The River Lizards, as they have come to be known, are a genus of small theropod dinosaur. Their exact evolutionary history is not known at the current time, although a veriety of primitive ornithomimosaur similar to Pelecanimimus or Harpymimus is the most widely accepted theory. Other suggestions have been made that they are perhaps descended from a member of the Troodontidae, or Dromaeosauridae families.
Both of these models can easily be combined into a description of one kind of "Minidinosaur" and the size given for the "River Liz" matches the "Mountain Boomer" male. In fact there is no reason to make the size differences into sex differences rather than growth stages. The "River Liz" head should similarly be shortened and roundish, and the coloration of both being in basically a green background shading to gray in parts like the belly, overlaind by large irregular brown bands or splotches. The back has a sort of a crest on it and there may be horn-like structures on the head. All of this is in agreement with the actual reports.