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{{Short description|Extinct genus of dinosaurs}}
{{distinguish|Struthiomimus}}
{{Automatic taxobox
| fossil_range = [[Late Cretaceous]], {{Fossil range|85|66}}
| image = Struthiosaurus (8062141412).jpg
| image_caption = Osteoderms of ''S. austriacus'', from [[Lower Austria]] in the [[Naturhistorisches Museum (Vienna)]]
| taxon = Struthiosaurus
| authority = Bunzel, 1871
| type_species = {{extinct}}'''''Struthiosaurus austriacus'''''
| type_species_authority = [[Emanuel Bunzel|Bunzel]], [[1871 in paleontology|1871]]
| subdivision_ranks = Other [[species]]
| subdivision =
*{{extinct}}'''''S. transylvanicus''''' [[Franz Nopcsa von Felső-Szilvás|Nopcsa]], 1915
*{{extinct}}'''''S. languedocensis''''' Garcia and Pereda-Suberbiola, 2003
| synonyms =
*'''''Crataeomus''''' Seeley, 1881
*'''''Danubiosaurus''''' Bunzel, 1871
*'''''Pleuropeltus''''' Seeley, 1881
}}

'''''Struthiosaurus''''' ([[Latin]] ''struthio'' = ostrich + [[Greek language|Greek]] ''sauros'' = lizard) is a [[genus]] of [[Nodosauridae|nodosaurid]] [[dinosaur]]s, from the Late [[Cretaceous]] period ([[Santonian]]-[[Maastrichtian]]) of [[Austria]], [[Romania]], [[France]] and [[Hungary]] in [[Europe]].<ref name=dinoencyc>[https://web.archive.org/web/20071006233752/http://www.dinoruss.com/de_4/5a77ff5.htm ''Struthiosaurus'' in The Dinosaur Encyclopaedia] at Dino Russ's Lair</ref><ref>{{Cite journal |last=Pereda-Suberbiola |first=Javier |date=1992 |title=A revised census of European Late Cretaceous nodosaurids(Ornithischia: Ankylosauria): last occurrence and possible extinction scenarios |url=https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-3121.1992.tb00613.x |journal=Terra Nova |language=en |volume=4 |issue=6 |pages=641–648 |doi=10.1111/j.1365-3121.1992.tb00613.x |bibcode=1992TeNov...4..641P |issn=1365-3121|url-access=subscription }}</ref> It was a small dinosaur, measuring {{cvt|2|-|3|m|ft}} in length and weighing {{cvt|300|-|400|kg|lbs}}.<ref>{{aut|Atilla Ősi, & E. Prondvai}}, 2013, "Sympatry of two ankylosaurs (''Hungarosaurus'' and cf. ''Struthiosaurus'') in the Santonian of Hungary", ''Cretaceous Research'' '''44''': 58–63</ref><ref name="Schade2022">{{cite journal |last1=Schade |first1=Marco |last2=Stumpf |first2=Sebastian |last3=Kriwet |first3=Jürgen |last4=Kettler |first4=Christoph |last5=Pfaff |first5=Cathrin |title=Neuroanatomy of the nodosaurid Struthiosaurus austriacus (Dinosauria: Thyreophora) supports potential ecological differentiations within Ankylosauria |journal=Scientific Reports |date=7 January 2022 |volume=12 |issue=1 |pages=144 |doi=10.1038/s41598-021-03599-9 |pmid=34996895 |pmc=8741922 |bibcode=2022NatSR..12..144S }}</ref><ref>{{cite book|last=Paul|first=Gregory S.|year=2010|chapter=Ornithischians|title=The Princeton Field Guide to Dinosaurs|pages=214–316|publisher=Princeton: Princeton University Press|doi=10.1515/9781400836154.214|isbn=9781400836154 }}</ref><ref>{{cite journal|first1=A.|last1=Ősi|first2=L.|last2=Makádi|year=2009|title=New remains of ''Hungarosaurus tormai'' (Ankylosauria, Dinosauria) from the Upper Cretaceous of Hungary: skeletal reconstruction and body mass estimation|journal=Paläontologische Zeitschrift |volume=83|issue=2|pages=227–245|doi=10.1007/s12542-009-0017-5|bibcode=2009PalZ...83..227O }}</ref>

==History of discovery==
In 1859, geologist [[Eduard Suess]] at the ''Gute Hoffnung'' coal mine at [[Muthmannsdorf]] near [[Wiener Neustadt]] in Austria, discovered a dinosaur tooth on a stone pile. With the help of mine intendant Pawlowitsch it was attempted to find the source of the fossil material. The search proved fruitless at first but ultimately a thin marl layer was discovered, intersected by an obliquely sloping mine shaft, which contained an abundant number of various bones. These were subsequently excavated by Suess and [[Ferdinand Stoliczka]]. The marl was a [[fresh water]] deposit, now considered part of the [[Grünbach Formation]].<ref name = "bunzel71"/>

The finds were stored in the museum of the [[University of Vienna]] but received little attention until they were studied by [[Emanuel Bunzel]] in 1870. In 1871, Bunzel published a treatise describing the fossils and naming several new genera and species. One of them was the genus ''Struthiosaurus'' based on a single partial portion of the posterior end of the skull, largely consisting of the braincase. The [[type species|type]] and only known species of the genus at the time was ''Struthiosaurus austriacus''.<ref name = "bunzel71">{{cite journal|last=Bunzel|first=E|year=1871|title=Die Reptilfauna der Gosaformation in der Neuen Welt bei Wiener-Neustadt|journal=Abhandlungen der Kaiserlich-Königlichen Geologischen Reichsanstalt|volume=5|pages=1–18|url=http://www.zobodat.at/stable/pdf/AbhGeolBA_5_0001-0018.pdf}}</ref> Bunzel stated that he only provisionally named the [[taxon]] and gave no [[etymology]] of the name. The generic name is derived from [[Neo-Latin]] ''struthio'', itself derived from [[Ancient Greek]] στρούθειος, ''stroutheios'', "of the ostrich". Bunzel chose the name because of the birdlike morphology of the braincase.<ref name = "bunzel71"/> The [[specific name (zoology)|specific name]] refers to the provenance from Austria.

Apart from the braincase, Bunzel unknowingly described other material of ''Struthiosaurus''. He recognized that there were bones and osteoderms of armoured dinosaurs among the finds and referred them to a ''[[Scelidosaurus]]'' sp. and a ''[[Hylaeosaurus]]'' sp.<ref name = "bunzel71"/> These British genera represented the best known [[thyreophora]]n forms found at the time. Bunzel also discovered two rib fragments which had a very puzzling build. They were double-headed but the upper rib head, the [[Tuberculum costae|tuberculum]], was short and positioned in such a way that it could not possibly touch the vertebra, if the shaft was oriented in the usual vertical position. He assumed that only the lower capitulum connected to the vertebral body. A rib touching the vertebra with a single surface is normal for lizards, though in their case the rib heads are fused into a single [[synapophysis]]. Bunzel therefore concluded that the ribs belonged to a giant lizard. In analogy to ''[[Mosasaurus]]'', the giant lizard named after the [[River Maas]], he named this lizard ''Danubiosaurus anceps'', after the [[Danube]]. The specific name ''anceps'' means "double-headed" in [[Latin]], highlighting the, for a lizard, exceptional trait of having double-headed ribs.<ref name = "bunzel71"/> In fact the ribs were those of ''Struthiosaurus''. In Ankylosauria, the rump is so flat that the upper part of the rib shafts sticks out sideways, which rotates the short tuberculum to the [[diapophysis]], its vertebral contact facet.

Many [[species]] have been referred to ''Struthiosaurus'', most based on very fragmentary and nondiagnostic material. Three valid species are recognized by [[paleontologist]]s: ''S. austriacus'' Bunzel, 1871, based on [[holotype]] PIWU 2349/6; ''S. transylvanicus'' [[Franz Nopcsa von Felső-Szilvás|Nopcsa]], 1915, based on BMNH R4966, a skull and partial skeleton from Romania;<ref>F. Nopcsa, 1915, "Die dinosaurier der Siebenbürgischen landesteile Ungarns", ''Mitteilungen aus dem Jahrbuche der Königlich-Ungarischen Geologischen Reichsanstalt'' '''23''': 1-24</ref> and ''S. languedocensis'' Garcia and Pereda-Suberbiola, 2003, based on UM2 OLV-D50 A–G CV, a partial skeleton found in 1998 in France.<ref>{{cite journal |last1=Garcia |first1=Géraldine |last2=Suberbiola |first2=Xabier Pereda |title=A new species of Struthiosaurus (Dinosauria: Ankylosauria) from the Upper Cretaceous of Villeveyrac (southern France) |journal=Journal of Vertebrate Paleontology |date=11 April 2003 |volume=23 |issue=1 |pages=156–165 |doi=10.1671/0272-4634(2003)23[156:ANSOSD]2.0.CO;2 |s2cid=140174401 }}</ref> It is the namesake of the [[Nodosaurinae|nodosaurine]] tribe [[Struthiosaurini]], members of which are found only in Europe.<ref>{{cite journal |last1=Kirkland |first1=James I. |last2=Alcalá |first2=Luis |last3=Loewen |first3=Mark A. |last4=Espílez |first4=Eduardo |last5=Mampel |first5=Luis |last6=Wiersma |first6=Jelle P. |title=The Basal Nodosaurid Ankylosaur Europelta carbonensis n. gen., n. sp. from the Lower Cretaceous (Lower Albian) Escucha Formation of Northeastern Spain |journal=PLOS ONE |date=2 December 2013 |volume=8 |issue=12 |pages=e80405 |doi=10.1371/journal.pone.0080405 |pmid=24312471 |pmc=3847141 |bibcode=2013PLoSO...880405K |doi-access=free }}</ref>

[[File:Struthiosaurus Nopsca 1915.png|thumb|left|Outdated illustration drawn in 1915 by Nopcsa]]
A number of invalid taxa have been shown to be junior synonyms of ''Struthiosaurus austriacus'', most of them created when [[Harry Govier Seeley]] in 1881 revised the Austrian material.<ref>{{cite journal |last1=Seeley |first1=H. G. |title=The Reptile Fauna of the Gosau Formation preserved in the Geological Museum of the University of Vienna |journal=Quarterly Journal of the Geological Society |date=1 February 1881 |volume=37 |issue=1–4 |pages=620–706 |doi=10.1144/GSL.JGS.1881.037.01-04.49 |bibcode=1881QJGS...37..620S |s2cid=219235284 }}</ref> They include: ''Danubiosaurus anceps'' Bunzel, 1871; ''Crataeomus pawlowitschii'' Seeley, 1881; ''Crataeomus lepidophorus'' Seeley 1881; ''Pleuropeltis suessii'' Seeley, 1881; ''Rhadinosaurus alcimus'' Seeley 1881, ''Hoplosaurus ischyrus'' Seeley 1881 and ''Leipsanosaurus noricus'' Nopcsa, 1918.<ref>F. Nopcsa, 1918, "''Leipsanosaurus'' n. gen. ein neuer thyreophore aus der Gosau", ''Földtani Közlöny'' '''48''': 324-328</ref> Another European ankylosaurid, ''Rhodanosaurus ludguensis'' Nopcsa, 1929, from [[Campanian]]-[[Maastrichtian]]-age rocks of southern [[France]], is now regarded as a ''[[nomen dubium]]'' and referred to Nodosauridae ''[[incertae sedis]]''.<ref>Pereda-Suberbiola, X., and Galton, P. M., 2001. Reappraisal of the nodosaurid ankylosaur ''Struthiosaurus austriacus'' Bunzel, 1871 from the Upper Cretaceous Gosau Beds of Austria. pp. 173-210 In: Carpenter, K., (ed.) ''The Armored Dinosaurs''. Indiana University Press, Bloomington & Indianapolis, 2001, pp. xv-526</ref>

The three valid species of ''Struthiosaurus'' differ from one another in that ''S. austriacus'' is smaller than ''S. transylvanicus'' and possesses less elongate [[cervical vertebrae]]. Also, though the quadrate-paroccipital process contact is fused in ''S. transylvanicus'', it is unfused in ''S. austriacus''. The skull of ''S. languedocensis'' is unknown, but the taxon differs from ''S. transylvanicus'' in the flatter shape of the [[Dorsum (biology)|dorsal]] vertebrae. It differs from ''S. austriacus'' in the shape of the [[ischium]]. (Vickaryous, [[Teresa Maryańska|Maryanska]], and Weishampel 2004)

==Classification==
Bunzel was very puzzled by the braincase. He knew that it belonged to a reptile instead of a mammal because of a single as opposed to a double-headed [[occipital condyle]]. The back of the head was otherwise not very reptilian as it was low, compact, fused and convex in a gradual curve towards the skull-roof. Lizards had a very different, more "open", [[occiput]]. Crocodiles were more similar but still had a concave skull rear. Bunzel considered whether it might be a dinosaur but in 1871 little dinosaurian occiput material had been described and it seemed to him that their skulls in this respect were more lizard-like. The only group showing a comparable rounding and fusion of skull bones were the birds. Bunzel sent a drawing and description to Professor [[Thomas Huxley]] in [[London]], at the time one of the few dinosaur experts. Huxley agreed that the braincase resembled that of a bird, commenting "This skull-fragment is more bird-like, than any thing [sic] I have yet seen". Knowing that Huxley had named a reptile order [[Ornithoscelida]] for forms sharing with birds certain traits in the pelvis and hindlimbs, Bunzel ended his description with the prediction that "with time, it might also be possible to create an order ''Ornithocephala'' ('Bird Heads')".<ref name = "bunzel71"/>

[[File:Stamps of Romania, 2005-013.jpg|thumb|A Romanian stamp illustration of ''Struthiosaurus'']]

Bunzel was correct in assuming an affinity with birds but this was because birds are themselves dinosaurs. In dinosaurs, the rear skull bones are generally strongly fused. Nodosaurids did [[convergent evolution|convergently]] develop a rounded skull. As the massive quadrates were lacking, the skull fragment gave a false impression of being lightly built. Ankylosaur material at the time was typically referred to the [[Scelidosauridae]] but because this was the first ankylosaur braincase to be described, the connection was not obvious. The first to understand it represented an armoured dinosaur was Nopcsa who in 1902 placed it in the [[Acanthopholididae]].<ref>F. Nopcsa. 1902. "Notizen über cretacische Dinosaurier". ''Sitzungsberichte der Mathematisch-Naturwissenschaftlichen Classe der Kaiserlichen Akademie der Wissenschaften'' '''III'''(1): 93-114</ref> He later corrected its name to [[Acanthopholidae]].<ref name=nopcsa1928b>{{cite journal|last=Nopcsa|first=B.F.|title=Palaeontological notes on reptiles. V. On the skull of the Upper Cretaceous dinosaur ''Euoplocephalus''|journal=Geologica Hungarica, Series Palaeontologica|year=1928|volume=1|issue=1|pages=1–84}}</ref> [[Walter Coombs]] in 1978 stated it was a nodosaurid.<ref>{{cite journal |last1=Coombs |first1=Walter P. |title=Forelimb Muscles of the Ankylosauria (Reptilia, Ornithischia) |journal=Journal of Paleontology |date=1978 |volume=52 |issue=3 |pages=642–657 |jstor=1303969 }}</ref>
[[File:Struthiosaurus occitanicus humerus.JPG|thumb|right|Humerus of ''Struthiosaurus'']]
[[Cladistic]] analysis of ''Struthiosaurus'' indicates that the taxon is a member of the [[Nodosauridae]] and suggested it may be one of the most basal ankylosaurs in the [[clade]] [[Ankylosauria]]. An analysis by Ösi in 2005, describing the taxon ''Hungarosaurus'', found that while being younger in age than other nodosaurids, ''Struthiosaurus'' was one of the more basal taxa, although many features could not be coded for it.<ref name = "osi05">{{cite journal|last=Ösi | first = A. | year = 2005 | title = ''Hungarosaurus tormai'', a new ankylosaur (Dinosauria) from the Upper Cretaceous of Hungary | journal = Journal of Vertebrate Paleontology | volume = 25 | issue = 2 | pages = 370–383 | doi = 10.1671/0272-4634(2005)025[0370:HTANAD]2.0.CO;2| s2cid = 131087368 }}</ref> The cladogram below shows the results of the [[2018 in paleontology|2018]] phylogenetic analysis of Rivera-Sylva and colleagues, resolving ''Struthiosaurus'' species within the clade [[Struthiosaurini]] as labelled by Madzia ''et al.'', with relationships outside Struthiosaurini excluded for simplicity.<ref name="madzia2021">{{cite journal|last1=Madzia|first1=D.|last2=Arbour|first2=V.M.|last3=Boyd|first3=C.A.|last4=Farke|first4=A.A.|last5=Cruzado-Caballero|first5=P.|last6=Evans|first6=D.C.|year=2021|title=The phylogenetic nomenclature of ornithischian dinosaurs|journal=PeerJ|volume=9|pages=e12362|doi=10.7717/peerj.12362|pmid=34966571|pmc=8667728 |doi-access=free }}</ref><ref name="rivera2018">{{cite journal|last1=Rivera-Sylva|first1=H.E.|last2=Frey|first2=E.|last3=Stinnesbeck|first3=W.|last4=Carbot-Chanona|first4=G.|last5=Sanchez-Uribe|first5=I.E.|last6=Guzmán-Gutiérrez|first6=J.R.|year=2018|title=Paleodiversity of Late Cretaceous Ankylosauria from Mexico and their phylogenetic significance|journal=[[Swiss Journal of Palaeontology]]|volume=137|issue=1 |pages=83–93|doi=10.1007/s13358-018-0153-1|s2cid=134924657|doi-access=free|bibcode=2018SwJP..137...83R }}</ref>

{{clade| style=font-size:85%; line-height:85%
|label1=[[Struthiosaurini]]
|1={{clade
|1={{clade
|1=''[[Hungarosaurus]]''
|2=''[[Europelta]]'' }}
|2={{clade
|1=''[[Pawpawsaurus]]''
|2=''[[Stegopelta]]''
|3='''''Struthiosaurus languedocensis'''''
|4={{clade
|1='''''Struthiosaurus transylvanicus'''''
|2='''''Struthiosaurus austriacus''''' }} }} }} }}

==Paleobiology==
[[File:Struthiosaurus austriacus size.png|thumb|Size comparison]]
[[File:1871 - Struthiosaurus.png|thumb|Life restoration]]
Examinations of the brain of ''Struthiosaurus'' published in 2022 suggest it had very poor hearing and relied mostly on its armor for defense against predators. Its flocculus was very small and its lagena were very short, suggesting it was very sluggish in nature as well as solitary.<ref name="Schade2022"></ref>

==See also==
{{Portal|Dinosaurs}}
* [[Timeline of ankylosaur research]]
* ''[[Cairanoolithus]]''

== References ==
{{Reflist}}

{{Thyreophora|N.}}
{{Taxonbar|from=Q136920}}
{{Authority control}}

[[Category:Nodosauridae]]
[[Category:Dinosaur genera]]
[[Category:Late Cretaceous dinosaurs]]
[[Category:Hațeg fauna]]
[[Category:Taxa named by Emanuel Bunzel]]
[[Category:Fossil taxa described in 1871]]
[[Category:Dinosaurs of France]]
[[Category:Dinosaurs of Romania]]
[[Category:Dinosaurs of Europe]]

Struthiosaurus - Revision history

imported>OAbot: Open access bot: url-access updated in citation with #oabot.