Cool post!
I would say with reasonable confidence that it is a male! Those long claws are usually pretty recognizable in aquatic turtles; during mating season, males show their interest in females by tapping on their heads with their freakishly long claws. I haven't got a good video of that behavior yet, but maybe one day soon lol.
Cool! I didn't know how exactly to tell with turtles
Female turtles have a flat or convex bottom shell, whereas males have a concave one. It's quite logical of Mother Nature to design the males that way, if you think about it! :) Resteemed and followed!