would be to find a copy of Kluge's paper and read it. Mostly it is a lot of analysis of characters, but the section where he lumps bottae, trivirgata, and reinhardtii into one genus (Charina) is short and easy to understand. And by easy to understand, I mean his reasoning is well layed out, not that it is necessarily logical!
Read what Kluge says and why he thinks the three species should be in one genus and come to your own conclusion.
And then ask yourself what happens if there are two species of Rubber Boas (bottae and umbratica) and two or more species of Rosies. Sort of confounds the basis for his lumping them all into Charina, IMHO.