In mycology one will hear references to 'lumpers' and 'splitters' taxonomically. That is, do we lump these specimens together, or do we split them into difference groupings. When we look at the genetics, it has been the case that we find that those critters that appear similar may not be those that are related by genes/ evolution. And of course by "we" I mean the larger scientific community, not me and the mouse in my pocket. Oh wait, that's not a mouse it's a shrew. ;-)