Cetaceoid

Cetaceoid is a sapient species of cetacean that evolved from a prehistoric group of porpoises that grew much smarter. They are about the size of bottlenose dolphins and roughly weigh about the same. Since cetaceoids are fully aquatic, they solved the problem of not going onto land by developing their own advanced technologies (including robotic legs, etc) to allow them to live on land, not just in water. Unlike their ancestors, they are omnivorous, feeding on not just fish, but also on the same food as other sapient species.