Batyrosaurus (lat.) Is a genus of herbivorous ornithopod dinosaurs from the superfamily Hadrosauroidea from the Cretaceous of Asia . The typical and only species of Batyrosaurus rozhdestvenskyi was named and described by Pascal Godfroix and colleagues in 2012. The name of the clan is formed from the word batyr , which means "warrior", "hero". The species name was given in honor of the famous Soviet paleontologist A. K. Rozhdestvensky for his pioneering work on the study of Central Asian iguanodonts [1] .
| † Batyrosaurus |
| Scientific classification |
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| No rank : | Bilateral symmetrical |
| Infraclass : | Archosauromorphs |
| No rank : | Archosauriformes |
| Infrastructure : | † Ornithopods |
| Parvotryad : | † Iguanodonts |
| Superfamily : | † Hadrosavroids |
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| International scientific name |
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Batyrosaurus Godefroit et al. , 2012 |
| Single view |
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† Batyrosaurus rozhdestvenskyi
Godefroit et al. , 2012 |
Geochronology86.3—72.1 Ma | million years | Period | Era | Aeon |
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| 2,588 | Even | | | Ka | F
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th | | 23.03 | Neogene | | 66.0 | Paleogen | | 145.5 | a piece of chalk | M
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th | | 199.6 | Yura | | 251 | Triassic | | 299 | Permian | P
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th | | 359.2 | Carbon | | 416 | Devonian | | 443.7 | Silur | | 488.3 | Ordovician | | 542 | Cambrian | | 4570 | Precambrian |
◄ Nowadays◄ Cretaceous-Paleogene extinction◄ Triassic extinction◄ Mass Permian Extinction◄ Devonian extinction◄ Ordovician-Silurian extinction◄ Cambrian explosion |
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Content
Holotype AEHM 4/1 was found at the Akkurgan locality in the layers of the Bostobin Formation dated by the Santon - Campanian , Kyzylorda Oblast , Kazakhstan .
The holotype is a partial skeleton, including a partial skull, lower jaw, about 60 isolated teeth, both sternum, right humerus, left radius, fragments of the metacarpal bones and carpal phalanges [1] .
Batyrosaurus is a non-hadrosaurid hadrosaroid diagnosed by the following autapomorphies : the parietal bone forms long caudal lobes, which lie above the upper occipital bone and overlap with scaly bones, but remain well separated from the paracipital wings (a sign that Bactrosaurus has ); the frontal bones are rostrocaudally elongated, their length is almost 1.7 times greater than the width; the lateral side of the rostral process of the zygomatic bone has a deep horizontal groove under the lacrimal facet; the articular surface of the arched bone has an opening [1] .
The silicone endocrane Batyrosaurus was obtained. The front part of the endocranes reflects the shape of the brain, because where the final brain should be, vallecules (folds) are distinguishable, indicating that at least this part of the brain was in direct contact with the bones. This is the first time that vallecula have been discovered in a non-hadrosaurid iguanodont. The presence of the vallecula indicates that the shape and size of the endocrane accurately reflects the overall organization of the brain. Like other ornithopods, the general organization of the Batyrosaurus brain is more reminiscent of that of crocodiles than of birds or pterosaurs .
The endocrane has a length of 105 mm and a maximum width of 45.8 mm. It is relatively narrow except for the rounded and enlarged rostral part. The terminal brain is round and has a pear-shaped dorsal projection. The hemispheres of the brain are wide and slightly compressed dorsoventrally. There are two constrictions on the brain. One is located behind the end brain, and the other, more noticeable, is behind the large triangular peak above the midbrain . On this narrowing are the inner ear and semicircular canals . The midbrain and hindbrain are undifferentiated.
The large triangular peak protrudes dorsally above the midbrain and extends rostrally and caudally to the hemisphere and hindbrain. Similar peaks are observed in endocranes of many dinosaurs, for example, in Allosaurus , Tyrannosaurus , Majungasaurus , and to a lesser extent in Hypacrosaurus , Corythosaurus and Lambeosaurus , as well as in Iguanodon and Mantellisaurus . Perhaps in the dural space there was a well-developed pineal body ( pineal gland ). The pineal bodies are present in modern birds, and there is also evidence of the presence of pineal-like tissue in alligators .
The caudal part of the pituitary fossa and paired internal carotid arteries passing ventrodorsally through the fossa are visible on the endocrane.
The left inner ear is well preserved. Three semicircular canals form loops. The front is longer than the rear, and horizontal is the shortest of them. The large, strongly curved semicircular canals that are observed in Batyrosaurus correspond to mobile locomotion . Moreover, the enlarged anterior semicircular canal reflects adaptation to bipedal locomotion, as in the case of theropods and bipedal basal ceratops . Therefore, based on the curvature and relative size of the semicircular canals, it can be assumed that Batyrosaurus was an active bipedal animal [1] .
To clarify the phylogenetic position of Batyrosaurus , an analysis was performed using 108 characters for 25 taxa. In the consensus tree, Batyrosaurus is located in the Hadrosauroidea treasure in a more advanced position to Bolong , Jinzhousaurus , Equijubus and Altirhinus . Together with Probactrosaurus and other advanced Hadrosauroidea Batyrosaurus forms a clade [1] .
In 2017, as part of a study of the phylogenetic relationships of Eolambia, MacDonald and colleagues performed an analysis using 135 characters for 47 taxa as part of a study of the phylogenetic relationships of Eolambia . On the majority consensus tree (the tree of strict consensus is poorly resolved) Batyrosaurus fell into a vast geographic and stratigraphic treasure of basal hadrosaroids, including African Ouranosaurus , European Proa and Morelladon, and Asian Altirhinus , Koshisaurus and Sirindhorna . The treasure existed from barrem to alb , but possibly to santon, if the dating of Batyrosaurus is accurate.
Cladogram based on a study by MacDonald and colleagues in 2017 (majority agreement tree) [2] :
| Hadrosauriformes |
| Iguanodon |
| | Hadrosauroidea |
| Mantellisaurus |
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| Ouranosaurus |
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| Altirhinus |
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| Morelladon |
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| Proa |
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| Batyrosaurus |
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| Gongpoquansaurus |
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| Probactrosaurus |
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| Hadrosauromorpha |
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- ↑ 1 2 3 4 5 Pascal Godefroit; Francois Escuillie; Yuri L. Bolotsky; Pascaline Lauters (2012). "A New Basal Hadrosauroid Dinosaur from the Upper Cretaceous of Kazakhstan." In Godefroit, P. Bernissart Dinosaurs and Early Cretaceous Terrestrial Ecosystems. Indiana University Press. pp. 335-358.
- ↑ Andrew T. McDonald; Terry A. Gates; Lindsay E. Zanno; Peter J. Makovicky. 2017. Anatomy, taphonomy, and phylogenetic implications of a new specimen of Eolambia caroljonesa (Dinosauria: Ornithopoda) from the Cedar Mountain Formation, Utah, USA. PLoS ONE 12 (5): e0176896.