Sandownidae

Sandownidae is a family of extinct turtles from the Cretaceous and Paleogene of Eurasia. The family is defined as all taxa closer to the type genus Sandownia than to Pelomedusa, Testudo, Solnhofia, Eurysternum, Plesiochelys, Thalassemys or Protostega, a definition that encompasses the previous concept of the clade while also excluding it from being synonymous with other clades of modern or extinct marine turtles. Sandownidae may be within the larger clade Angolachelonia, defined as inclusive of Angolachelys and Solnhofia, sister to the entirely Late Jurassic marine group Thalassochelydia, although the concepts of the clades may shift with further phylogenetic analysis, the one below representative of the 2018 study by Evers and Benson.[1]

Testudinata	basal stem-group turtles       Meiolaniformes       Paracryptodira       Xinjiangchelyidae       Sinemydidae/Macrobaenidae     Testudines modern turtles   Angolachelonia   Thalassochelydia   Sandownidae   Brachyopsemys       Leyvachelys     Sandownia

Sandownidae Temporal range: Cretaceous to Paleogene
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	Testudines
Suborder:	Cryptodira
Infraorder:	Eucryptodira
Family:	†Sandownidae Tong & Meylan, 2013
Genera[1]
Angolachelys Brachopsemys Leyvachelys Sandownia

References

1. Evers, S.W.; Benson, R.B.J. (2018). "A new phylogenetic hypothesis of turtles with implications for the timing and number of evolutionary transitions to marine lifestyles in the group". Palaeontology. 62 (2): 93–134. doi:10.1111/pala.12384.