Tanystropheidae is an extinct
family of
archosauromorph reptiles that lived throughout the
Triassic Period, often considered to be "
protorosaurs". They are characterized by their long, stiff necks formed from elongated
cervical vertebrae with very long
cervical ribs. Members of the group include both terrestrial and aquatic forms. While some tanystropheids were small lizard-like animals, other tanystropheids such as Tanystropheus were large animals that had necks that were several meters long, longer than the rest of their bodies.
Tanystropheids are known from
Europe,
Asia (
Russia,
China, and
Saudi Arabia),
North America[5] and probably
South America (
Brazil).[6] The presence of tanystropheids in Europe and China indicate that they lived along much of the coastline of the
Tethys Ocean.[7] However, species in western North America are found in terrestrial deposits, suggesting that as a group, tanystropheids were ecologically diverse.[5]
Relationships among tanystropheid species have been difficult to resolve because most specimens were flattened during fossilization and are preserved two-dimensionally. Three-dimensional fossils are known from Europe and North America.[5]
Phylogeny
In
2021, a phylogenetic study was conducted by S. Spiekman, N. Fraser, and T. Scheyer in an attempt to clarify the systematics of "
protorosaur" groups. A total of 16 individual trees were found using different character scoring methods and unstable
OTU exclusions. The following cladogram shows the results of analysis 3A. In this analysis, ratio and ordered characters are treated as such, and 5 out of 40 OTUs (Macrocnemus obristi,
Elessaurus gondwanoccidens,
Tanytrachelos ahynis,
Tanystropheus “conspicuus”, and Raibliania calligarisi) are pruned after the analysis to minimize
polytomies:[8]
^Wang, W.; Spiekman, S. N. F.; Zhao, L.; Rieppel, O.; Scheyer, T. M.; Fraser, N. C.; Li, C. (2023). "A new long-necked archosauromorph from the Guanling Formation (Anisian, Middle Triassic) of southwestern China and its implications for neck evolution in tanystropheids". The Anatomical Record.
doi:
10.1002/ar.25216.
PMID37029530.
S2CID258028261.
^Lu, Y.-T.; Liu, J. (2023). "A new tanystropheid (Diapsida: Archosauromorpha) from the Middle Triassic of SW China and the biogeographical origin of Tanystropheidae". Journal of Systematic Palaeontology. 21 (1).
Bibcode:
2023JSPal..2150778L.
doi:
10.1080/14772019.2023.2250778.
S2CID263634664.
^
abAdam C. Pritchard; Hans-Dieter Sues (2019). "Postcranial remains of Teraterpeton hrynewichorum (Reptilia: Archosauromorpha) and the mosaic evolution of the saurian postcranial skeleton". Journal of Systematic Palaeontology. 17 (20): 1745–1765.
Bibcode:
2019JSPal..17.1745P.
doi:
10.1080/14772019.2018.1551249.
S2CID91446492.
^
abcPritchard, Adam C; et al. (2015). "Late Triassic tanystropheids (Reptilia, Archosauromorpha) from northern New Mexico (Petrified Forest Member, Chinle Formation) and the biogeography, functional morphology, and evolution of Tanystropheidae". Journal of Vertebrate Paleontology. 35 (2): e911186.
Bibcode:
2015JVPal..35E1186P.
doi:
10.1080/02724634.2014.911186.
S2CID130089407.
^Rieppel, O.; Jiang, D. Y.; Fraser, N. C.; Hao, W. C.; Motani, R.; Sun, Y. L.; Sun, Z. Y. (2010). "Tanystropheus cf. T. Longobardicus from the early Late Triassic of Guizhou Province, southwestern China". Journal of Vertebrate Paleontology. 30 (4): 1082.
Bibcode:
2010JVPal..30.1082R.
doi:
10.1080/02724634.2010.483548.
S2CID86315078.