It seems this is a work in progress. Since it's a big description, I'll come back later for more feedback.
I recommend using GIMP to enhance contrast, to make darker, more distinct lines. Unless these organisms are transparent and against a very uniform or stylized background of purple/purplish pink flora, I recommend coloring within the lines with their true coloration. That is best done after you darken the lines, because then you can use the paint bucket tool.
The front claws look drastically different from its ancestor's, if they're drawn at all. I recommend drawing on the front claws, or, if they have fused, thick, horse-like toenails they walk on, making that more clear in the art.
I'm not sure how plausible it is they would walk on extensions of their elbows.