Biogeography of benthic marine Amphipods in Mediterranean Sea

Biogeographia vol. XXIV - 2003 (Printed October, 31st 2003) Marine biogeography of the Mediterranean Sea: patterns and dynamics of biodiversity Biogeography of benthic marine Amphipods in Mediterranean Sea DENISE BELLAN—SANTINI*, SAN DRO RUFFO** *Cem7qe :tqOce’tz7z0[0gie ale Mzzisei/le, Station Mzzrim‘ zl’Ena’ozm2e, UMR 6540 D1114/1R, Rue Bzztterie dc‘: Liam, 13007 Mzz7'5ei[/e ( France} **Mztseo Cit/ico [Ii Storizz Nzztumle, Lmzgtzdzge Pomz Vz'ztorz'tz 9, 37129 Verona (Italy) Key words: benthic Amphipods, Mediterranean Sea, biogeography. SUMMARY The fauna of Mediterranean amphipods includes 466 species, near 6% of the known world wide amphipod fauna. They constitute four major categories of geographical distribution: species common to Mediterranean and Atlantic (55%), indopaciflc probably lessepsiztn species (19%). cosmopolitan species (4.6%), mediterranean endemic species (385%). In consideration with these data. it is evident that it is a great affinity between Mediterranean fauna and the Atlantic one and that the level ofendemicity is very high. 95% of the whole species are present in the western bassin, 70% in the eastern and 53% in the Adriatic. Inside the group of the species common with Atlantic and Metliterranean Sea, 1 1°/o are exclusively mauritanian, 18.5% mauritanian—lusitanian, 20.5% lusitanian, 32% lusita.nian-boreal, 36.4% of the species have a large continued atlantic distribution and 12.2% a discontinuous distribution between the boreal and lusitanian regions. These boreo—mediterranean species are essentially bathyal. The analysis of species common I'D Atlantic and Mediterranean suggests different center of origin in the Atlantic and the Mediterranean. The supposedly lessepsian species (9) are essentially present in the eastern basin. Considering the historical population of the Mediterranean we consider the 10 endemic genera and the 12 genera common to Indopacilic and Mediterranean and absent in the Atlantic to be particularly important. The general conclusions of the biogeographic data on the amphipod Fauna confirm the complexity of the histoiy of the origin, from premessinian to actual, of the Mediterranean fauna. INTRODUCTION The present list of Mediterranean benthic amphipods is composed by 466 species, 15 more than in 1998 (Bellan—Santini and Ruffo, 1998). The 15 new species for the Mediterranean are: Autonoe azttzlzzuniczz Ruffo, Cartes and Sorbe, 1999, Longigzzmmzzrzts10/zzmzsizze Messana and Ruffo, 2001, H)/zzle micbe/z’m' Krapp-Schickel and Bousfield, 2002, Eriopisel/¢z mfii Marti and Villora-Moreno, 1996, Gzzmmzzrelltz gzz7qcz'zzz' Marti and Villora-Moreno, 1995, Qutzdrimzzerzz zzrzkzdne Krapp, Marti and Ruffo, 1996, Quczdrimzzertz durum Krapp, Marti and Ruffo, 1996, Qzttztlrimzzertz reveltzm Krapp, Matti and Ruffo, 1996, Bat/aymedon [o7zgz'r05trz's]au1ne, Cartes and Sorbe, 1998, Stenot/aoepieroptzn Krapp—Schickel, 1996, Stenoz‘/Joe maittirzzgortz Krapp-Schickel, 1996, Urot/706 /aesperizze Conradi,