Struthiosaurus

Struthiosaurus (Latin struthio = ostrich + Greek sauros = lizard) is one of the smallest known and most basal genera of nodosaurid dinosaurs, from the Late Cretaceous period (Santonian-Maastrichtian) of Austria, Romania, France and Hungary in Europe.[1] It was protected by body armour. Although estimates of its length vary, it may have been as small as 2.2 metres (7.2 ft) long.

Struthiosaurus
Temporal range: Late Cretaceous, 85–66 Ma
Struthiosaurus austriacus
Diagrams showing the known skeletal elements and hypothetical placement of osteoderms in S. austriacus
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Order: Ornithischia
Family: Nodosauridae
Subfamily: Struthiosaurinae
Genus: Struthiosaurus
Bunzel, 1871
Type species
Struthiosaurus austriacus
Bunzel, 1871
Species
  • S. austriacus Bunzel, 1871
  • S. transylvanicus Nopcsa, 1915
  • S. languedocensis
    Garcia and Pereda-Suberbiola, 2003
Synonyms
  • Crataeomus Seeley, 1881
  • Danubiosaurus Bunzel, 1871
  • Pleuropeltus Seeley, 1881

History of discovery

Struthiosaurus (8062141412)
Osteoderms of S. austriacus, from Lower Austria in the Naturhistorisches Museum (Vienna)

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 a 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.[2]

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 and only known species of the genus at the time was Struthiosaurus austriacus.[2] Bunzel stated that he only provisionally named the taxon and gave no etymology of the name. The generic name is derived from new Latin struthio, itself derived from Ancient Greek στρούθειος, stroutheios, "of the ostrich". Bunzel chose the name because of the birdlike morphology of the braincase.[2] The 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.[2] These British genera represented the best known thyreophoran 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, 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.[2] 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 paleontologists: S. austriacus Bunzel, 1871, based on holotype PIWU 2349/6; S. transylvanicus Nopcsa, 1915, based on BMNH R4966, a skull and partial skeleton from Romania;[3] and S. languedocensis Garcia and Pereda-Suberbiola, 2003, based on UM2 OLV-D50 A–G CV, a partial skeleton found in 1998 in France.[4] It is the namesake of the nodosaurid subfamily Struthiosaurinae, members of which are found only in Europe.[5]

Struthiosaurus Nopsca 1915
Outdated illustration drawn in 1915 by Nopsca

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.[6] 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.[7] Another European ankylosaurid, Rhodanosaurus ludguensis Nopsca, 1929, from Campanian-Maastrichtian-age rocks of southern France, is now regarded as a nomen dubium and referred to Nodosauridae incertae sedis.[8]

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 dorsal vertebrae. It differs from S. austriacus in the shape of the ischium. (Vickaryous, 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')".[2]

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 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.[9] He later corrected its name to Acanthopholidae.[10] Walter Coombs in 1978 stated it was a nodosaurid.[11]

Cladistic analysis of Struthiosaurus indicates that the taxon is a basal 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.[12] The cladogram below follows the most resolved topology from a 2011 analysis by paleontologists Richard S. Thompson, Jolyon C. Parish, Susannah C. R. Maidment and Paul M. Barrett.[13]

Struthiosaurus occitanicus humerus
Humerus of Struthiosaurus
Nodosauridae

Antarctopelta

Mymoorapelta

Hylaeosaurus

Anoplosaurus

Tatankacephalus

Horshamosaurus

Polacanthinae

Gargoyleosaurus

Hoplitosaurus

Gastonia

Peloroplites

Polacanthus

Struthiosaurus

Zhejiangosaurus

Hungarosaurus

Animantarx

Niobrarasaurus

Nodosaurus

Pawpawsaurus

Sauropelta

Silvisaurus

Stegopelta

Texasetes

Edmontonia

Panoplosaurus

See also

References

  1. ^ Struthiosaurus in The Dinosaur Encyclopaedia at Dino Russ's Lair
  2. ^ a b c d e f Bunzel, E (1871). "Die Reptilfauna der Gosaformation in der Neuen Welt bei Wiener-Neustadt" (PDF). Abhandlungen der Kaiserlich-Königlichen Geologischen Reichsanstalt. 5: 1–18.
  3. ^ F. Nopcsa, 1915, "Die dinosaurier der Siebenbürgischen landesteile Ungarns", Mitteilungen aus dem Jahrbuche der Königlich-Ungarischen Geologischen Reichsanstalt 23: 1-24
  4. ^ G. Garcia and X. Pereda-Suberbiola, 2003, "A new species of Struthiosaurus (Dinosauria: Ankylosauria) from the Upper Cretaceous of Villeveyrac (southern France)", Journal of Vertebrate Paleontology 23(1): 156-165
  5. ^ Kirkland, J. I.; Alcalá, L.; Loewen, M. A.; Espílez, E.; Mampel, L.; Wiersma, J. P. (2013). Butler, Richard J, ed. "The Basal Nodosaurid Ankylosaur Europelta carbonensis n. gen., n. sp. From the Lower Cretaceous (Lower Albian) Escucha Formation of Northeastern Spain". PLoS ONE 8 (12): e80405.
  6. ^ H.G. Seeley, 1881, "The reptile fauna of the Gosau Formation preserved in the Geological Museum of the University of Vienna", Quarterly Journal of the Geological Society of London 37(148): 620-707
  7. ^ F. Nopcsa, 1918, "Leipsanosaurus n. gen. ein neuer thyreophore aus der Gosau", Földtani Közlöny 48: 324-328
  8. ^ 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
  9. ^ F. Nopcsa. 1902. "Notizen über cretacische Dinosaurier". Sitzungsberichte der Mathematisch-Naturwissenschaftlichen Classe der Kaiserlichen Akademie der Wissenschaften III(1): 93-114
  10. ^ Nopcsa, B.F. (1928). "Palaeontological notes on reptiles. V. On the skull of the Upper Cretaceous dinosaur Euoplocephalus". Geologica Hungarica, Series Palaeontologica. 1 (1): 1–84.
  11. ^ W.P. Coombs. 1978. "Forelimb muscles of the Ankylosauria (Reptilia, Ornithischia)". Journal of Paleontology 52(3): 642-657
  12. ^ Ösi, A. (2005). "Hungarosaurus tormai, a new ankylosaur (Dinosauria) from the Upper Cretaceous of Hungary". Journal of Vertebrate Paleontology. 25 (2): 370–383. doi:10.1671/0272-4634(2005)025[0370:HTANAD]2.0.CO;2.
  13. ^ Richard S. Thompson; Jolyon C. Parish; Susannah C. R. Maidment; Paul M. Barrett (2011). "Phylogeny of the ankylosaurian dinosaurs (Ornithischia: Thyreophora)". Journal of Systematic Palaeontology. 10 (2): 301–312. doi:10.1080/14772019.2011.569091.
1871 in paleontology

Paleontology or palaeontology is the study of prehistoric life forms on Earth through the examination of plant and animal fossils. This includes the study of body fossils, tracks (ichnites), burrows, cast-off parts, fossilised feces (coprolites), palynomorphs and chemical residues. Because humans have encountered fossils for millennia, paleontology has a long history both before and after becoming formalized as a science. This article records significant discoveries and events related to paleontology that occurred or were published in the year 1871.

1881 in paleontology

Paleontology or palaeontology is the study of prehistoric life forms on Earth through the examination of plant and animal fossils. This includes the study of body fossils, tracks (ichnites), burrows, cast-off parts, fossilised feces (coprolites), palynomorphs and chemical residues. Because humans have encountered fossils for millennia, paleontology has a long history both before and after becoming formalized as a science. This article records significant discoveries and events related to paleontology that occurred or were published in the year 1881.

Ankylosaurinae

Ankylosaurinae is a subfamily of ankylosaurid dinosaurs, existing from the Early Cretaceous about 105 million years ago until the end of the Late Cretaceous, about 66 mya. Many genera are included in the clade, such as Ankylosaurus, Pinacosaurus, Euoplocephalus, and Saichania.

Cairanoolithus

Cairanoolithus is an oogenus of dinosaur egg which is found in Southwestern Europe. The eggs are large (15–19 centimetres or 5.9–7.5 inches in diameter) and spherical. Their outer surface is either smooth, or covered with a subdued pattern of ridges interspersed with pits and grooves. Multiple fossil egg clutches are known but the nest structure is unclear.

The parent of Cairanoolithus is probably some kind of non-ornithopod ornithischian, possibly the nodosaurid Struthiosaurus.

The eggs were first named in 1994, when the two oospecies were classified in distinct oogenera as Cairanoolithus dughii and Dughioolithus roussetensis. They are now considered to belong in a single oogenus, possibly even a single oospecies. Though it has been classified as a megaloolithid, Cairanoolithus is now placed in its own oofamily, Cairanoolithidae.

Dinosaurs of Romania

The dinosaurs of Romania are exclusively Cretaceous. Lowermost Cretaceous dinosaurs come from a bauxite mine in the Bihor County (northwest Romania) that has yielded thousands of disarticulated bones. Uppermost Cretaceous dinosaurs have been known from the Hațeg Basin (south Transylvania) since the end of the 19th century, mostly as bone concentrations (fossiliferous pockets); more recently, nests with dinosaur eggs, including hatchlings, have been found in Hațeg. Although separated by a gap of approximately 60 million years, the two dinosaur faunas from Romania share some common features: predominance of ornithopods, absence of large theropods (although the Maastrichtian Hațeg assemblage has several small theropods), and, in general, the small size of the individuals (see also insular dwarfism).

The discovery of dinosaur bones in a bauxite mine at Cornet-Brusturi, near Oradea (Bihor County) was made accidentally by two miners in 1978 during ore exploitation. Almost at the same time, research in the already known Uppermost Cretaceous dinosaur-bearing deposits from the Hațeg Basin were restarted by Dan Grigorescu, after an interruption of more than 60 years, since Franz Nopcsa’s work in the region.

The Berriasian bauxite deposits at Cornet have yielded approximately 10,000 bones and bone fragments, mainly from ornithopod dinosaurs and rarer pterosaurs. The region was located to the east of the Piemont-Liguria Ocean, and during the Early Cretaceous formed an archipelago of coral and volcanic islands, not too dissimilar to today's Indonesia or the Caribbean. As the Apulian Plate moved northwest towards the end of the Cretaceous and the beginning of the uplift of the Alpide belt, the offshore Hațeg Island was formed at the rim of the shrinking Tethys Ocean.

Among the species that lived here are: Zalmoxes, Telmatosaurus, Balaur, Rhabdodon, Magyarosaurus and Struthiosaurus. Other prehistoric creatures that lived among them, without being dinosaurs are: Allodaposuchus and Hatzegopteryx.

Emanuel Bunzel

Emanuel Bunzel,1828 - 1895, was an Austrian paleontologist.

In 1871, he described a skull fragment found in an Austrian coal mine years before by colleagues Ferdinand Stoliczka and Eduard Suess as the type specimen for the dinosaur genus Struthiosaurus, the first discovered in the region. Another dinosaur he described initially as a species of Iguanodon (I. suessii) has since been reassigned to the genus Mochlodon.

Europelta

Europelta is an extinct genus of struthiosaurine nodosaurid dinosaur known from the Early Cretaceous (early Albian stage) lower Escucha Formation of Teruel Province, northeastern Spain. It contains a single species, Europelta carbonensis. It is known from two associated partial skeletons, and represents the most complete ankylosaur known from Europe.

Gosau Group

The Gosau Group (German: Gosau-Gruppe) is a geological stratigraphic group in Austria, Germany and western Slovakia whose strata date back to the Late Cretaceous to Eocene. Dinosaur remains are among the fossils that have been recovered from the group. It is divided into two subgroups, the Lower Gosau Subgroup which dates from 90-75 ma and the Upper Gosau Subgroup which dates from 83.5-50 ma, the sequence is largely marine, but the Grünbach Formation represents a terrestrial deposit.

Hungarosaurus

Hungarosaurus tormai is a herbivorous nodosaurid ankylosaur from the Upper Cretaceous (Santonian) Csehbánya Formation of the Bakony Mountains of western Hungary. It is the most completely known ankylosaur from the Cretaceous of Europe. Ankylosaur material had been known from Europe since the 19th century, with finds having been previously made in England, Austria, western Romania, France, and northern Spain.

List of European dinosaurs

Dinosaurs evolved partway through the Triassic period of the Mesozoic era, around 230 Ma (million years ago). At that time, the earth had one supercontinental landmass, called Pangaea, of which Europe was a part. So it remained throughout the Triassic. By the start of the Jurassic period, some 30 million years later, the supercontinent began to split into Laurasia and Gondwana. The largest inlet from Panthalassa, the superocean that surrounded Pangaea, was called the Tethys Ocean, and as this inlet cut deeper into the supercontinent, much of Europe was flooded.

By the Cretaceous, from 145 to 66 million years ago, the continents were beginning to approach their present shapes, but not their present positions, and Europe remained tropical. At times, it was a chain of island-microcontinents including Baltica and Iberia.

Europe is relatively rich in fossils from the Jurassic-Cretaceous boundary, and much of what is known about European dinosaurs dates from this time. During the Maastrichtian the end of the Cretaceous dinosaurs were dominating western and Central Europe as the Tremp Formation in Spain dates back to that age. Examples of dinosaurs from Maastrichtian Europe are Struthiosaurus and Canardia.

List of dinosaur genera

This list of dinosaurs is a comprehensive listing of all genera that have ever been included in the superorder Dinosauria, excluding class Aves (birds, both living and those known only from fossils) and purely vernacular terms.

The list includes all commonly accepted genera, but also genera that are now considered invalid, doubtful (nomen dubium), or were not formally published (nomen nudum), as well as junior synonyms of more established names, and genera that are no longer considered dinosaurs. Many listed names have been reclassified as everything from birds to crocodilians to petrified wood. The list contains 1559 names, of which approximately 1192 are considered either valid dinosaur genera or nomina dubia.

Mongolostegus

Mongolostegus is a genus of stegosaur from the Early Cretaceous (Aptian-Albian) of Mongolia. The type and only species is M. exspectabilis, known from a single specimen previously under the nomen nudum Wuerhosaurus mongoliensis.

Nodosauridae

Nodosauridae is a family of ankylosaurian dinosaurs, from the Late Jurassic to the Late Cretaceous period of what are now North America, Europe, Asia, Africa, and Antarctica.

Polacanthinae

Polacanthinae is a grouping of ankylosaurs, possibly primitive nodosaurids. Polacanthines are late Jurassic to early Cretaceous in age, and appear to have become extinct about the same time a land bridge opened between Asia and North America.Polacanthines were somewhat more lightly armoured than more advanced ankylosaurids and nodosaurids. Their spikes were made up of thin, compact bone with less reinforcing collagen than in the heavily armoured nodosaurids. The relative fragility of polacanthine armour suggests that it may have been as much for display as defense.

Rhadinosaurus

Rhadinosaurus alcimus (meaning "slender lizard") is a genus of nodosaurid ankylosaur first described in 1881 by Harry Govier Seeley, based on remains uncovered in Austria. It was a herbivore that lived around 84.9 to 70.6 million years ago (during the Late Cretaceous period).

Silvisaurus

Silvisaurus, from the Latin silva "woodland" and Greek sauros "lizard", is a nodosaurid ankylosaur from the middle Cretaceous period.

Struthiosaurinae

Struthiosaurinae is a subfamily of ankylosaurian dinosaurs from the Cretaceous of Europe. It is defined as "the most inclusive clade containing Europelta but not Cedarpelta, Peloroplites, Sauropelta or Edmontonia" while being reinstated for a newly recognized clade of basal nodosaurids. Struthiosaurinae appeared at about exactly the same time as the North American subfamily Nodosaurinae. Struthiosaurines range all across the Cretaceous, the oldest genus being Europelta at an age of 112 Ma and the youngest being Struthiosaurus at about 85–66 Ma.

It was originally mentioned by Franz Nopcsa in 1923 as a subfamily of Acanthopholidae, along with the previously defined Acanthopholinae. The family has gone through many taxonomic revisions since it was defined by Nopcsa in 1902. It is now recognized as a junior synonym of the family Nodosauridae. The subfamily now includes the genera Anoplosaurus, Europelta, Hungarosaurus, and Struthiosaurus, designated as the type genus. Because of the instability of Acanthopholis, the generic namesake of Acanthopholinae, and its current identification as a nomen dubium, Struthiosaurinae, the next named group, was decidedly used over the older one.

A review of ankylosaur osteoderms was published in 2000, and reviewed the armour of Struthiosaurinae. The group was represented by the single genus Struthiosaurus, known from head, cervical, dorsal, sacral, and caudal scutes. Only a few head osteoderms were identified, so it is unknown how much of the skull was armoured. Many cervical and dorsal scutes have been preserved alongside species of Struthiosaurus. They include cervical bands, which are groups of osteoderms fused together and attached to the vertebrae, and large spines found on the shoulders of nodosaurids like Sauropelta and Edmontonia, although it is not known if the spines were fused like the later of separate like the former. It is quite possible that small ovoid scutes found on Struthiosaurus could have formed a pelvic shield like polacanthids. The caudal scutes of struthiosaurines are small and rough. Even though osteoderms are well-known, it is not certain where they were positioned on the body.

Tatisaurus

Tatisaurus is a genus of ornithischian dinosaur from the Early Jurassic from the Lower Lufeng Formation in Yunnan Province in China. Little is known as the remains are fragmentary.

Tianzhenosaurus

Tianzhenosaurus (Tianzhen + Greek sauros="lizard") is a genus of ankylosaurid dinosaurs discovered in Tianzhen County, at Kangdailiang near Zhaojiagou Village, in Shanxi Province, China, in the Late Cretaceous Huiquanpu Formation. Thus far, a virtually complete skull and postcranial skeleton have been assigned to the genus, which is monotypic (T. youngi Pang & Cheng, 1998).

This was a medium-sized ankylosaurian, the skull measuring 28 cm (11 in) in length, with a total body length around 4 m (13 ft).

Vickaryous et al. (2004) placed Tianzhenosaurus within the Ankylosauridae, nested as the sister group to Pinacosaurus. Some authors have suggested that Tianzhenosaurus is actually a junior synonym of Saichania chulsanensis.

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