Turtles breathe in two ways. First, they employ buccal pumping, pulling air into their mouths, then pushing it into their lungs via oscillations of the floor of the throat. Secondly, when the abdominal muscles that cover the posterior opening of the shell contract, the internal volume of the shell increases, drawing air into the lungs, allowing these muscles to function in much the same way as the mammalian diaphragm.
Many species have a pair of sacs (bursae) opening off the cloaca (combined digestive and urogenital chamber). These are heavily vascularized to facilitate the uptake of oxygen.
Do you think is a powerful evolution feature?