One of the most crucial questions of twenty-first century systematic biology deals with the determination of the real number of living species currently sharing the Earth with us (Cracraft 2002); answers vary widely, but commonly range between 3 and 100 million (see, for example, Stork 1997 or May 2002 and references therein). However, in terms of completeness and correctness, our current inventory of living species is certainly unsatisfactory (Dubois 2003), as the total number of species described so far is known to correspond to only a very small fraction of the Earth´s biodiversity. Indeed, large numbers of species remain to be discovered, primarily insects, small invertebrates and, above all, microorganisms (Chevalier et al. 1997). On the other hand, this gap of knowledge regarding the magnitude of the Earth´s biodiversity limits our capacity to properly manage the world´s biotic resources and conserve biological diversity in this so-called Century of Extinctions (Dubois 2003): the current biodiversity crisis is wiping out a significant fraction of living species at an alarming rate and, sadly, an unknown number of species is being forever lost before being discovered, described, and named. Likewise, conservation priorities are clearly constrained by our limited knowledge of the total biodiversity (Dubois 2003, Scotland et al. 2003).