Hydromedusa

Hydromedusa is a turtle genus in the family Chelidae, commonly known as the South American snake-necked turtles. They are quite closely related to the South American side-necked swamp turtles (Acanthochelys) and the snake-necked turtles of the Australian-Melanesian region (Chelodina), but less closely to the spine-necked river turtles of South America (Podocnemididae) which belong to a more modern lineage of Pleurodira.

Species
This genus contains the following extant and fossil species:
 * Brazilian snake-necked turtle, Cágado da Serra, Hydromedusa maximiliani
 * Argentine snake-necked turtle, Cágado pescoço de cobra, Hydromedusa tectifera
 * Hydromedusa casamayorensis De la Fuente & Bona 2002, Salamanca and Sarmiento Formations, Argentina