Turtles from the families Pelomedusidae and Podocnemididae belong to the suborder Pleurodira. Pleurodira are recognizable from the suborder of Cryptodira by the way they hide their necks. Pleurodira turtles hide their head by folding the neck in a horizontal plane, while turtles from the Cryptodira withdraw their heads in a vertical plane.
Another feature to tell a Pleurodira from a Cryptodira is the presence of an intergular scute on the plastron which is not present with Cryptodira turtles. Pleurodira also have their pelvis fused to the plastron, a feature not seen in Cryptodira.
Pelomedusidae and Podocnemididae are separable from Chelidae, the other family of present day Pleurodira, by the presence of mesoplastral bones, which also are lacking in all Cryptodira.
Together with the extinct families Araripemydidae, Euraxemydidae and Bothremydidae, the Pelomedusidae and Podocnemididae form the hyperfamily Pelomedusoides. The history of this hyperfamily dates back to the early Cretaceous. The oldest known fossil Pelusios is Pelusios rusingae. The fossil history of Pelomedusa is quite poor, probably due to the arid environment where they normally occur. The fossil record of Podocnemis, Erymnochelys and Peltocephalus is quite rich.
Though Pleurodira are often considered primitive when compared to Cryptodira, recent research has shown immense diversity in skull morphology, especially within Bothremydidae. Interestingly, recent fossil evidence shows that Bothremydidae were found in both marine and freshwater environments.
However, we don’t wish to go very deep into the families Araripemydidae, Euraxemydidae and Bothremydidae, as this is done in an excellent way by Dr. Eugene S. Gaffney on his own site: Phylogeny of Turtles (http://research.amnh.org/users/esg).
We would like to place a complete as possible list of all known Pelomedusoides turtles at present (late 2007), extant and extinct. The list is made in an alphabetical- and family sequence and thus does not reflect the true relationship within the families regarding tribes or groups.
Though the taxonomic arrangement of the extinct families Araripemydidae, Euraxemydidae and Bothremydidae is cleared up by Gaffney et al.(2006), the taxonomic arrangement of the extinct Podocnemididae still remains puzzled.
With this list, we hope to encourage the reader to search on his own for more info if he or she wishes to.
† = extinct species
Araripemydidae:
†Araripemys barretoi (Price, 1973)
Bothremydidae:
†Acleistochelys maliensis (Gaffney, Roberts, Sissoko, Bouaré, Tapanila & O’Leary, 2007)
†Araiochelys hirayama (Gaffney, Tong & Meylan, 2006)
†Arenila krebsi (Lapparent de Broin & Werner, 1998)
†Azabbaremys moragjonesi (Gaffney, Moody & Walker, 2001)
†Bothremys arabicus (Zalmout, Mustafa & Wilson, 2005)
†Bothremys cooki (Leidy, 1865)
†Bothremys kellyi (Gaffney, Tong & Meylan, 2006)
†Bothremys maghrebiana (Gaffney, Tong & Meylan, 2006)
†Cearachelys placidoi (Gaffney, de Almeida Campos & Hirayama, 2001)
†Chedighaii barberi (Schmidt, 1940)
†Chedighaii hutchisoni (Gaffney, Tong & Meylan, 2006)
†Elochelys convenarum (Laurent, Tong & Claude, 2002)
†Elochelys perfecta (Nopcsa, 1931)
†Foxemys mechinorum (Tong, Gaffney & Buffetaut, 1998)
†Galianemys emringeri (Gaffney, Tong & Meylan, 2002)
†Galianemys whitei (Gaffney, Tong & Meylan, 2002)
†Kurmademys kallamedensis (Gaffney, Chatterjee & Rudra, 2001)
†Labrostochelys galkini (Gaffney, Tong & Meylan, 2006)
†Nigeremys gigantea (Bergounioux & Crouzel, 1968)
†Phosphatochelys tedfordi (Gaffney & Tong, 2003)
†Polysternon atlanticum (Lapparent de Broin & Murelaga, 1996)
†Polysternon provinciale (Matheron, 1869)
†Rhothonemys brinkmani (Gaffney, Tong & Meylan, 2006)
†Rosasia soutoi (Carrington da Costa, 1940)
†Sankuchemys sethnai (Gaffney, Sahni, Schleich, Singh & Srivastava, 2003)
†Taphrosphys congolensis (Dollo, 1913)
†Taphrosphys ippolitoi (Gaffney, Tong & Meylan, 2006)
†Taphrosphys sulcatus (Leidy, 1856)
†Ummulisani rutgersensis (Gaffney, Tong & Meylan, 2006)
†Zolhafah bella (Lapparent de Broin & Werner, 1998)
Euraxemydidae:
† Caririemys violetae (Oliveira and Kellner, 2007)
†Dirqadim schaefferi (Gaffney, Tong & Meylan, 2006)
†Euraxemys essweini (Gaffney, Tong & Meylan, 2006)
Pelomedusidae:
Pelomedusa subrufa (Lacepède, 1788)
Pelusios adansonii (Schweigger, 1812)
Pelusios bechuanicus (FitzSimons, 1932)
Pelusios broadleyi (Bour, 1986)
Pelusios carinatus (Laurent, 1956)
Pelusios castaneus (Schweigger, 1812)
Pelusios castanoides (Hewitt, 1931)
Pelusios chapini (Laurent, 1965)
Pelusios cupulatta (Bour & Maran, 2003)
Pelusios gabonensis (Duméril, 1856)
Pelusios marani (Bour, 2000)
Pelusios nanus (Laurent, 1956)
Pelusios niger (Duméril & Bibron, 1835)
Pelusios rhodesianus (Hewitt, 1927)
†Pelusios rusingae (Williams, 1954)
Pelusios seychellensis (Siebenrock, 1906)
Pelusios sinuatus (Smith, 1838)
Pelusios subniger (Lacepède, 1788)
Pelusios upembae (Broadley, 1981)
Pelusios williamsi (Laurent, 1965)
Podocnemididae:
†Bairdemys hartsteini (Gaffney & Wood, 2002)
†Bairdemys venezuelensis (Wood & Díaz de Gamero, 1971)
†Bauruemys brasiliensis (Staesche, 1937)
†Bauruemys elegans (Suárez, 1969)
†Brasilemys josei (Lapparent de Broin, 2000)
†Cambaremys langertoni (França & Langer, 2005)
†Dacquemys fajumensis (Andrews, 1903)
†Dacquemys paleomorpha (Williams, 1954)
†Erymnochelys aegyptiaca (Andrews, 1900)
Erymnochelys madagascariensis (Grandidier, 1867)
†Hamadachelys escuillei (Tong & Buffenaut, 1996)
†Kenyemys williamsi (Wood, 1983)
†Neochelys arenarum (Broin, 1977)
Peltocephalus dumeriliana (Schweigger, 1812)
† Podocnemis bassleri (Williams, 1956)
Podocnemis erythrocephala (Spix, 1824)
Podocnemis expansa (Schweigger, 1812)
Podocnemis lewyana (Duméril, 1852)
†Podocnemis negrii (Carvalho, Bocquentin & Broin, 2002)
Podocnemis sextuberculata (Cornalia, 1849)
Podocnemis unifilis (Schweigger, 1812)
Podocnemis vogli (Müller, 1935)
†Portezueloemys patagonica (De La Fuente, 2003)
†Roxochelys harrisi (Pacheco, 1913)
†Roxochelys vilavilensis (Broin, 1971)
†Roxochelys wanderleyi (Price, 1953)
†Shweboemys antiqua (Andrews, 1903)
†Shweboemys bramlyi
†Shweboemys gaffneyi (Wood, 1970)
†Shweboemys pilgrimi
†Shweboemys pisdurensis (Jain, 1977)
†Stereogenys cromeri (Andrews, 1901)
†Stereogenys libyca (Andrews, 1906)
†Stupendemys geographicus (Wood, 1976)
†Stupendemys souzai (Bocquentin & Melo, 2006)
†Uberamemys
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