Hlákreget

The Hlákreget was an archaic relative of the alligator that had survived in some of the northernmost parts of Middle-Earth, such as the Sinking Plain.It had a relatively short snout and could evolve into a length of up to 19 ft.It survived only in sweetwater and in contrast to other Carchadils and Assangar it had plump fins instead of feet and a rather fish-like tail, making it a formidable swimmer.

Notes:
The Hlákreget is vaguely based on the prehistoric Dakosaurus.