume=86 |pages=241–254 |oclc=769169643 }}</ref> and Baryonychinae, which contains the genera ''Baryonyx'', ''Cristatusaurus'', ''Suchosaurus'', ''Suchomimus'', ''Ceratosuchops'', and ''Riparovenator,''<ref name="BuffetautandOuaja2002" /> which is marked by serrated, slightly curved teeth, smaller size, and more teeth in the lower jaw behind the terminal rosette than in spinosaurines.<ref name="Sereno Beck Dutheil et al 1998"/><ref name="Rayfield20112"/> Others, such as ''Siamosaurus'', may belong to either Baryonychinae or Spinosaurinae, but are too incompletely known to be assigned with confidence.<ref name="BuffetautandOuaja2002" /> ''Siamosaurus'' was classified as a spinosaurine in 2018, but the results are provisional and not entirely conclusive.<ref name="arden2018"/>

The subfamily Spinosaurinae was named by Sereno in 1998, and defined by Thomas Holtz and colleagues in 2004 as all taxa closer to ''Spinosaurus aegyptiacus'' than to ''Baryonyx walkeri''. The subfamily Baryonychinae was named by Charig & Milner in 1986. They erected both the subfamily and the family Baryonychidae for the newly discovered ''Baryonyx'', before it was referred to Spinosauridae. Their subfamily was defined by Holtz and colleagues in 2004, as the complementary clade of all taxa closer to ''Baryonyx walkeri'' than to ''Spinosaurus aegyptiacus''. Examinations in 2017 by Marcos Sales and Cesar Schultz suggested that the South American spinosaurids ''Angaturama'' and ''Irritator'' may be intermediate between Baronychinae and Spinosaurinae based on their craniodental features and cladistic analysis. A study by Arden et al. 2018 named the tribe Spinosaurini to include ''Spinosaurus'' and ''Sigilmassasaurus''. The results of the 2018 phylogenetic analysis by Arden and colleagues, which included many unnamed taxa, are displayed in the cladogram below:<ref name=arden2018/>

{{clade| style=font-size: 85%; line-height:85%; |label1='''Spinosauridae''' |1={{clade |1=Praia das Aguncheiras taxon (''Iberospinus'') <div style="{{MirrorH}}">80px</div> |label2=Baryonychinae |2={{clade |1=''Baryonyx walkeri'' <div style="{{MirrorH}}">80px</div> |2=''Suchomimus tenerensis'' <div style="{{MirrorH}}">80px</div> }} |label3='''Spinosaurinae''' |3={{clade |1=''Siamosaurus suteethorni'' <div style="{{MirrorH}}">80px</div> |2={{clade |1=Eumeralla taxon<ref name="BarrettBenson2011"/> |2={{clade |1=''Ichthyovenator laosensis'' <div style="{{MirrorH}}">80px</div> |2={{clade |1=''Irritator challengeri'' <div style="{{MirrorH}}">80px</div> |2=''Oxalaia quilombensis'' <div style="{{MirrorH}}">80px</div> |label3='''Spinosaurini''' |3={{clade |1=Gara Samani taxon |2=''Sigilmassasaurus brevicollis'' <div style="{{MirrorH}}">80px</div> |3=''Spinosaurus aegyptiacus'' <div style="{{MirrorH}}">80px</div> }} }} }} }} }} }} }}

In 2021, Barker et al. described two new spinosaurid species, ''Ceratosuchops inferodios'' and ''Riparovenator milnerae'' as part of a newly proposed Ceratosuchopsini. In the paper, they performed a phylogenetic analysis focused on Spinosauridae. The results of their analysis appear below:<ref name="barkeretal2021">{{cite journal |last1=T. Barker |first1=C. |last2=Hone|first2=D. |last3=Naish|first3=D. |last4=Cau|first4=A. |last5=Lockwood|first5=J. |last6=Foster|first6=B. |last7=Clarkin|first7=C. |last8=Schneider|first8=P. |last9=Gostling|first9=N. |year=2021 |title=New spinosaurids from the Wessex Formation (Early Cretaceous, UK) and the European origins of Spinosauridae |journal=Scientific Reports |volume=11 |issue=1 |page=19340 |doi=10.1038/s41598-021-97870-8|pmid=34588472 |pmc=8481559 |bibcode=2021NatSR..1119340B }}</ref>

{{clade| style=font-size: 85%; line-height:85%; |{{clade |1=Megalosauridae middle|80px |label2='''Spinosauridae''' |2={{clade |1=''Vallibonavenatrix'' <div style="{{MirrorH}}">middle|80px</div> |2={{clade |label1=Baryonychinae |1={{clade |1={{clade |1=''Iberospinus'' <div style="{{MirrorH}}">middle|80px</div> |2=''Baryonyx'' <div style="{{MirrorH}}">middle|80px</div> }} |label2=Ceratosuchopsini |2={{clade |1=''Suchomimus'' <div style="{{MirrorH}}">middle|80px</div> |2={{clade |1=''Riparovenator'' <div style="{{MirrorH}}">middle|80px</div> |2=''Ceratosuchops'' <div style="{{MirrorH}}">middle|80px</div> }}}}}} |label2='''Spinosaurinae''' |2={{clade |1=''Camarillasaurus'' <div style="{{MirrorH}}">middle|80px</div> |2={{clade |1=''Ichthyovenator'' <div style="{{MirrorH}}">middle|80px</div> |2={{clade |1=''Irritator'' <div style="{{MirrorH}}">middle|80 px</div> |label2='''Spinosaurini''' |2={{clade |1=''Sigilmassasaurus'' <div style="{{MirrorH}}">middle|80px</div> |2={{clade |1="Spinosaurus B" |2={{clade |1=MSNM V4047 |2={{clade |1=FSAC-KK 11888 |2=''Spinosaurus'' holotype <div style="{{MirrorH}}">middle|80 px</div> }}}}}}}}}}}}}}}}}}}}}}

===Evolution=== [[File:Spinosaurid distribution in Europe and North Africa.jpg|thumb|right|alt=Map of Europe and North Africa|Distribution of spinosaurids in Europe and North Africa during the Cretaceous; 1, 3, 4, 5, 6 are ''Baryonyx'']] Spinosaurids appear to have been widespread from the Barremian to the Cenomanian stages of the Cretaceous period, about 130 to 95 million years ago. Possibly the earliest remains of spinosaurids are known from the Middle Jurassic of Niger and India, the latter of which otherwise has no remains of spinosaurids.<ref name="Sharma2023"/><ref name="JurassicTeeth">{{cite journal |last1=Serrano-Martínez |first1=A. |last2=Vidal |first2=D. |last3=Sciscio |first3=L. |last4=Ortega |first4=F. |last5=Knoll |first5=F. |date=2015 |title=Isolated theropod teeth from the Middle Jurassic of Niger and the early dental evolution of Spinosauridae |journal=Acta Palaeontologica Polonica |doi=10.4202/app.00101.2014 |s2cid=53331040 |doi-access=free |hdl-access=free |hdl=10261/152148}}</ref> They shared features such as long, narrow, crocodile-like skulls; sub-circular teeth, with fine to no serrations; the terminal rosette of the snout; and a secondary palate that made them more resistant to torsion. In contrast, the primitive and typical condition for theropods was a tall, narrow snout with blade-like (ziphodont) teeth with serrated carinae.<ref name="Holtz 1998"/> The skull adaptations of spinosaurids converged with those of crocodilians; early members of the latter group had skulls similar to typical theropods, later developing elongated snouts, conical teeth, and secondary palates. These adaptations may have been the result of a dietary change from terrestrial prey to fish. Unlike crocodiles, the post-cranial skeletons of baryonychine spinosaurids do not appear to have aquatic adaptations.<ref name="Ibrahim_et_al_2014"/><ref name="Holtz 1998">{{Cite journal|doi=10.1126/science.282.5392.1276|title=Spinosaurs as crocodile mimics|journal=Science|volume=282|issue=5392|pages=1276–1277|year=1998|last1=Holtz Jr.|first1=T. R.|bibcode=1998Sci...282.1276H |s2cid=16701711}}</ref> Sereno and colleagues proposed in 1998 that the large thumb-claw and robust forelimbs of spinosaurids evolved in the Middle Jurassic, before the elongation of the skull and other adaptations related to fish-eating, since the former features are shared with their megalosaurid relatives. They also suggested that the spinosaurines and baryonychines diverged before the Barremian age of the Early Cretaceous.<ref name="Sereno1998">{{cite journal|last=Sereno|first=P.C.|author-link=Paul Sereno|author2=Beck, A.L.|author3=Dutheil, D.B.|author4=Gado, B.|author5=Larsson, H.C.E.|author6=Lyon, G.H.|author7=Marcot, J.D.|author8=Rauhut, O.W.M.|author9=Sadleir, R.W.|author10=Sidor, C.A.|author11=Varricchio, D.D.|year=1998|title=A long-snouted predatory dinosaur from Africa and the evolution of spinosaurids|journal=Science|volume=282|issue=5392|pages=1298–1302|bibcode=1998Sci...282.1298S|doi=10.1126/science.282.5392.1298|pmid=9812890|doi-access=free|author10-link=Christian Sidor|author12=Wilson, G.P|author13=Wilson, J.A.}}</ref>

Several theories have been proposed about the biogeography of the spinosaurids. Since ''Suchomimus'' was more closely related to ''Baryonyx'' (from Europe) than to ''Spinosaurus''—although that genus also lived in Africa—the distribution of spinosaurids cannot be explained as vicariance resulting from continental rifting.<ref name=Sereno1998/> Sereno and colleagues<ref name=Sereno1998/> proposed that spinosaurids were initially distributed across the supercontinent Pangea, but split with the opening of the Tethys Sea. Spinosaurines would then have evolved in the south (Africa and South America: in Gondwana) and baryonychines in the north (Europe: in Laurasia), with ''Suchomimus'' the result of a single north-to-south dispersal event.<ref name=Sereno1998/> Buffetaut and the Tunisian palaeontologist Mohamed Ouaja also suggested in 2002 that baryonychines could be the ancestors of spinosaurines, which appear to have replaced the former in Africa.<ref>{{Cite journal | volume = 173 | pages = 415–421 | year = 2002 | doi = 10.2113/173.5.415 | last1 = Buffetaut | journal = Bulletin de la Société Géologique de France | first1 = E. | title = A new specimen of ''Spinosaurus'' (Dinosauria, Theropoda) from the Lower Cretaceous of Tunisia, with remarks on the evolutionary history of the Spinosauridae | last2 = Ouaja | first2 = M. | s2cid = 53519187 | issue = 5| bibcode = 2002BSGF..173..415B | hdl = 2042/216 | url = http://doc.rero.ch/record/14728/files/PAL_E1854.pdf }}</ref> Milner suggested in 2003 that spinosaurids originated in Laurasia during the Jurassic, and dispersed via the Iberian land bridge into Gondwana, where they radiated.<ref name="Milner 2003">{{cite journal |last=Milner |first=A. C. |year=2003 |title=Fish-eating theropods: A short review of the systematics, biology and palaeobiogeography of spinosaurs |journal=Actas de las II Jornadas Internacionales Sobre Paleontologýa de Dinosaurios y Su Entorno |pages=129–138}}</ref> In 2007, Buffetaut pointed out that palaeogeographical studies had demonstrated that Iberia was near northern Africa during the Early Cretaceous, which he found to confirm Milner's idea that the Iberian region was a stepping stone between Europe and Africa, which is supported by the presence of baryonychines in Iberia. The direction of the dispersal between Europe and Africa is still unknown,<ref name="buffetaut2007">{{cite journal |last1=Buffetaut |first1=E. |year=2007 |title=The spinosaurid dinosaur ''Baryonyx'' (Saurischia, Theropoda) in the Early Cretaceous of Portugal |journal=Geological Magazine |volume=144 |issue=6 |pages=1021–1025 |bibcode=2007GeoM..144.1021B |doi=10.1017/S0016756807003883 |s2cid=130212901|url=http://doc.rero.ch/record/13845/files/PAL_E769.pdf }}</ref> and subsequent discoveries of spinosaurid remains in Asia and possibly Australia indicate that it may have been complex.<ref name="Mateus 2011"/>

In 2016, the Spanish palaeontologist Alejandro Serrano-Martínez and colleagues reported the oldest known spinosaurid fossil, a tooth from the Middle Jurassic of Niger, which they found to suggest that spinosaurids originated in Gondwana, since other known Jurassic spinosaurid teeth are also from Africa, but they found the subsequent dispersal routes unclear.<ref name="JurassicTeeth"/> Some later studies instead suggested this tooth belonged to a megalosaurid.<ref>{{Cite journal|last1=Hendrickx|first1=Christophe|last2=Mateus|first2=O.|last3=Araújo|first3=R.|last4=Choiniere|first4=J.|date=2019|title=The distribution of dental features in non-avian theropod dinosaurs: Taxonomic potential, degree of homoplasy, and major evolutionary trends|url=https://palaeo-electronica.org/content/2019/2806-dental-features-in-theropods|journal=Palaeontologia Electronica|volume=22|issue=3|pages=1–110|doi=10.26879/820| s2cid=213164229 |issn=1094-8074|hdl=11336/146011|hdl-access=free}}</ref><ref>{{Cite journal|last1=Soto|first1=M.|last2=Toriño|first2=P.|last3=Perea|first3=D.|date=2020|title=''Ceratosaurus'' (Theropoda, Ceratosauria) teeth from the Tacuarembó Formation (Late Jurassic, Uruguay)|url=http://adsabs.harvard.edu/abs/2020JSAES.10302781S|journal=Journal of South American Earth Sciences|volume=103|article-number=102781|doi=10.1016/j.jsames.2020.102781|bibcode=2020JSAES.10302781S|s2cid=224842133|issn=0895-9811}}</ref> Candeiro and colleagues suggested in 2017 that spinosaurids of northern Gondwana were replaced by other predators, such as abelisauroids, since no definite spinosaurid fossils are known from after the Cenomanian anywhere in the world. They attributed the disappearance of spinosaurids and other shifts in the fauna of Gondwana to changes in the environment, perhaps caused by transgressions in sea level.<ref name="Biogeography">{{cite journal|last1=Candeiro|first1=C. R. A.|last2=Brusatte|first2=S. L.|last3=Souza|first3=A. L.|title=Spinosaurid Dinosaurs from the Early Cretaceous of North Africa and Europe: Fossil Record, Biogeography and Extinction|journal=Anuário do Instituto de Geociências|date=2017|volume=40|issue=3|pages=294–302|doi=10.11137/2017_3_294_302|doi-access=free|hdl=20.500.11820/1bc143b5-5bd5-416b-bf10-dd28304d2c9b|hdl-access=free}}</ref> Malafaia and colleagues stated in 2020 that ''Baryonyx'' remains the oldest unquestionable spinosaurid, while acknowledging that older remains had also been tentatively assigned to the group.<ref name="Malafaia2020">{{cite journal |last1=Malafaia |first1=E. |last2=Gasulla |first2=J. M. |last3=Escaso |first3=F. |last4=Narvaéz |first4=I. |last5=Ortega |first5=F. |title=An update of the spinosaurid (Dinosauria: Theropoda) fossil record from the Lower Cretaceous of the Iberian Peninsula: distribution, diversity, and evolutionary history |journal=Journal of Iberian Geology |date=2020 |volume=46 |issue=4 |pages=431–444 |doi=10.1007/s41513-020-00138-9|bibcode=2020JIbG...46..431M |s2cid=222149842 |hdl=20.500.14468/31927 |hdl-access=free }}</ref> Barker and colleagues found support for a European origin for spinosaurids in 2021, with an expansion to Asia and Gondwana during the first half of the Early Cretaceous. In contrast to Sereno, these authors suggested there had been at least two dispersal events from Europe to Africa, leading to ''Suchomimus'' and the African part of Spinosaurinae.<ref name="NewSpinosaurids">{{cite journal |last1=Barker |first1=C. T. |last2=Hone |first2=D. W. E. |last3=Naish |first3=D. |last4=Cau |first4=A. |last5=Lockwood |first5=J. A. F. |last6=Foster |first6=B. |last7=Clarkin |first7=C. E. |last8=Schneider |first8=P. |last9=Gostling |first9=N. J. |title=New spinosaurids from the Wessex Formation (Early Cretaceous, UK) and the European origins of Spinosauridae |journal=Scientific Reports |date=2021 |volume=11 |issue=1 |page=19340 | pmid=34588472| doi=10.1038/s41598-021-97870-8|pmc=8481559|bibcode=2021NatSR..1119340B }}</ref>

==Paleobiology==

===Diet and feeding=== [[File:Comparative_evolution_of_jaws_between_Muraenesocidae_(A)_and_Spinosauridae_(B).png|thumb|right|Comparison of a spinosaurid skull with that of ''Dubreuillosaurus'' and two extant pike conger eels]]

Spinosaurid teeth resemble those of crocodiles, which are used for piercing and holding prey. Therefore, teeth with small or no serrations, such as in spinosaurids, were not good for cutting or ripping into flesh but instead helped to ensure a strong grip on a struggling prey animal.<ref name="suesetal20022">{{cite journal |last1=Sues |first1=Hans-Dieter |last2=Frey |first2=Eberhard |last3=Martill |first3=David M. |last4=Scott |first4=Diane M. |title=Irritator challengeri , a spinosaurid (Dinosauria: Theropoda) from the Lower Cretaceous of Brazil |journal=Journal of Vertebrate Paleontology |date=19 September 2002 |volume=22 |issue=3 |pages=535–547 |doi=10.1671/0272-4634(2002)022[0535:ICASDT]2.0.CO;2 |s2cid=131050889 }}</ref> However, some have argued that spinosaurids converge more with phytosaurs in terms of craniodental anatomy and that phytosaurs are a better analogue for inferring their life modes.<ref>{{Cite journal |last1=Yun |first1=Chan-Gyu |date=23 December 2023 |title=SPINOSAURS AS PHYTOSAUR MIMICS: A CASE OF CONVERGENT EVOLUTION BETWEEN TWO EXTINCT ARCHOSAURIFORM CLADES |url=https://www.researchgate.net/profile/Changyu-Yun/publication/373816152_Spinosaurs_as_phytosaur_mimics_a_case_of_convergent_evolution_between_two_extinct_archosauriform_clades/links/64fe89d9849bbb203b8edb15/Spinosaurs-as-phytosaur-mimics-a-case-of-convergent-evolution-between-two-extinct-archosauriform-clades.pdf |journal=Acta Palaeontologica Romaniae |language=en |issue=20 (1) |pages=17–29 |doi=10.35463/j.apr.2024.01.02 |issn=1842-371X |access-date=8 February 2026 |via=ResearchGate}}</ref> Spinosaurid jaws were likened by Romain Vullo and colleagues to those of the pike conger eel, in what they hypothesized was convergent evolution for aquatic feeding. Both kinds of animals have some teeth in the end of the upper and lower jaws that are larger than the others and an area of the upper jaw with smaller teeth, creating a gap into which the enlarged teeth of the lower jaw fit, with the full structure called a terminal rosette.<ref name="Vulloetal.2016">{{cite journal |last1=Vullo |first1=Romain |last2=Allain |first2=Ronan |last3=Cavin |first3=Lionel |date=2016 |title=Convergent evolution of jaws between spinosaurid dinosaurs and pike conger eels |journal=Acta Palaeontologica Polonica |volume=61 |issue=4 |page=825 |doi=10.4202/app.00284.2016 |doi-access=free |bibcode=2016AcPaP..61..825V }}</ref> alt=|left|thumb|Life restoration of ''Baryonyx'' with a fish in its jaws In the past, spinosaurids have often been considered piscivores (fish-eaters) in the main, based on comparisons of their jaws with those of modern crocodilians.<ref name="Rayfield20112"/> In 2007, British paleontologist Emily J. Rayfield and colleagues conducted biomechanical studies on the skull of ''Baryonyx'', which had a long, laterally compressed skull, comparing it to gharial (long, narrow, tubular) and alligator (flat and wide) skulls. They found that the structure of baryonychine jaws converged on that of gharials, in that the two taxa showed similar response patterns to stress from simulated feeding loads, and did so with and without the presence of a (simulated) secondary palate. The gharial, exemplar of a long, narrow, and tubular snout, is a fish specialist. However, this snout anatomy does not preclude other options for the spinosaurids. The gharial is the most extreme example and a fish specialist; Australian freshwater crocodiles, which have similarly shaped skulls to gharials, also specialize more on fish than sympatric, broad snouted crocodiles and are opportunistic feeders which eat all manner of small aquatic prey, including insects and crustaceans. Thus, spinosaurids' snouts correlate with piscivory; this is consistent with hypotheses of this diet for spinosaurids, in particular baryonychines, but it does not indicate that they were solely piscivorous.<ref name="rayfieldetal2007"/> thumb|right|Life restoration of the head of ''Spinosaurus'' Further study by Andrew R. Cuff and Rayfield in 2013 on the skulls of ''Spinosaurus'' and ''Baryonyx'' did not recover similarities in the skulls of ''Baryonyx'' and the gharial that the previous study did. ''Baryonyx'' had, in models where the size difference of the skulls was corrected for, greater resistance to torsion and dorsoventral bending than both ''Spinosaurus'' and the gharial, while both spinosaurids were inferior to the gharial, alligator, and slender-snouted crocodile in resisting torsion and medio-lateral bending. When the results from the modeling were not scaled according to size, then both spinosaurids performed better than all the crocodilians in resistance to bending and torsion, due to their larger size. Thus, Cuff and Rayfield suggested that the skulls were not efficiently built to deal well with relatively large, struggling prey, but that spinosaurids may overcome prey simply by their size advantage, and not skull build.<ref name="CuffandRayfield2013">{{cite journal |last1=Cuff |first1=Andrew R. |last2=Rayfield |first2=Emily J. |title=Feeding Mechanics in Spinosaurid Theropods and Extant Crocodilians |journal=PLOS ONE |date=28 May 2013 |volume=8 |issue=5 |article-number=e65295 |doi=10.1371/journal.pone.0065295 |pmid=23724135 |pmc=3665537 |bibcode=2013PLoSO...865295C |doi-access=free }}</ref> In 2002, Hans-Dieter Sues and colleagues studied the construction of the spinosaurid skull, and concluded that their mode of feeding was to use extremely quick, powerful strikes to seize small prey items using their jaws, whilst employing the powerful neck muscles in rapid up-and-down motion. Due to the narrow snout, vigorous side-to-side motion of the skull during prey capture is unlikely.<ref name="suesetal20022"/> Based on the size and positions of their nostrils, Marcos Sales and Cesar Schultz in 2017 suggested that ''Spinosaurus'' possessed a greater reliance on its sense of smell and had a more piscivorous lifestyle than ''Irritator'' and baryonychines.<ref name="salesschultz">{{cite journal|first1=M.A.F. |last1=Sales |first2=C.L. |last2=Schultz |year=2017 |title=Spinosaur taxonomy and evolution of craniodental features: Evidence from Brazil |journal=PLOS ONE |volume=12 |issue=11 |article-number=e0187070 |doi=10.1371/journal.pone.0187070 |pmid=29107966 |pmc=5673194 |bibcode=2017PLoSO..1287070S |doi-access=free }}</ref>

[[File:20130825_Brazil_Rio_de_Janeiro_0144.jpg|thumb|left|alt=Reconstructed skeleton holding a pterosaur in its jaws against a painted backdrop|Reconstructed ''Irritator'' skeleton mounted as attacking an anhanguerid pterosaur, National Museum of Rio de Janeiro]]

Direct fossil evidence shows that spinosaurids fed on fish as well as a variety of other small to medium-sized animals, including dinosaurs. ''Baryonyx'' was found with scales of the prehistoric fish ''Scheenstia'' in its body cavity, and these were abraded, hypothetically by gastric juices. Bones of a young ''Iguanodon'', also abraded, were found alongside this specimen. If these represent ''Baryonyx''<nowiki/>'s meal, the animal was, whether in this case a hunter, or a scavenger, an eater of more diverse fare than fish.<ref name="Rayfield20112" /><ref name="suesetal20022" /><ref name="charigmilner19973" /> Moreover, there is a documented example of a spinosaurid having eaten a pterosaur, as one ''Irritator'' tooth was found lodged within the fossil vertebrae of an ornithocheirid pterosaur found in the Romualdo Formation of Brazil. This may represent a predation or a scavenging event.<ref>{{cite journal |last1=Witton |first1=Mark P. |title=Pterosaurs in Mesozoic food webs: a review of fossil evidence |journal=Geological Society, London, Special Publications |date=2018 |volume=455 |issue=1 |pages=7–23 |doi=10.1144/SP455.3 |bibcode=2018GSLSP.455....7W |s2cid=90573936 }}</ref><ref name="Buffetautetal.20042">{{cite journal |last1=Buffetaut |first1=Eric |last2=Martill |first2=David |last3=Escuillié |first3=François |title=Pterosaurs as part of a spinosaur diet |journal=Nature |date=July 2004 |volume=430 |issue=6995 |page=33 |doi=10.1038/430033a |pmid=15229562 |bibcode=2004Natur.429...33B |s2cid=4398855 |doi-access=free }}</ref> A fossil snout referred to ''Spinosaurus'' was discovered with a vertebra from the sclerorhynchid ''Onchopristis'' embedded in it.<ref name="Sasso Maganuco Buffetaut Mendez 2005"/> In the Sao Khua Formation of Thailand, isolated tooth crowns from ''Siamosaurus'' have been found in association with sauropod remains, indicating possible predation or scavenging.<ref>{{cite journal |last1=Buffetaut |first1=Eric |last2=Suteethorn |first2=Varavudh |title=The dinosaur fauna of the Sao Khua Formation of Thailand and the beginning of the Cretaceous radiation of dinosaurs in Asia |journal=Palaeogeography, Palaeoclimatology, Palaeoecology |date=June 1999 |volume=150 |issue=1–2 |pages=13–23 |doi=10.1016/S0031-0182(99)00004-8 |bibcode=1999PPP...150...13B |url=http://doc.rero.ch/record/14471/files/PAL_E1664.pdf }}</ref> The Portuguese ''Iberospinus'' fossils were also found associated with isolated Iguanodon teeth, and those cases are listed; along with other such associations as support for opportunistic feeding behaviour in spinosaurids.<ref>{{cite journal | pmc=4703214 | date=2016 | last1=Hendrickx | first1=C. | last2=Mateus | first2=O. | last3=Buffetaut | first3=E. | title=Morphofunctional Analysis of the Quadrate of Spinosauridae (Dinosauria: Theropoda) and the Presence of Spinosaurus and a Second Spinosaurine Taxon in the Cenomanian of North Africa | journal=PLOS ONE | volume=11 | issue=1 | article-number=e0144695 | doi=10.1371/journal.pone.0144695 | pmid=26734729 | bibcode=2016PLoSO..1144695H | doi-access=free }}</ref>

A 2018 study by Auguste Hassler and colleagues of calcium isotopes in the teeth of North African theropods found that spinosaurids had a mixed diet of fish and herbivorous dinosaurs, whereas the other theropods examined (abelisaurids and carcharodontosaurids) mainly fed on herbivorous dinosaurs. This might indicate ecological partitioning between these theropods.<ref name="Calciumisotopes">{{cite journal |last1=Hassler |first1=A. |last2=Martin |first2=J. E. |last3=Amiot |first3=R. |last4=Tacail |first4=T. |last5=Godet |first5=F. Arnaud |last6=Allain |first6=R. |last7=Balter |first7=V. |title=Calcium isotopes offer clues on resource partitioning among Cretaceous predatory dinosaurs |journal=Proceedings of the Royal Society B: Biological Sciences |date=11 April 2018 |volume=285 |issue=1876 |article-number=20180197 |doi=10.1098/rspb.2018.0197 |pmid=29643213 |pmc=5904318 }}</ref> Later in 2018, Tito Aureliano and colleagues presented a possible scenario for the food web of Brazilian Romualdo Formation. The researchers proposed that the diet of spinosaurines from this environment may have included—in addition to pterosaurs—terrestrial and aquatic crocodyliforms, juveniles of their own species, turtles, and small to medium-sized dinosaurs. This would have made spinosaurines apex predators within this particular ecosystem.<ref name="Aureliano Ghilardi Buck et al 2018"/>

A 2024 study by D'Amore et al., further vindicates the theory that spinosaurids were similar in niche to generalist or macro-generalist crocodilians. This study likewise suggests their jaws and teeth were well-suited to quick strikes and deep, puncturing bites, but not for slicing flesh or crushing bones. In particular, baryonychine spinosaurids probably did little oral processing of their prey when feeding, but by comparison, spinosaurines were found to be quite capable of processing the meat of relatively large vertebrate prey. None of these findings suggest any spinosaurids from either subfamily were restricted only to fish and small aquatic vertebrates.<ref>{{Cite journal |last1=D'Amore |first1=Domenic C. |last2=Johnson-Ransom |first2=Evan |last3=Snively |first3=Eric |last4=Hone |first4=David W. E. |date=2024-08-28 |title=Prey size and ecological separation in spinosaurid theropods based on heterodonty and rostrum shape |url=https://anatomypubs.onlinelibrary.wiley.com/doi/10.1002/ar.25563 |journal=The Anatomical Record |volume=308 |issue=5 |pages=1331–1348 |language=en |doi=10.1002/ar.25563 |pmid=39205383 |issn=1932-8486|url-access=subscription }}</ref>

=== Forelimb function === [[File:Suchomimus_arm_Museum_of_Anchient_Life.jpg|thumb|Reconstructed forelimb and hand of ''Suchomimus'', Museum of Ancient Life, Utah]]

The use of the robust forelimbs and giant recurved claws of spinosaurs remains a debated topic. Charig and Milner speculated in 1986 that ''Baryonyx'' may have crouched by the riverbank and used its claws to gaff fish out of the water, similarly to grizzly bears.<ref name="Charig Milner 1986">{{cite journal|last1=Charig|first1=A. J.|last2=Milner|first2=A. C.|year=1986|title=''Baryonyx'', a remarkable new theropod dinosaur|journal=Nature|volume=324|issue=6095|pages=359–361|bibcode=1986Natur.324..359C|doi=10.1038/324359a0|pmid=3785404|s2cid=4343514}}</ref> In 1987, British biologist Andrew Kitchener argued that with both its crocodile-like snout and enlarged claws, ''Baryonyx'' seemed to have too many adaptations for piscivory when one would have been enough. Kitchener instead postulated that ''Baryonyx'' more likely used its arms to scavenge the corpses of large dinosaurs, such as ''Iguanodon'', by breaking into the carcass with the large claws, and subsequently probing for viscera with its long snout.<ref>{{cite journal |last1=Kitchener |first1=Andrew |title=Function of Claws' claws |journal=Nature |date=January 1987 |volume=325 |issue=6100 |page=114 |doi=10.1038/325114a0 |bibcode=1987Natur.325..114K |s2cid=4264665 }}</ref> In their 1997 article, Charig and Milner rejected this hypothesis, pointing out that in most cases, a carcass would have already been largely emptied out by its initial predators.<ref name="charigmilner19973" /> Later research has also ruled out this sort of specialized scavenging.<ref name=Hone2017/>

In 1986, Charig and Milner suggested that the robust forelimbs and giant thumb claws would have been ''Baryonyx''<nowiki/>'s primary method of capturing, killing, and tearing apart large prey; whereas its long snout would have been used mostly for fishing.<ref name="charigmilner19973" /> A 2005 study by Canadian paleontologist the François Therrien and colleagues agreed that spinosaur forelimbs were probably used for hunting larger prey items, given that their snouts could not resist the bending stress.<ref name="therrien2005">{{cite book|title=The Carnivorous Dinosaurs|last1=Therrien|first1=F.|last2=Henderson|first2=D.|last3=Ruff|first3=C.|publisher=Indiana University Press|year=2005|isbn=978-0-253-34539-4|editor-last=Carpenter|editor-first=K.|pages=179–230|chapter=Bite me – biomechanical models of theropod mandibles and implications for feeding behavior}}</ref> In a 2017 review of the family, David Hone and Holtz considered possible functions in digging for water sources or hard to reach prey, as well as burrowing into soil to construct nests.<ref name=Hone2017/>

=== Cranial crests and neural spines === [[File:Irritator_and_Angaturama_skulls.png|thumb|alt=Head silhouettes of Irritator and Angaturama with respective skull bones overlaid onto them, the ''Angaturama'' specimen is larger and overlaps with that of ''Irritator'' by one tooth|Holotype skull specimens of ''Irritator challengeri'' (top, showing the beginnings of a nasal crest) and ''Angaturama limai'' (bottom, showing a tall premaxillary crest)]]

Theropod heads are often decorated with some form of crest, horn, or rugose structure, which in life, would have been extended by keratin.<ref name="Carpenter-2005">{{Cite book|title=The Carnivorous Dinosaurs|last=Carpenter|first=Kenneth|publisher=Indiana University Press|year=2005|isbn=978-0-253-34539-4|pages=285–291}}</ref> Though there has been little discussion on the head crests of spinosaurs, Hone and Holtz in 2017 considered that their most likely use was for displaying to potential mates or as a means of threatening rivals and other predators.<ref name=Hone2017/> Such has been suggested for theropod cranial structures before, which may have been aided by unusual or bright coloration to provide further visual cues.<ref name="Carpenter-2005" />

Many theories have been proposed over the years for the use of spinosaurid dorsal sails, such as thermoregulation;<ref name="LBH75">{{cite book|title=The Evolution and Ecology of the Dinosaurs|last=Halstead|first=L.B.|publisher=Eurobook Limited|year=1975|isbn=978-0-85654-018-9|location=London|pages=1–116|author-link=Beverly Halstead}}</ref> to aid in swimming;<ref>{{cite journal |last1=Gimsa |first1=Jan |last2=Sleigh |first2=Robert |last3=Gimsa |first3=Ulrike |title=The riddle of Spinosaurus aegyptiacus' dorsal sail |journal=Geological Magazine |date=May 2016 |volume=153 |issue=3 |pages=544–547 |doi=10.1017/S0016756815000801 |bibcode=2016GeoM..153..544G |s2cid=51999370 |url=https://repository.publisso.de/resource/frl:6402283/data |doi-access=free }}</ref> to store energy or insulate the animal; or for display purposes, such as intimidating rivals and predators, or attracting mates.<ref name="JBB972">{{cite journal|last=Bailey|first=J.B.|year=1997|title=Neural spine elongation in dinosaurs: sailbacks or buffalo-backs?|journal=Journal of Paleontology|volume=71|issue=6|pages=1124–1146|jstor=1306608|doi=10.1017/S0022336000036076|bibcode=1997JPal...71.1124B |s2cid=130861276 }}</ref><ref name="Stromer15">{{cite journal|last=Stromer|first=E.|author-link=Ernst Stromer|year=1915|title=Ergebnisse der Forschungsreisen Prof. E. Stromers in den Wüsten Ägyptens. II. Wirbeltier-Reste der Baharije-Stufe (unterstes Cenoman). 3. Das Original des Theropoden ''Spinosaurus aegyptiacus'' nov. gen., nov. spec|url=http://www.megaupload.com/?d=3KCCC7LS|journal=Abhandlungen der Königlich Bayerischen Akademie der Wissenschaften, Mathematisch-physikalische Klasse|language=de|volume=28|issue=3|pages=1–32}}{{dead link|date=December 2017|bot=InternetArchiveBot|fix-attempted=yes}}</ref> Many elaborate body structures of modern-day animals serve to attract members of the opposite sex during mating. It is possible that the sail of ''Spinosaurus'' was used for courtship, in a way similar to a peacock's tail. In 1915, Stromer speculated that the size of the neural spines may have differed between males and females.<ref name="Stromer15"/> In 2012, French paleontologist Ronan Allain and colleagues suggested considering the high diversity in neural spine elongation observed in theropod dinosaurs, as well as histological research done on the sails of synapsids (stem mammals), the sinusoidal sail of ''Ichthyovenator'' was likely used for courtship display or recognising members of its own species.<ref name="AXRK12">{{Cite journal|last1=Allain|first1=Ronan|last2=Xaisanavong|first2=Tiengkham|last3=Richir|first3=Philippe|last4=Khentavong|first4=Bounsou|year=2012|title=The first definitive Asian spinosaurid (Dinosauria: Theropoda) from the early cretaceous of Laos|journal=Naturwissenschaften|volume=99|issue=5|pages=369–377|bibcode=2012NW.....99..369A|doi=10.1007/s00114-012-0911-7|pmid=22528021|s2cid=2647367}}</ref> In a 2013 blog post, Darren Naish considered the latter function unlikely, favouring the hypothesis of sexual selection for ''Ichthyovenator''{{'}}s sail because it appears to have evolved on its own, without very close relatives. Naish also notes it is possible similar relatives have not yet been discovered.<ref>{{Cite web|title=Dinosaurs and their exaggerated structures: species recognition aids, or sexual display devices?|url=https://blogs.scientificamerican.com/tetrapod-zoology/species-recognition-vs-sexual-selection-in-dinosaurs/|last=Naish|first=Darren|date=2013|website=Scientific American Blog Network|language=en|access-date=2020-04-09}}</ref>

In 2015, the German biophysicist Jan Gimsa and colleagues suggested that this feature could also have aided aquatic movement by improving manoeuvrability when submerged, and acted as fulcrum for powerful movements of the neck and tail (similar to those of sailfish or thresher sharks).<ref name="Riddle">{{cite journal |last1=Gimsa |first1=J. |last2=Sleigh |first2=R. |last3=Gimsa |first3=U. |title=The riddle of ''Spinosaurus aegyptiacus'' dorsal sail |journal=Geological Magazine |date=2015 |volume=153 |issue=3 |pages=544–547 |doi=10.1017/S0016756815000801|bibcode=2016GeoM..153..544G |s2cid=51999370 |doi-access=free }}</ref><ref>{{cite journal |last1=Bailey |first1=J. B. |title=Neural spine elongation in dinosaurs: sailbacks or buffalo-backs? |journal=Journal of Paleontology |date=2015 |volume=71 |issue=6 |pages=1124–1146 |doi=10.1017/S0022336000036076|bibcode=1997JPal...71.1124B |s2cid=130861276 }}</ref>

===Ontogeny===

Juvenile spinosaurid fossils are somewhat rare. However, an ungual phalanx measuring {{convert|21|mm|in|abbr=on}} belonging to a very young ''Spinosaurus'' indicates that ''Spinosaurus,'' and probably by extent other spinosaurids, may have developed their semiaquatic adaptations at birth or at a very young age and maintained the adaptations throughout their lives. The specimen, found in 1999 and described by Simone Maganuco, Cristiano Dal Sasso and colleagues in 2018, is believed to have come from a very small juvenile measuring {{convert|1.78|m|ft|abbr=on}}, making said specimen the smallest known example of a spinosaurid currently described.<ref>{{cite press release |publisher=PeerJ |title=The smallest biggest theropod dinosaur: A new fossil from Africa represents a small juvenile individual of the huge sail-backed Spinosaurus |url=https://www.sciencedaily.com/releases/2018/05/180530132947.htm |date=30 May 2018 }}</ref><ref>{{cite news |last1=Anderson |first1=Natali |title=Paleontologists Find Fossil of Smallest Spinosaurus |url=http://www.sci-news.com/paleontology/smallest-spinosaurus-06052.html |work=Sci-News.com |date=31 May 2018 }}</ref>

== Paleoecology ==

=== Habitat preference === A 2010 publication by Romain Amiot and colleagues found that oxygen isotope ratios of spinosaurid bones indicates semiaquatic lifestyles. Isotope ratios from teeth from ''Baryonyx'', ''Irritator'', ''Siamosaurus'', and ''Spinosaurus'' were compared with isotopic compositions from contemporaneous theropods, turtles, and crocodilians. The study found that, among theropods, spinosaurid isotope ratios were closer to those of turtles and crocodilians. ''Siamosaurus'' specimens tended to have the largest difference from the ratios of other theropods, and ''Spinosaurus'' tended to have the least difference. The authors concluded that spinosaurids, like modern crocodilians and hippopotamuses, spent much of their daily lives in water. The authors also suggested that semiaquatic habits and piscivory in spinosaurids can explain how spinosaurids coexisted with other large theropods: by feeding on different prey items and living in different habitats, the different types of theropods would have been out of direct competition.<ref name="RMetal10">{{cite journal|last1=Amiot|first1=R.|last2=Buffetaut|first2=E.|last3=Lécuyer|first3=C.|last4=Wang|first4=X.|last5=Boudad|first5=L.|last6=Ding|first6=Z.|last7=Fourel|first7=F.|last8=Hutt|first8=S.|last9=Martineau|first9=F.|last10=Medeiros|first10=A.|last11=Mo|first11=J.|year=2010|title=Oxygen isotope evidence for semi-aquatic habits among spinosaurid theropods|journal=Geology|volume=38|issue=2|pages=139–142|bibcode=2010Geo....38..139A|doi=10.1130/G30402.1|last12=Simon|first12=L.|last13=Suteethorn|first13=V.|last14=Sweetman|first14=S.|last15=Tong|first15=H.|last16=Zhang|first16=F.|last17=Zhou|first17=Z.}}</ref> In 2018, an analysis was conducted on the partial tibia of an indeterminate spinosaurine from the early Albian, the bone was from a sub-adult between 7 and 13 m (22 and 42 ft) in length still growing moderately fast before its death. This specimen (LPP-PV-0042) was found in the Araripe Basin of Brazil and taken to the University of San Carlos for a CT Scan, where it revealed osteosclerosis (high bone density).<ref name="Aureliano Ghilardi Buck et al 2018"/> This condition had previously only been observed in ''Spinosaurus,'' as a possible way of controlling its buoyancy.<ref name="Spinosaurus 2014" /> The presence of this condition on the leg fragment showed that semi-aquatic adaptations in spinosaurids were already present at least 10 million years before ''Spinosaurus aegyptiacus'' appeared. According to the phylogenetic bracketing method, this high bone density might have been present in all spinosaurines.<ref name="Aureliano Ghilardi Buck et al 2018"/> In 2020, a scientific paper by paleontologists published in the scientific journal Cretaceous Research found taphonomic evidence in the Kem Kem group that would support ''Spinosaurus'' being a semi-aquatic dinosaur.<ref>{{cite journal |last1=Beevor |first1=Thomas |last2=Quigley |first2=Aaron |last3=Smith |first3=Roy E. |last4=Smyth |first4=Robert S.H. |last5=Ibrahim |first5=Nizar |last6=Zouhri |first6=Samir |last7=Martill |first7=David M. |title=Taphonomic evidence supports an aquatic lifestyle for Spinosaurus |journal=Cretaceous Research |date=January 2021 |volume=117 |article-number=104627 |doi=10.1016/j.cretres.2020.104627 |bibcode=2021CrRes.11704627B |s2cid=224888268 |url=https://researchportal.port.ac.uk/portal/en/publications/taphonomic-evidence-supports-an-aquatic-lifestyle-for-spinosaurus(e7fb2358-2ac6-4b6c-9697-225a525e8366).html }}</ref> However, research conducted in 2024 by Myhrvold and colleagues cited the immediate assumption of spinosaurids being avid divers due to correlations in bone compactness as being subject to errors, such as flawed statistical methods and measurements, as well as sampling bias. Given the amount of variation in specimens and in data collection techniques, they concluded that previous evidence isn't strong enough to put ''Spinosaurus'' swimming and diving entirely submerged, suggesting that ''Spinosaurus'' still more likely mostly hung out on shore, akin to wader lifestyle previously interfered.<ref>{{cite journal | doi=10.1371/journal.pone.0298957 | doi-access=free | title=Diving dinosaurs? Caveats on the use of bone compactness and pFDA for inferring lifestyle | date=2024 | last1=Myhrvold | first1=Nathan P. | last2=Baumgart | first2=Stephanie L. | last3=Vidal | first3=Daniel | last4=Fish | first4=Frank E. | last5=Henderson | first5=Donald M. | last6=Saitta | first6=Evan T. | last7=Sereno | first7=Paul C. | journal=PLOS ONE | volume=19 | issue=3 | article-number=e0298957 | pmid=38446841 | pmc=10917332 | bibcode=2024PLoSO..1998957M }}</ref>

A 2018 study of buoyancy (through simulation with 3D models) by the Canadian palaeontologist Donald M. Henderson found that distantly related theropods floated as well as the tested spinosaurs, and instead supported they would have stayed by the shorelines or shallow water rather than being semi-aquatic.<ref name="Henderson">{{cite journal|last1=Henderson|first1=D. M.|date=2018|title=A buoyancy, balance and stability challenge to the hypothesis of a semi-aquatic ''Spinosaurus'' Stromer, 1915 (Dinosauria: Theropoda)|journal=PeerJ|volume=6|article-number=e5409|doi=10.7717/peerj.5409|pmc=6098948|pmid=30128195 |doi-access=free }}</ref>

A 2026 paper by Cau ''et al.'' analyzed five Spinosaurine skulls and found evidence of the presence of salt glands, which had convergently evolved to be similar to the salt glands of semi-aquatic and aquatic birds. Which shows that derived Spinosaurines were able to hunt in brackish and saltwater environments. The research concludes that the presence of the salt glands in the Spinosaurinae is compatible with either ecological model discussed for that clade. <ref>{{Cite journal |last=Cau |first=Andrea |last2=Gostling |first2=Neil J. |last3=Lacerda |first3=Mauro B. S. |last4=Falasca |first4=Mario |last5=Paterna |first5=Alessandro |date=2026-05-22 |title=Avian-like salt glands in Spinosauridae |url=https://www.tandfonline.com/doi/full/10.1080/08912963.2026.2669954 |journal=Historical Biology |language=en |pages=1–13 |doi=10.1080/08912963.2026.2669954 |issn=0891-2963}}</ref>

=== Distribution === [[File:Palaeogeographic locations of spinosaurids (white) and the specimen of HB site (black), through time from Bajocian–Bathonian (A), Tithonian (B), Barremian−Aptian (C), and Albian−Cenomanian (D).jpg|alt=|thumb|upright=1.3|Generalized locations of spinosaurid fossil discoveries from the Bajocian–Bathonian (A), Tithonian (B), Barremian−Aptian (C), and Albian−Cenomanian (D) marked on maps of those time spans.]] Confirmed spinosaurids have been found on every continent except for North America, Australia and Antarctica, the first of which was ''Spinosaurus aegyptiacus'', discovered at the Bahariya Formation in Egypt.<ref name="Stromer15" /> Baryonychines were common, such as ''Baryonyx'', which lived during the Barremian of England and Spain. ''Baryonyx''-like teeth are also found from the earlier Hauterivian and later Aptian sediments of Spain, as well as the Hauterivian of England.<ref name=Hone2017/><ref name="Mateus 2011">{{cite journal|last1=Mateus|first1=O.|last2=Araújo|first2=R.|last3=Natário|first3=C.|last4=Castanhinha|first4=R.|year=2011|title=A new specimen of the theropod dinosaur ''Baryonyx'' from the early Cretaceous of Portugal and taxonomic validity of ''Suchosaurus''|url=http://docentes.fct.unl.pt/sites/default/files/omateus/files/mateus_et_al_2011_a_new_specimen_of_the_theropod_dinosaur_baryonyx_from_the_early_cretaceous_of_portugal_and_taxonomic_validity_of_suchosaurus.pdf|journal=Zootaxa|series=2827|volume=2827|pages=54–68|doi=10.11646/zootaxa.2827.1.3 |bibcode=2011Zoot.28277.1.3M }}</ref> Baryonychines were represented in Africa, with ''Suchomimus'' ''tenerensis'' and ''Cristatusaurus lapparenti'' as well as ''Baryonyx''-like teeth from the Aptian of Niger.<ref name="BuffetautandOuaja2002" /><ref name="Sereno Beck Dutheil et al 1998">{{cite journal |last1=Sereno |first1=Paul C. |last2=Beck |first2=Allison L. |last3=Dutheil |first3=Didier B. |last4=Gado |first4=Boubacar |last5=Larsson |first5=Hans C. E. |last6=Lyon |first6=Gabrielle H. |last7=Marcot |first7=Jonathan D. |last8=Rauhut |first8=Oliver W. M. |last9=Sadleir |first9=Rudyard W. |last10=Sidor |first10=Christian A. |last11=Varricchio |first11=David D. |last12=Wilson |first12=Gregory P. |last13=Wilson |first13=Jeffrey A. |title=A Long-Snouted Predatory Dinosaur from Africa and the Evolution of Spinosaurids |journal=Science |date=13 November 1998 |volume=282 |issue=5392 |pages=1298–1302 |doi=10.1126/science.282.5392.1298 |pmid=9812890 |bibcode=1998Sci...282.1298S |citeseerx=10.1.1.502.3887 }}</ref><ref name="TaquetRussell">{{cite journal |last1=Taquet |first1=Philippe |last2=Russell |first2=Dale A. |title=New data on spinosaurid dinosaurs from the early cretaceous of the Sahara |journal=Comptes Rendus de l'Académie des Sciences - Series IIA - Earth and Planetary Science |date=September 1998 |volume=327 |issue=5 |pages=347–353 |doi=10.1016/S1251-8050(98)80054-2 |bibcode=1998CRASE.327..347T }}</ref> as well as in Europe, with ''Suchosaurus cultridens'' and ''S. girardi'' from the England. ''Baryonyx-''like teeth are also reported from the Ashdown Sands of Sussex, in England, and the Burgos Province, in Spain.<ref name="Mateus 2011" /> Other European spinosaurids ''Camarillasaurus cirugedae'' and ''Iberospinus natarioi'' are known from the Barremian of Spain and Portugal, respectively.<ref>{{cite journal |last1=Samathi |first1=Adun |last2=Sander |first2=P. Martin |last3=Chanthasit |first3=Phornphen |title=A spinosaurid from Thailand (Sao Khua Formation, Early Cretaceous) and a reassessment of Camarillasaurus cirugedae from the Early Cretaceous of Spain |journal=Historical Biology |date=2 December 2021 |volume=33 |issue=12 |pages=3480–3494 |doi=10.1080/08912963.2021.1874372 |bibcode=2021HBio...33.3480S |s2cid=233884025 }}</ref><ref name="Mateus & Estraviz-López 2022">{{cite journal |last1=Mateus |first1=Octávio |last2=Estraviz-López |first2=Darío |title=A new theropod dinosaur from the early cretaceous (Barremian) of Cabo Espichel, Portugal: Implications for spinosaurid evolution |journal=PLOS ONE |date=16 February 2022 |volume=17 |issue=2 |article-number=e0262614 |doi=10.1371/journal.pone.0262614 |pmid=35171930 |pmc=8849621 |bibcode=2022PLoSO..1762614M |doi-access=free }}</ref>

The earliest record of spinosaurines is from Europe, with the Barremian species ''Vallibonavenatrix cani'' from Spain.<ref name="Elisabete Malafaia" /> Spinosaurines are also present in Albian sediments of Tunisia and Algeria, and in Cenomanian sediments of Egypt and Morocco. In Africa, baryonychines were common in the Aptian, and then replaced by spinosaurines in the Albian and Cenomanian.<ref name="BuffetautandOuaja2002">{{cite journal |last1=Buffetaut |first1=Eric |last2=Ouaja |first2=Mohamed |title=A new specimen of Spinosaurus (Dinosauria, Theropoda) from the Lower Cretaceous of Tunisia, with remarks on the evolutionary history of the Spinosauridae |journal=Bulletin de la Société Géologique de France |date=1 September 2002 |volume=173 |issue=5 |pages=415–421 |doi=10.2113/173.5.415 |bibcode=2002BSGF..173..415B |hdl=2042/216 |url=http://doc.rero.ch/record/14728/files/PAL_E1854.pdf |hdl-access=free }}</ref> such as in the Kem Kem beds of Morocco, which housed an ecosystem containing many large coexisting predators.<ref name="HendrickxMateusandBuffetaut2016">{{cite journal |last1=Hendrickx |first1=Christophe |last2=Mateus |first2=Octávio |last3=Buffetaut |first3=Eric |title=Morphofunctional Analysis of the Quadrate of Spinosauridae (Dinosauria: Theropoda) and the Presence of Spinosaurus and a Second Spinosaurine Taxon in the Cenomanian of North Africa. |journal=PLOS ONE |date=6 January 2016 |volume=11 |issue=1 |article-number=e0144695 |doi=10.1371/journal.pone.0144695 |pmid=26734729 |pmc=4703214 |bibcode=2016PLoSO..1144695H |doi-access=free }}</ref><ref name="RMetal10" /> A fragment of a spinosaurine lower jaw from the Early Cretaceous was also reported from Tunisia, and referred to ''Spinosaurus''.<ref name="BuffetautandOuaja2002" /> Spinosaurinae's range also extended to South America, particularly Brazil, with the discoveries of ''Irritator challengeri, Angaturama limai,'' and ''Oxalaia quilombensis.''<ref name="Buffetautetal.20042" /><ref name="DiscOxalaia" /> There was also a fossil tooth in Argentina which has been referred to the Spinosauridae by Leonardo Salgado and colleagues.<ref name="Salgadoetal.2009">{{cite journal |last1=Salgado |first1=Leonardo |last2=Canudo |first2=José I. |last3=Garrido |first3=Alberto C. |last4=Ruiz-Omeñaca |first4=José I. |last5=García |first5=Rodolfo A. |last6=de la Fuente |first6=Marcelo S. |last7=Barco |first7=José L. |last8=Bollati |first8=Raúl |title=Upper Cretaceous vertebrates from El Anfiteatro area, Río Negro, Patagonia, Argentina |journal=Cretaceous Research |date=June 2009 |volume=30 |issue=3 |pages=767–784 |doi=10.1016/j.cretres.2009.01.001 |bibcode=2009CrRes..30..767S }}</ref> This referral is doubted by Gengo Tanaka et al., who offers ''Hamadasuchus'', a crocodilian, as the most likely animal of origin for these teeth.<ref name="Tanaka2010">{{cite book |last1=Hasegawa |first1=Yoshikazu |first2=Gengo |last2=Tanaka |first3=Yuji |last3=Takakuwa |first4=Satoshi |last4=Koike |chapter=Fine sculptures on a tooth of Spinosaurus (Dinosauria, Theropoda) from Morocco |title=Bulletin of Gunma Museum of Natural History |volume=14 |year=2010 |pages=11–20 |url=http://www.gmnh.pref.gunma.jp/wp-content/uploads/bulletin14_2.pdf }}</ref>

Partial skeletons and numerous fossil teeth indicate spinosaurids were widespread in Asia; three taxa—all spinosaurines—have been named: ''Siamosaurus suteethorni'' from Thailand, "''Sinopliosaurus''" ''fusuiensis'' from China, and ''Ichthyovenator laosensis'' from Laos.<ref name="AXRK122" /><ref name="BuffetautandOuaja2002" /><ref name="Honeetal.2010">{{cite journal |last1=Hone |first1=David W. E. |last2=Xing |first2=X. U. |last3=De-You |first3=Wang |title=A PROBABLE BARYONYCHINE (THEROPODA: SPINOSAURIDAE) TOOTH FROM THE UPPER CRETACEOUS OF HENAN PROVINCE, CHINA |journal=Vertebrata PalAsiatica |date=15 March 2010 |volume=48 |issue=1 |page=19 |url=http://www.vertpala.ac.cn/EN/Y2010/V48/I1/19 }}</ref> Spinosaurid teeth have been found in Malaysia; they were the first dinosaur remains discovered in the country.<ref name="sciencedaily">{{cite web|url=https://www.sciencedaily.com/releases/2014/02/140224204737.htm|title=First discovery of dinosaur fossils in Malaysia|author=ResearchSEA|date=2014|website=ScienceDaily}}</ref> Some intermediate specimens extend the known range of spinosaurids past the youngest dates of named taxa. A single theropod tooth attributed to Baryonychinae was found in the mid-Santonian Majiacun Formation of Henan, China,<ref name="Honeetal.2010" /> but this tooth lacked spinosaurid synapomorphies,<ref>{{Cite journal|last1=Katsuhiro|first1=Kubota|last2=Yuji|first2=Takakuwa|last3=Yoshikazu|first3=Hasegawa|date=2017|title=Second discovery of a spinosaurid tooth from the Sebayashi Formation (Lower Cretaceous), Kanna Town, Gunma Prefecture, Japan|url=http://www.gmnh.pref.gunma.jp/wp-content/uploads/Second-discovery-of-a-spinosaurid-tooth-from-the-Sebayashi-Formation-Lower-Cretaceous-Kanna-Town-Gunma-Prefecture-Ja1.pdf|journal=Bulletin of the Gunma Museum of Natural History|volume=21|pages=1–6}}</ref><ref>{{Cite journal|author1=Eric Buffetaut |author2=Suravech Suteethorn |author3=Varavudh Suteethorn |author4=Haiyan Tong |author5=Kamonrak Wongko |year=2019 |title=Spinosaurid teeth from the Lower Cretaceous of Ko Kut, eastern Thailand |journal=Annales de Paléontologie |volume=105 |issue=3 |pages=239–243 |doi=10.1016/j.annpal.2019.03.006 |bibcode=2019AnPal.105..239B |s2cid=146225359 |url=https://hal.science/hal-03488796v1/file/S0753396919300187.pdf }}</ref><ref>{{cite journal|last1=Puntanon |first1=K. |last2=Samathi |first2=A. |year=2025 |title=The occurrence of Spinosauridae (Dinosauria: Theropoda) during the Cretaceous of Asia: Implications for biogeography and distribution |journal=Thai Geoscience Journal |volume=6 |issue=9 |pages=13–28 |url=https://ph03.tci-thaijo.org/index.php/TGJ/article/view/3652 }}</ref> and it was reclassified as a theropod of uncertain affinities, either an allosauroid or a sister taxon of abelisaurids in 2023.<ref>{{cite journal |last1=Barker |first1=Chris T. |last2=Naish |first2=Darren |last3=Gostling |first3=Neil J. |title=Isolated tooth reveals hidden spinosaurid dinosaur diversity in the British Wealden Supergroup (Lower Cretaceous) |journal=PeerJ |date=2023 |volume=11 |article-number=e15453 |doi=10.7717/peerj.15453|pmid=37273543 |pmc=10239232 |doi-access=free }}</ref> In 2025, Olmedo-Romaña et al. described putative theropod teeth with similarities to spinosaurid teeth from the strata of the Fundo El Triunfo Formation (Peru) interpreted as spanning all or part of the Campanian–Maastrichtian interval, and tentatively classified the studied fossil material as remains of late-surviving members of the family Spinosauridae, as well as the first record of the group from western South America.<ref name=Ameghiniana2025>{{Cite journal |last1=Olmedo-Romaña |first1=G. J. |last2=Wilson Mantilla |first2=J. A. |last3=Tejada |first3=J. V. |last4=Antoine |first4=P. O. |last5=Burga-Castillo |first5=M. A. |last6=Aliaga-Castillo |first6=A. V. |last7=Varas-Malca |first7=R. |last8=Benites-Palomino |first8=A. |last9=Salas-Gismondi |first9=R. |title=Theropod and sauropod dinosaurs from the Campanian-Maastrichtian Bagua Basin of Perú, including the first possible report of Spinosauridae in western South America |year=2025 |journal=Ameghiniana |volume=62 |issue=4 |pages=259–287 |doi=10.5710/AMGH.13.02.2025.3627 |bibcode=2025Amegh..62.3627O |url=https://www.ameghiniana.org.ar/index.php/ameghiniana/article/view/3627 |url-access=subscription }}</ref> In the same year, Barker, Naish and Gostling argued that these teeth lack key features of spinosaurid dentition, and that they most likely represent crocodylomorph teeth.<ref>{{cite journal|author1=Barker, Chris T.|author2=Naish, D.|author3=Gostling, Neil J.|year=2025|title=Insufficient Evidence for Spinosaurid Survival into the Latest Cretaceous: A Comment on Olmedo-Romaña et al. (2025)|journal=Ameghiniana|volume=62|issue=6|pages=572–580|url=https://www.ameghiniana.org.ar/index.php/ameghiniana/libraryFiles/downloadPublic/157|doi=10.5710/AMGH.10.12.2025.3673}}</ref> At la Cantalera-1, a site in the early Barremian Blesa Formation in Treul, Spain, two types of spinosaurid teeth were found, and they were assigned, tentatively, as indeterminate spinosaurine and baryonychine taxa.<ref name="AlonsoandCanudo2016">{{cite journal |last1=Alonso |first1=Antonio |last2=Canudo |first2=José Ignacio |title=On the spinosaurid theropod teeth from the early Barremian (Early Cretaceous) Blesa Formation (Spain) |journal=Historical Biology |date=17 August 2016 |volume=28 |issue=6 |pages=823–834 |doi=10.1080/08912963.2015.1036751 |bibcode=2016HBio...28..823A |s2cid=131023889 }}</ref> An indeterminate spinosaurid was discovered in the Early Cretaceous Eumeralla Formation, Australia.<ref>{{Cite news|url=http://www.australiangeographic.com.au/news/2011/06/australian-spinosaur-unearthed|title=Australian 'Spinosaur' unearthed|work=Australian Geographic|access-date=2018-04-15|language=en}}</ref> It is known from a single 4 cm long partial cervical vertebra, designated NMV P221081. It is missing most of the neural arch. The specimen is from a juvenile estimated to be about 2 to 3 meters long (6–9 ft). Out of all spinosaurids, it most closely resembles ''Baryonyx''.<ref name="BarrettBenson2011">{{cite journal |last1=Barrett |first1=Paul M. |last2=Benson |first2=Roger B. J. |last3=Rich |first3=Thomas H. |last4=Vickers-Rich |first4=Patricia |title=First spinosaurid dinosaur from Australia and the cosmopolitanism of Cretaceous dinosaur faunas |journal=Biology Letters |date=23 December 2011 |volume=7 |issue=6 |pages=933–936 |doi=10.1098/rsbl.2011.0466 |pmid=21693488 |pmc=3210678 |bibcode=2011BiLet...7..933B }}</ref> In 2019, it was suggested that the vertebra instead belonged to a megaraptorid theropod, as opposed to a spinosaur.<ref name="poropat2019">{{cite journal | title=New megaraptorid (Dinosauria: Theropoda) remains from the Lower Cretaceous Eumeralla Formation of Cape Otway, Victoria, Australia | journal=Journal of Vertebrate Paleontology |article-number = e1666273| year=2019 | doi=10.1080/02724634.2019.1666273|last1 = Poropat|first1 = Stephen F.|last2 = White|first2 = Matt A.|last3 = Vickers-Rich|first3 = Patricia|last4 = Rich|first4 = Thomas H.| volume=39 | issue=4 | bibcode=2019JVPal..39E6273P | s2cid=208603798 | url=https://figshare.com/articles/journal_contribution/9963197 }}</ref>

==Timeline of genera== <timeline> ImageSize = width:800px height:auto barincrement:15px PlotArea = left:10px bottom:50px top:10px right:10px Period = from:-201 till:-66 TimeAxis = orientation:horizontal ScaleMajor = unit:year increment:10 start:-200 ScaleMinor = unit:year increment:1 start:-201 TimeAxis = orientation:hor AlignBars = justify Colors = #legends id:CAR value:claret id:ANK value:rgb(0.4,0.3,0.196) id:HER value:teal id:HAD value:green id:OMN value:blue id:black value:black id:white value:white id:jurassic value:rgb(0.2,0.7,0.79) id:earlyjurassic value:rgb(0,0.69,0.89) id:middlejurassic value:rgb(0.52,0.81,0.91) id:latejurassic value:rgb(0.74,0.89,0.97) id:cretaceous value:rgb(0.5,0.78,0.31) id:earlycretaceous value:rgb(0.63,0.78,0.65) id:latecretaceous value:rgb(0.74,0.82,0.37) BarData= bar:eratop bar:space bar:periodtop bar:space bar:NAM1 bar:NAM2 bar:NAM3 bar:NAM4 bar:NAM5 bar:NAM6 bar:NAM7 bar:NAM8 bar:NAM9 bar:NAM10 bar:NAM11 bar:NAM12 bar:NAM13 bar:NAM14 bar:space bar:period bar:space bar:era PlotData= align:center textcolor:black fontsize:M mark:(line,black) width:25 shift:(7,-4) bar:periodtop from: -201 till: -174 color:earlyjurassic text:Early from: -174 till: -163 color:middlejurassic text:Middle from: -163 till: -145 color:latejurassic text:Late from: -145 till: -100 color:earlycretaceous text:Early from: -100 till: -66 color:latecretaceous text:Late bar:eratop from: -201 till: -145 color:jurassic text:Jurassic from: -145 till: -66 color:cretaceous text:Cretaceous PlotData= align:left fontsize:M mark:(line,white) width:5 anchor:till align:left color:cretaceous bar:NAM1 from:-130 till:-129 text:Siamosaurus color:cretaceous bar:NAM2 from:-130 till:-125 text:Baryonyx color:cretaceous bar:NAM3 from:-129 till:-125 text:Vallibonavenatrix color:cretaceous bar:NAM4 from:-129 till:-125 text:Ceratosuchops color:cretaceous bar:NAM5 from:-129 till:-125 text:Riparovenator color:cretaceous bar:NAM6 from:-129 till:-125 text:Protathlitis color:cretaceous bar:NAM7 from:-125 till:-120 text:Suchosaurus color:cretaceous bar:NAM8 from:-125 till:-112 text:Cristatusaurus color:cretaceous bar:NAM9 from:-121 till:-112 text:Suchomimus color:cretaceous bar:NAM10 from:-115 till:-110 text:Ichthyovenator color:cretaceous bar:NAM11 from:-110 till:-108 text:Irritator color:cretaceous bar:NAM12 from:-100 till:-98 text:Oxalaia color:cretaceous bar:NAM13 from:-100 till:-94 text:Sigilmassasaurus color:cretaceous bar:NAM14 from:-112 till:-93.5 text:Spinosaurus PlotData= align:center textcolor:black fontsize:M mark:(line,black) width:25 bar:period from: -201 till: -174 color:earlyjurassic text:Early from: -174 till: -163 color:middlejurassic text:Middle from: -163 till: -145 color:latejurassic text:Late from: -145 till: -100 color:earlycretaceous text:Early from: -100 till: -66 color:latecretaceous text:Late bar:era from: -201 till: -145 color:jurassic text:Jurassic from: -145 till: -66 color:cretaceous text:Cretaceous </timeline>

== Timeline of genera descriptions ==

<timeline> ImageSize = width:1000px height:auto barincrement:15px PlotArea = left:10px bottom:50px top:10px right:10px

Period = from:1820 till:2050 TimeAxis = orientation:horizontal ScaleMajor = unit:year increment:50 start:1820 ScaleMinor = unit:year increment:10 start:1820 TimeAxis = orientation:hor AlignBars = justify

Colors = #legends id:CAR value:claret id:ANK value:rgb(0.4,0.3,0.196) id:HER value:teal id:HAD value:green id:OMN value:blue id:black value:black id:white value:white id:1900s value:rgb(0.94,0.25,0.24) id:2000s value:rgb(0.2,0.7,0.79) id:2000syears value:rgb(0.52,0.81,0.91) id:1900syears value:rgb(0.95,0.56,0.45) id:1700s value:rgb(0.5,0.78,0.31) id:1700syears value:rgb(0.63,0.78,0.65) id:latecretaceous value:rgb(0.74,0.82,0.37) id:1800syears value:rgb(0.95,0.98,0.11) id:paleogene value:rgb(0.99,0.6,0.32) id:paleocene value:rgb(0.99,0.65,0.37) id:eocene value:rgb(0.99,0.71,0.42) id:oligocene value:rgb(0.99,0.75,0.48) id:1800s value:rgb(0.999999,0.9,0.1) id:miocene value:rgb(0.999999,0.999999,0) id:pliocene value:rgb(0.97,0.98,0.68) id:quaternary value:rgb(0.98,0.98,0.5) id:pleistocene value:rgb(0.999999,0.95,0.68) id:holocene value:rgb(0.999,0.95,0.88)

BarData= bar:eratop bar:space bar:periodtop bar:space bar:NAM1 bar:NAM2 bar:NAM3 bar:NAM4 bar:NAM5 bar:NAM6 bar:NAM7 bar:NAM8 bar:NAM9 bar:NAM10 bar:NAM11 bar:NAM12 bar:NAM13 bar:NAM14 bar:NAM15 bar:NAM16 bar:space bar:period bar:space bar:era

PlotData= align:center textcolor:black fontsize:M mark:(line,black) width:25 shift:(7,-4) bar:periodtop from: 1820 till: 1830 color:1800syears text:20s from: 1830 till: 1840 color:1800syears text:30s from: 1840 till: 1850 color:1800syears text:40s from: 1850 till: 1860 color:1800syears text:50s from: 1860 till: 1870 color:1800syears text:60s from: 1870 till: 1880 color:1800syears text:70s from: 1880 till: 1890 color:1800syears text:80s from: 1890 till: 1900 color:1800syears text:90s from: 1900 till: 1910 color:1900syears text:00s from: 1910 till: 1920 color:1900syears text:10s from: 1920 till: 1930 color:1900syears text:20s from: 1930 till: 1940 color:1900syears text:30s from: 1940 till: 1950 color:1900syears text:40s from: 1950 till: 1960 color:1900syears text:50s from: 1960 till: 1970 color:1900syears text:60s from: 1970 till: 1980 color:1900syears text:70s from: 1980 till: 1990 color:1900syears text:80s from: 1990 till: 2000 color:1900syears text:90s from: 2000 till: 2010 color:2000syears text:00s from: 2010 till: 2020 color:2000syears text:10s from: 2020 till: 2030 color:2000syears text:20s from: 2030 till: 2040 color:2000syears text:30s from: 2040 till: 2050 color:2000syears text:40s

bar:eratop from: 1820 till: 1900 color:1800s text:19th from: 1900 till: 2000 color:1900s text:20th from: 2000 till: 2050 color:2000s text:21st

PlotData= align:left fontsize:M mark:(line,white) width:5 anchor:till align:left

color:1800s bar:NAM1 at:1841 mark:(line,black) text:Suchosaurus color:1900s bar:NAM2 at:1915 mark:(line,black) text:Spinosaurus color:1900s bar:NAM3 at:1986 mark:(line,black) text:Baryonyx color:1900s bar:NAM4 at:1986 mark:(line,black) text:Siamosaurus color:1900s bar:NAM5 at:1996 mark:(line,black) text:Angaturama color:1900s bar:NAM6 at:1996 mark:(line,black) text:Irritator color:1900s bar:NAM7 at:1996 mark:(line,black) text:Sigilmassasaurus color:1900s bar:NAM8 at:1998 mark:(line,black) text:Suchomimus color:1900s bar:NAM9 at:1998 mark:(line,black) text:Cristatusaurus color:2000s bar:NAM10 at:2008 mark:(line,black) text:Sinopliosaurus fusuiensis color:2000s bar:NAM11 at:2011 mark:(line,black) text:Oxalaia color:2000s bar:NAM12 at:2012 mark:(line,black) text:Ichthyovenator color:2000s bar:NAM13 at:2019 mark:(line,black) text:Vallibonavenatrix color:2000s bar:NAM14 at:2021 mark:(line,black) text:Ceratosuchops color:2000s bar:NAM15 at:2021 mark:(line,black) text:Riparovenator color:2000s bar:NAM16 at:2023 mark:(line,black) text:Protathlitis

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bar:period from: 1820 till: 1830 color:1800syears text:20s from: 1830 till: 1840 color:1800syears text:30s from: 1840 till: 1850 color:1800syears text:40s from: 1850 till: 1860 color:1800syears text:50s from: 1860 till: 1870 color:1800syears text:60s from: 1870 till: 1880 color:1800syears text:70s from: 1880 till: 1890 color:1800syears text:80s from: 1890 till: 1900 color:1800syears text:90s from: 1900 till: 1910 color:1900syears text:00s from: 1910 till: 1920 color:1900syears text:10s from: 1920 till: 1930 color:1900syears text:20s from: 1930 till: 1940 color:1900syears text:30s from: 1940 till: 1950 color:1900syears text:40s from: 1950 till: 1960 color:1900syears text:50s from: 1960 till: 1970 color:1900syears text:60s from: 1970 till: 1980 color:1900syears text:70s from: 1980 till: 1990 color:1900syears text:80s from: 1990 till: 2000 color:1900syears text:90s from: 2000 till: 2010 color:2000syears text:00s from: 2010 till: 2020 color:2000syears text:10s from: 2020 till: 2030 color:2000syears text:20s from: 2030 till: 2040 color:2000syears text:30s from: 2040 till: 2050 color:2000syears text:40s

bar:era from: 1820 till: 1900 color:1800s text:19th from: 1900 till: 2000 color:1900s text:20th from: 2000 till: 2050 color:2000s text:21st </timeline>

== See also ==

*''Spinosaurus'' *''Oxalaia'' *''Sigilmassasaurus'' *''Baryonyx''

==References== {{Reflist}}

==External links== {{Commons category}} {{Wikispecies}}

* [http://theropoddatabase.com/Megalosauroidea.htm#Spinosauridae Spinosauridae] on the Theropod Database

Category:Spinosauridae Category:Dinosaur families Category:Cretaceous dinosaurs