Americhelydia is a clade of turtles that consists of sea turtles, snapping turtles, the Central American river turtle and mud turtles, supported by several lines of molecular work.Chandler, C. H., & Janzen, F. J. (2009). The phylogenetic position of the snapping turtles (Chelydridae) based on nucleotide sequence data. Copeia, 2009(2), 209-213.Barley, A. J., Spinks, P. Q., Thomson, R. C., & Shaffer, H. B. (2010). Fourteen nuclear genes provide phylogenetic resolution for difficult nodes in the turtle tree of life. Molecular Phylogenetics and Evolution, 55(3), 1189-1194.Crawford, N. G., Parham, J. F., Sellas, A. B., Faircloth, B. C., Glenn, T. C., Papenfuss, T. J., ... & Simison, W. B. (2015). A phylogenomic analysis of turtles. Molecular Phylogenetics and Evolution, 83, 250-257. Prior to these studies some morphological and developmental work have considered sea turtles to be basal members of Cryptodira and kinosternids related to the trionychians in the clade Trionychoidea.Joyce, W. G. (2007). Phylogenetic relationships of Mesozoic turtles. Bulletin of the Peabody Museum of Natural History, 48(1), 3-102.Werneburg, I., & Sánchez-Villagra, M. R. (2009). Timing of organogenesis support basal position of turtles in the amniote tree of life. BMC Evolutionary Biology, 9(1), 82. Americhelydia and Testudinoidea, both clades within Durocryptodira (hardshell turtles), split apart during the early Cretaceous.
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