Құрып кеткен динозаврлар туысы - Struthiosaurus

Extinct genus of dinosaurs

Struthiosaurus (Latin struthio = ostrich + Greek sauros = lizard) is a genus of nodosaurid dinosaurs, from the Late Cretaceous period (Santonian Maastrichtian) of Austria, Romania, France and Hungary in Europe. It was a small dinosaur, measuring in length and weighing .

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. 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. and S. languedocensis Garcia and Pereda Suberbiola, 2003, based on UM2 OLV D50 A–G CV, a partial skeleton found in 1998 in France. It is the namesake of the nodosaurine tribe Struthiosaurini, members of which are found only in Europe. 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. 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. 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. 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)

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')". He later corrected its name to Acanthopholidae. Walter Coombs in 1978 stated it was a nodosaurid. 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. The cladogram below shows the results of the 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.

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.