Pantanal swamp turtle
A. macrocephala is known from the upper Rio Mamoré drainage of central Bolivia, the Pantanal region and other swamplands of the upper Rio Paraguay drainage in southwestern Mato Grosso, Brazil, to the Chaco of Paraguay. Its range in Bolivia may be more extended.
This species is most closely related to Acanthochelys radiolata ; it includes Phrynops chacoensis. It inhabits marshes, swamps, and slow-flowing streams.