I believe Loggerheads and about half the size of Razorbacks and a much flatter shell than a razorback . I think Razorbacks look like Trojans . I'm sure there are more " experts " in this forum that can give you specifics on the two species. Both are very cool species and stay small . The more I look at mud and musks turtles the more I want ! Who said you can't have too many turtles !!!!