Messinian fossil fish of the Mediterranean
Abstract Analysis of the ecological characteristics of the Messinian, Lower Pliocene and present-day ichthyofauna of the Mediterranean basin reveals various data which are consistent with the hypothesis of the desiccation of the Mediterranean. In the numerous fish-bed localities of the Lower and Middle Messinian, where the sequence is complete, the lower levels contain a rich ichthyofauna with exclusively marine species. Amongst these species are meso- and bathypelagic forms. The marine sequences are overlain conformably by evaporitic levels which contain an ichthyofauna dominated by euryhaline forms, and also containing very rare freshwater and marine forms. As far as we know, there are no fish-bed localities which can be referred to the Upper Messinian. 3n the Lower Pliocene, the ichthyofauna found in Liguria, Emilia, Sardinia and Sicily, consists exclusively of marine species; again meso- and bathypelagic forms are present. The ichthyofauna of the Lower Pliocene seems to consist solely of the Mediterranean-Atlantic type. In Europe and Anatolia, the pre-Messinian freshwater fish beds indicate a population with an East Asiatic or Siberian origin whilst in North Africa the species which have been noted are of African origin. At present, in the freshwater of Algeria, Tunisia and Morocco, there are fish of European origins. The ichthyofauna now living in the Mediterranean is characterized, at a generic level, by a limited number of endemic forms; several of these are euryhaline forms, which are also found in the evaporitic levels of the Lower and Middle Messinian. This observation points to a recent population of the Mediterranean by exclusively marine forms, whilst those with an euryhaline character could have evolved in loco. The fossil genus Pachylebias is to be considered synonymous with the present genus Aphanius.