" Science has developed a taxonomic system in which we all try to bring clarity in the genetic relationships by grouping the closest related entities in the same group, i.e. populations into species, species into genera, and genera into tribes/families. By placing trewavasae and fuelleborni in the same genus we indicate that they are closely related and we know these are two different species because often both can be found at the same locality. By adding two more species (of the same rank) to this genus one infers that at some point three or all four species can be found sympatric, which certainly is not the case. So, what is the advantage of splitting geographical variants into species? "
Classification: Taxonomy and phylogeny, Lake Malawi.