EARLY TO MIDDLE MIOCENE TURTLES FROM THE NORTHERNMOST TIP OF SOUTH AMERICA: GIANT TESTUDINIDS, CHELIDS, AND PODOCNEMIDIDS FROM THE CASTILLETES FORMATION, COLOMBIA 1 Senckenberg Museum, Paleoherpetology, 603025 Frankfurt, Germany. 2 Smithsonian Tropical Research Institute, Balboa, Ancon, Panama. EDWIN CADENA 1,2 CARLOS JARAMILLO 2 Submitted: September 29 th , 2014 - Accepted: November 10 th , 2014 To cite this article: Edwin Cadena and Carlos Jaramillo (2015). Early to middle Miocene turtles from the north- ernmost tip of South America: giant testudinids, chelids, and podocnemidids from the Castilletes Formation, Colombia. Ameghiniana 52: 188–203. To link to this article: http://dx.doi.org/10.5710/AMGH.10.11.2014.2835 PLEASE SCROLL DOWN FOR ARTICLE Also appearing in this issue: Diverse assemblage of large body sized turtles from the early–middle Miocene tropical South America. Exceptional braincase preservation in an acient megalonychid sloth from the Miocene of Patagonia. Marine and terrestrial palynomorphs and the Silurian–Devonian age of marine deposits of western Argentina.