Testudinata is the group of all

tetrapod Tetrapods (; ) are four-limbed vertebrate animals constituting the superclass Tetrapoda (). It includes extant and extinct amphibians, sauropsids ( reptiles, including dinosaurs and therefore birds) and synapsids ( pelycosaurs, extinct t ...

s with a true turtle shell. It includes both modern

turtle Turtles are an order of reptiles known as Testudines, characterized by a special shell developed mainly from their ribs. Modern turtles are divided into two major groups, the Pleurodira (side necked turtles) and Cryptodira (hidden necked t ...

s (Testudines) and many of their extinct, shelled relatives (stem-turtles). Though it was first coined as the group containing turtles by

Jacob Theodor Klein Jacob Theodor Klein (nickname ''Plinius Gedanensium''; 15 August 1685 – 27 February 1759) was a German jurist, historian, botanist, zoologist, mathematician and diplomat in service of Polish King August II the Strong. Life Klein was born on ...

in 1760, it was first defined in the modern sense by Joyce and colleagues in 2004. Testudinata does not include the primitive stem-turtle ''

Odontochelys ''Odontochelys semitestacea'' (meaning "toothed turtle with a half-shell") is a Late Triassic relative of turtles. Before ''Pappochelys'' was discovered and ''Eunotosaurus'' was redescribed, ''Odontochelys'' was considered the oldest undisputed m ...

'', which only had the bottom half of a shell. A recent phylogenetic tree of Testudinata included

Angolachelonia Angolachelonia is a clade of extinct turtles from the Late Jurassic to Paleogene of Eurasia. The group is defined as all taxa derived from the ancestor of the type genus ''Angolachelys'' and ''Solnhofia'', a definition that could potentially ...

and

Testudines Turtles are an order of reptiles known as Testudines, characterized by a special shell developed mainly from their ribs. Modern turtles are divided into two major groups, the Pleurodira (side necked turtles) and Cryptodira (hidden necked t ...

as sister-taxa and subgroups of Testudinata.

Classification

The cladogram below follows an analysis by Jérémy Anquetin in 2012.

References

{{Taxonbar, from=Q16114972 Reptile taxonomy Norian first appearances Extant Late Triassic first appearances Taxa named by Jacob Theodor Klein