Congruence and conflict in Albinaria (Gastropoda, Clausiliidae). A review of morphological and molecular phylogenetic approaches

Albinaria is a pulmonate genus distributed around the north-eastern coasts of the Mediterranean, exhibiting a high degree of morphological and molecular differentiation, especially in southern Greece and in the external insular Hellenic arc. As a consequence, traditional taxonomists have named more than 200 taxa (species and subspecies). Three major revisions indicate the complexity of this taxon and several authors have questioned the validity of its current taxonomy. Recently, the use of both molecular and morphological phylogenetic approaches, on similar taxa sets, showed contradictory results. In cases where the palaeogeographic history of the area occupied by the studied taxa was unambiguous and the terminal taxa studied were relatively few, morphological and molecular results almost coincided. However, in cases where landscape modifications were drastic and unstable, and the number of terminal taxa was high, these approaches came to conflicting conclusions. The above situation indicates the methodological limitations of each approach and implies that evolutionary processes within Albinaria do not follow a stable and uniform (spatial and temporal) pattern. In the present contribution the above mentioned contradictory results and methodological shortcomings are discussed, and a re-evaluation of characters and is proposed. I suggest that interpretation of results must be phylogenetically consistent and only monophyletic taxa should be accepted. Additionally, rate-dependent clustering or rooting methods which resulted in the more unresolved, unstable and unjustified inter- and intra-specific relations should be avoided. Unresolved, unstable and conflicting inter- and intra- specific topologies implied that certain characters must be re-evaluated or avoided in phylogenetic analyses for Albinaria. Such characters are: morphometrics, genitalia, certain highly homoplasious shell characters or allozyme loci, and non-conservative or ambiguously aligned genes.