According to the search results, the species of the Teenage Mutant Ninja Turtles (TMNT) varies depending on the version of the franchise. In the 2018-2020 TV series "Rise of the Teenage Mutant Ninja Turtles," all four turtles are explicitly different species of turtles: Raphael is an alligator snapping turtle, Leonardo is a red-eared slider turtle, Donatello is a softshell turtle, and Michelangelo is a box turtle. In the 2012 incarnation, Donatello theorizes that they were diamondback terrapins. In the 1990 comic, it was stated that they were red-eared sliders. In the 2003 TV series, they were depicted as being green sea turtles. In conclusion, the species of the TMNT varies depending on the version of the franchise.