| Tanystropheus | |
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| Modelled Tanystropheus skeleton | |
Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Clade: | Archosauromorpha |
| Family: | †Tanystropheidae |
| Genus: | †Tanystropheus Meyer, 1852 |
| Type species | |
| †Tanystropheus conspicuus nomen dubium Von Meyer, 1855
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| Other species | |
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| Synonyms | |
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Genus synonymy
Species synonymy
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Tanystropheus (Greek: τανυ~ 'long' + στροφευς 'hinged') is an extinct genus of archosauromorph reptile which lived during the Triassic Period in Europe, Asia, and North America. It is recognisable by its extremely elongated neck, longer than the torso and tail combined. The neck was composed of 13 vertebrae strengthened by extensive cervical ribs. Tanystropheus is one of the most well-described non-archosauriform archosauromorphs, known from numerous fossils, including nearly complete skeletons. Some species within the genus may have reached a total length of 6 meters (20 ft), making Tanystropheus the longest non-archosauriform archosauromorph as well.[1] Tanystropheus is the namesake of the family Tanystropheidae, a clade collecting many long-necked Triassic archosauromorphs previously described as "protorosaurs" or "prolacertiforms".
Tanystropheus contains at least two valid species as well as fossils which cannot be referred to a specific species. The type species of Tanystropheus is T. conspicuus, a dubious name applied to particularly large fossils from Germany and Poland. Complete skeletons are common in the Besano Formation at Monte San Giorgio, on the border of Italy and Switzerland. Monte San Giorgio fossils belong to two species: the smaller T. longobardicus and the larger T. hydroides. These two species were formally differentiated in 2020 primarily on the basis of their strongly divergent skull anatomy. When T. longobardicus was first described in 1886, it was initially mistaken for a pterosaur and given the name "Tribelesodon". Starting in the 1920s, systematic excavations at Monte San Giorgio unearthed many more Tanystropheus fossils, revealing that the putative wing bones of "Tribelesodon" were actually neck vertebrae.
Most Tanystropheus fossils hail from marine or coastal deposits of the Middle Triassic epoch (Anisian and Ladinian stages), with some exceptions. For example, a vertebra from Nova Scotia was recovered from primarily freshwater sediments. The youngest fossils in the genus are a pair of well-preserved skeletons from the Zhuganpo Formation, a geological unit in China which dates to the earliest part of the Late Triassic (early Carnian stage).[2] The oldest putative fossils belong to "T. antiquus", a European species from the latest part of the Early Triassic (late Olenekian stage). T. antiquus had a proportionally shorter neck than other Tanystropheus species, so some paleontologists consider that T. antiquus deserves a separate genus, Protanystropheus.
The lifestyle of Tanystropheus has been the subject of much debate.[3] Tanystropheus is unknown from drier environments and its neck is rather stiff and ungainly, suggesting a reliance on water. Conversely, the limbs and tail lack most adaptations for swimming and closely resemble their equivalents in terrestrial reptiles. Recent studies have supported an intermediate position, reconstructing Tanystropheus as an animal equally capable on land and in the water. Despite its length, the neck was lightweight and stabilized by tendons, so it would not been a fatal hindrance to terrestrial locomotion. The hindlimbs and the base of the tail were large and muscular, capable of short bursts of active swimming in shallow water. Tanystropheus was most likely a piscivorous ambush predator: the narrow subtriangular skull of T. longobardicus is supplied with three-cusped teeth suited for holding onto slippery prey, while the broader skull of T. hydroides bears an interlocking set of large curved fangs similar to the fully aquatic plesiosaurs.
- ^ Elbein, Asher (12 August 2020). "Making Sense of 'One of the Most Baffling Animals That Ever Lived' - Important mysteries have been solved about a reptile with a giraffe-like neck that hunted prey 242 million years ago". The New York Times. Retrieved 14 August 2020.
- ^ Rieppel, Olivier; Jiang, Da-Yong; Fraser, Nicholas C.; Hao, Wei-Cheng; Motani, Ryosuke; Sun, Yuan-Lin; Sun, Zuo-Yu (2010). "Tanystropheus cf. T. Longobardicus from the early Late Triassic of Guizhou Province, southwestern China". Journal of Vertebrate Paleontology. 30 (4): 1082–1089. Bibcode:2010JVPal..30.1082R. doi:10.1080/02724634.2010.483548. JSTOR 40864387. S2CID 86315078.
- ^ Dal Sasso, C. and Brillante, G. (2005). Dinosaurs of Italy. Indiana University Press. ISBN 0-253-34514-6, ISBN 978-0-253-34514-1.