Tsylmosuchus Temporal range: Early Triassic Induan–Olenekian |
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Scientific classification | |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Reptilia |
Clade: | Archosauriformes |
Genus: |
†Tsylmosuchus Sennikov, 1990 |
Species | |
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Tsylmosuchus is an extinct genus of archosauriform reptile. It is known from the southern Urals region of Russia. Tsylmosuchus occurred throughout the Olenekian age of the Early Triassic. Some of the strata from which Tsylmosuchus has been found are Induan in age, making it one of the earliest archosaurs. The genus is named after the Tsilma River, near where fossils have been found. Three species have been named, all based on single incomplete specimens: the type species T. jakovlevi, T. samariensis, and T. donensis.Tsylmosuchus was originally classified among crocodile-line archosaurs (pseudosuchians) as part of the family Rauisuchidae; however, the fragmentary remains do not show any of the distinguishing features of rauisuchids or even pseudosuchians in general, so Tsylmosuchus has more recently been interpreted as an indeterminate archosauriform. Given the lack of diagnostic material for the three species that have been named, they are also probably not distinct from each other.
Tsylmosuchus is known primarily from vertebrae. These vertebrae are similar to those of rauisuchids from East Africa. Like several early rauisuchians, such as Energosuchus and Vytshegdosuchus, Tsylmosuchus has elongated cervical vertebrae, giving it a relatively long neck.
Nesbitt (2009) suggested that elongated cervical vertebrae were present in numerous archosauriform clades, and that the length of the cervical vertebrae depended on the position in the presacral column, as seen in the poposauroid Arizonasaurus and the non-archosaurian archosauriform Guchengosuchus. The holotypes of each of the three species consist of a single cervical vertebra, which does not bear any other clear autapomorphies. Furthermore, the material referred to these species cannot be shown to belong to the same taxa as the holotypes. Thus, Nesbitt (2009) considered all three species to represent invalid archosauriforms.