Tanystropheidae

Tanystropheidae Temporal range:Triassic,
Skeletal reconstruction ofTanystropheus longobardicus
Life restoration ofLangobardisaurus
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Clade:	Archosauromorpha
Clade:	†Tanysauria
Family:	†Tanystropheidae Gervais, 1858
Genera
List of genera †Amotosaurus †Augustaburiania †Cosesaurus †Elessaurus? †Exilisuchus? †Fuyuansaurus? †Gracilicollum? †Gwyneddosaurus †Langobardisaurus †Luxisaurus †Macrocnemus †Ozimek? †Pectodens? †Protanystropheus? †Raibliania †Sclerostropheus? †Sharovipteryx? †Tanystropheus †Tanytrachelos

Tanystropheidaeis an extinctfamilyofarchosauromorphreptiles that lived throughout theTriassicPeriod, often considered to be "protorosaurs".They are characterized by their long, stiff necks formed from elongatedcervical vertebraewith very longcervical ribs.Members of the group include both terrestrial and aquatic forms. While some tanystropheids were small lizard-like animals, other tanystropheids such asTanystropheuswere large animals that had necks that were several meters long, longer than the rest of their bodies.

Tanystropheids are known fromEurope,Asia(Russia,China,andSaudi Arabia),North Americaand probablySouth America(Brazil).The presence of tanystropheids in Europe and China indicate that they lived along much of the coastline of theTethys Ocean.However, species in western North America are found in terrestrial deposits, suggesting that as a group, tanystropheids were ecologically diverse.

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.

Phylogeny

In2021,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 unstableOTUexclusions. 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”,andRaibliania calligarisi) are pruned after the analysis to minimizepolytomies:

Archosauromorpha

Jesairosaurus Protorosaurus Prolacerta Czatkowiella Sharovipterygidae(Ozimek volans) Fuyuansaurus Dinocephalosauridae Protanystropheus Pectodens Dinocephalosaurus Tanystropheidae Macrocnemus bassanii Macrocnemus fuyuanensis Augustaburiania Amotosaurus Langobardisaurus AMNH FARB 7206 Sclerostropheus Tanystropheus hydroides GMPKU P 1527 T. cf. hydroides Tanystropheus longobardicus Crocopoda Allokotosauria Rhynchosauria Teyujagua Archosauriformes

A later 2024 study grouped Tanystropheidae along withTrachelosauridaein the new cladeTanysauria.