biostudies-literatureUnknown142(1)Scheyer TMFossils of Cretaceous sea turtles adapted to an open marine lifestyle remain rare finds to date. Furthermore, the relationships between extant sea turtles, chelonioids, and other Mesozoic marine turtles are still contested, with one key species being <i>Santanachelys</i> <i>gaffneyi</i> Hirayama, 1998, long considered the earliest true sea turtle. The species is an Early Cretaceous member of <i>Protostegidae</i>, a controversial clade either placed within or closely related to <i>Chelonioidea</i> or, alternatively, along the stem lineage of hidden-neck turtles (<i>Cryptodira</i>) and representing an independent open marine radiation. <i>Santanachelys</i> <i>gaffneyi</i> is one of the most completely preserved early protostegids and is therefore critical for establishing the global phylogenSwiss journal of palaeontology6https://www.ebi.ac.uk/biostudies/studies/S-EPMC10163108biostudies-literatureA forged 'chimera' including the second specimen of the protostegid sea turtle <i>Santanachelys</i><i>gaffneyi</i> and shell parts of the pleurodire <i>Araripemys</i> from the Lower Cretaceous Santana Group of Brazil.PMC10163108Rabi MFalco LScheyer TMBastiaans DFerreira GSOliveira GRRomano PSRfalseA forged 'chimera' including the second specimen of the protostegid sea turtle <i>Santanachelys</i><i>gaffneyi</i> and shell parts of the pleurodire <i>Araripemys</i> from the Lower Cretaceous Santana Group of Brazil.Fossils of Cretaceous sea turtles adapted to an open marine lifestyle remain rare finds to date. Furthermore, the relationships between extant sea turtles, chelonioids, and other Mesozoic marine turtles are still contested, with one key species being <i>Santanachelys</i> <i>gaffneyi</i> Hirayama, 1998, long considered the earliest true sea turtle. The species is an Early Cretaceous member of <i>Protostegidae</i>, a controversial clade either placed within or closely related to <i>Chelonioidea</i> or, alternatively, along the stem lineage of hidden-neck turtles (<i>Cryptodira</i>) and representing an independent open marine radiation. <i>Santanachelys</i> <i>gaffneyi</i> is one of the most completely preserved early protostegids and is therefore critical for establishing the global phylogen2023-01-01T00:00:00Z20232025-04-22T04:10:45.262Z2024-11-20T21:52:20.836ZS-EPMC101631083716314310.1186/s13358-023-00271-9