creature art; lessons and offerings

As you know, I'm new to paleoart. I work in illustration, animation and concept. A series of weekly creature challenges at cgHub provoked me into writing here. Check out the jelly bubbled broad back here.
What's the difference between creature design and paleoart? At the worst of times, its a film creature that causes laughter instead of fear, because of its obvious inability to exist - or perhaps a life reconstruction that ignores the potential to fascinate an audience and instead opts for dried-out clinical presentation.
What do these disciplines share? Everything from a disciplined observation of anatomy and ecosystem to a imaginative yet responsible creativity in presenting fascinating creatures within a restrictive framework of either scientific knowledge or story plot.