Testudinata is the group of all

tetrapod A tetrapod (; from Ancient Greek :wiktionary:τετρα-#Ancient Greek, τετρα- ''(tetra-)'' 'four' and :wiktionary:πούς#Ancient Greek, πούς ''(poús)'' 'foot') is any four-Limb (anatomy), limbed vertebrate animal of the clade Tetr ...

s with a true

turtle shell The turtle shell is a shield for the ventral and dorsal parts of turtles (the Order (biology), order Testudines), completely enclosing all the turtle's vital organs and in some cases even the head. It is constructed of modified bony elements such ...

. It includes both modern

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

s (Testudines) and many of their extinct, shelled relatives (stem-turtles), though excluding ''

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 ...

'' and ''

Eorhynchochelys ''Eorhynchochelys'' (meaning "dawn-beaked turtle" in Greek) is an extinct genus of stem-turtle from the Late Triassic Xiaowa Formation (or Wayao Member of the Falang Formation) of southwestern China. Description ''Eorhynchochelys'' is notable f ...

,'' which are placed in the more inclusive

Pantestudines Pantestudines or Pan-Testudines is the proposed group of all Reptile, reptiles more closely related to turtles than to any other living animal. It includes both modern turtles (crown group turtles, also known as Testudines) and all of their extin ...

''.''

History

It was first coined as the group containing turtles by Jacob Theodor Klein in 1760. In 1832-1836, Thomas Bell wrote a book describing the Testudinata, which summarizes all the world's turtles, living and extinct, illustrated by forty plates by Jane S. Bell, James de Carle Sowerby and

Edward Lear Edward Lear (12 May 1812 – 29 January 1888) was an English artist, illustrator, musician, author and poet, who is known mostly for his literary nonsense in poetry and prose and especially his limerick (poetry), limericks, a form he popularised. ...

. It was first defined in the modern sense by Joyce and colleagues in 2004. While the ancestral condition for the clade is thought to be terrestrial, members of the subclade Mesochelydia, which contains almost all known testudinatans from the Jurassic onwards, are thought to be ancestrally aquatic.

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