Not sure if the leaked Pokemon images will turn out to be legitimate or not.
In my opinion the images do look like authentic Pokemon Company designs/art - I had the same feeling with leaked Serperior images back in the day and that gut feel turned out to be a good call. Of course they could still turn out to be very good hoax images.
Also it's supposed to be a Psychic/Water type. Other than that and the rear flippers it's a very generic-looking dolphin.
EDIT: Turns out it's most likely a fakemon. Nevermind.
Pokemon ™ and © The Pokemon Company
Artwork © David Nathan Dawkins.