Evolution,actuality and species concept: a need for a palaeontological tool

Species concept was developed to fit neontological necessities in ordering biological variability. Transversal (horizontal, synchronic) taxonomy shows hierarchical requirements quite different from those involved in longitudinal (vertical, diachronic) classifications. Furthermore, limitations within the species concept itself make it scarcely available in many paleontological contexts. Classical species definitions are often limited by theoretic and logic constraints, that are seldom available to describe practical situations. Morphology is an uncertain source of phylogenetic information, but it is still the main ground of biological comparison for extinct populations. Therefore, efforts in species recognition should be devoted to making taxonomy a useful tool for communication. First, inferences in systematics have to be led upon the available information about characters and processes. If this information is missing or not developed, no detailed conclusions can be supported. Secondly, definitions should be sufficiently elastic and generalised to allow an adaptation to each different case-study. The final target is to synthesise actual evolutionary histories, and not biological potentialities.