Pantestudines

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 member of Pantestudines (i.e. a stem-turtle). It is the only known species in the genus Odontochelys and the family Odontochelyidae.

Pantestudines or Pan-Testudines is the proposed group of all 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 extinct relatives (also known as stem-turtles). Pantestudines with a complete shell are placed in the clade Testudinata.

Pappochelys (παπποχέλυς [πάππος (grandfather) + χέλυς (turtle)] meaning "grandfather turtle" in Greek) is an extinct genus of diapsid reptile possibly related to turtles. The genus contains only one species, Pappochelys rosinae, from the Middle Triassic of Germany, which was named by paleontologists and Hans-Dieter Sues in 2015. The discovery of Pappochelys provides strong support for the placement of turtles within Diapsida, a hypothesis that has long been suggested by molecular data, but never previously by the fossil record. It is morphologically intermediate between the definite stem-turtl

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.