Alexander River, Israel, a couple of weeks ago:
Alongside Trionyx triunguis, Mauremys rivulata and - sadly but unsurprisingly - Trachemys scripta this odd looking specimen swam about.
It can't be Mauremys and it certainly isn't a typical Trachemys either, so what is it?
Some other species of released pet?
...or an old Trachemys with a darkened head and bleached carapace?