Distinguishing characteristics: long streamlined animals with a thick tapered tail and short legs, wide, rounded head, small ears, and nostrils that can be closed underwater. long thick whiskers. they are dark brown to black above a ligther color ventrally. throat and cheeks are usually a golden. The feet have claws and are completely webbed.
- North-West Atlantic Ocean species (NWARMS) http://www.marinespecies.org/aphia.php?p=sourcedetails&id=2901