Conventional and fundamental problems in the delimitation of genera from a phylogenetic point of view

What will be considered as problems in the delimitation of genera and what as their solutions depends upon one’s views. The same holds for qualifying a particular problem as conventional or fundamental. Thus, choices have to be made. If a scientific status is claimed for systematics, theory should be involved since one cannot speak of science if explanatory theories are lacking. I opt, for the time being, for evolutionary theory as the most relevant theory for systematics, and, in my opinion, the phylogenetic school (Hennig, 1966; Wiley, 1981) offers the best evolutionary interpretation of classifications. Of course, other views are possible, but 1 would like to remind those who are perhaps irritated by my choice for these ‘fashionable’ and disturbing views that they are by no means new. In his book Systematics and the Origin of Species (first printed in 1942) Mayr wrote: “The theory of evolution solved the puzzle of the high degree of perfection of the natural system in a manner that was as simple as it was satisfactory: The organisms of a ‘natural’ systematic category agree with one another in so many characteristics because they are descendants of one common ancestor! The natural system became a ‘phylogenetic’ system.” (Mayr, 1964: 276), “a phylogenetic system has two advantages: first, it is the only system that has a sound theoretical basis (something the natural philosophers of the early nineteenth century looked for in vain)..(Mayr, 1964: 276). Unfortunately, Mayr wavered between morphological gaps and phylogenetic relations and thus he made ‘evolutionary systematics’, internally inconsistent.