The Mysterious Creature

S/He was looking, and I'm sure - also sniffing, me up, although I could not see his stiff nostrils moving, but could feel the air moving through them. Looking and sniffing, I was ready to face him/her, with camera pointed to get her/his picture in full and uncover its real face but then s/he, uncooperatively was only looking as only his/her big eyes remained above the water before it disappeared in the depths.

If someone can identify it - please!! (ID-ed already...)
I'm dying of curiosity to know what it was. It's not a gathor. Behind the head there is some part that looks like a big snake body, below (the head) there was some construction resembling turtle (but it's not a turtle's face?).

Did I encounter the monster of Everglades/South Florida?
Probably can use that to explain the ripped off side mirror to my rental car company (which "loosing" actually involved high speed and not so sane decissions which I don't want to elaborate on right now and here).

PS: it's actually Florida Softshell turtle Apalone ferox - even with these unbelievable for turtle nostrils, as Cindy helpfully pointed out (see comment). Thank you Cindy for taking the mystery out of my mysterious creature encounter.