Tanystropheidae is an extinct

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

archosauromorph Archosauromorpha (Greek for "ruling lizard forms") is a clade of diapsid reptiles containing all reptiles more closely related to archosaurs (such as crocodilians and dinosaurs, including birds) than to lepidosaurs (such as tuataras, lizards, a ...

reptiles that lived throughout the

Triassic The Triassic ( ; sometimes symbolized 🝈) is a geologic period and system which spans 50.5 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.4 Mya. The Triassic is t ...

Period, often considered to be " protorosaurs". They are characterized by their long, stiff necks formed from elongated

cervical vertebrae In tetrapods, cervical vertebrae (: vertebra) are the vertebrae of the neck, immediately below the skull. Truncal vertebrae (divided into thoracic and lumbar vertebrae in mammals) lie caudal (toward the tail) of cervical vertebrae. In saurop ...

with very long

cervical rib Cervical ribs are the ribs of the neck in many tetrapods. In most mammals, including humans, cervical ribs are not normally present as separate structures. They can, however, occur as a pathology. In humans, pathological cervical ribs are usually no ...

s. Members of the group include both terrestrial and aquatic forms. While some tanystropheids were small lizard-like animals, other tanystropheids such as ''

Tanystropheus ''Tanystropheus'' (~ 'long' + 'hinged') is an extinct genus of archosauromorph reptile which lived during the Triassic period, Triassic Period in Europe, Asia, and North America. It is recognisable by its extremely elongated neck, longer than t ...

'' were large animals that had necks that were several meters long, longer than the rest of their bodies. Tanystropheids are known from

Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

Asia Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which ...

(

Russia Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders ...

China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

, and

Saudi Arabia Saudi Arabia, officially the Kingdom of Saudi Arabia (KSA), is a country in West Asia. Located in the centre of the Middle East, it covers the bulk of the Arabian Peninsula and has a land area of about , making it the List of Asian countries ...

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

and probably

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

(

Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...

). The presence of tanystropheids in Europe and China indicate that they lived along much of the coastline of the

Tethys Ocean The Tethys Ocean ( ; ), also called the Tethys Sea or the Neo-Tethys, was a prehistoric ocean during much of the Mesozoic Era and early-mid Cenozoic Era. It was the predecessor to the modern Indian Ocean, the Mediterranean Sea, and the Eurasia ...

. 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

2021 Like the year 2020, 2021 was also heavily defined by the COVID-19 pandemic, due to the emergence of multiple Variants of SARS-CoV-2, COVID-19 variants. The major global rollout of COVID-19 vaccines, which began at the end of 2020, continued ...

, 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: A later 2024 study grouped Tanystropheidae along with

Trachelosauridae Trachelosauridae (also known as Dinocephalosauridae) is an extinct clade of archosauromorph reptiles that lived throughout the Triassic period. Like their close relatives the tanystropheids, they were " protorosaur"-grade archosauromorphs charact ...

in the new clade

Tanysauria Tanysauria (meaning "long lizards") is an extinct clade long-necked archosauromorph reptiles from the Triassic period of Europe, Asia, North America, and South America. It comprises the families Tanystropheidae and Trachelosauridae (found by the ...

References

Prehistoric reptile families Triassic reptiles Triassic first appearances Triassic extinctions Taxa named by Paul Gervais {{triassic-reptile-stub