Faunistics and zoogeographical overview of the Mediterranean and Black Sea marine Gastrotricha

Biogeographia vol. XXIV - 2003 (Printed October, 31st 2003) Marine biogeography of the Mediterranean Sea: patterns and dynamics of biodiversity Faunistics and zoogeographical overview of the Mediterranean and Black Sea marine Gastrotricha M. ANTONIO TODARO*, LUCIA MATINATO**, MARIA BALSAMO***, PAOLO TONGIORGI** *Dz'pzzrrz'mem‘o di Bio/ogirz /lnimzzle, Uni:/ersitiz (ii Marian/1 E Reggio Emilirz, Vizz Czzmpi 213/cl’, [~41 I 00 Madcna (Juli)/),' e—mzzz'/: todzzro. zzntonio @zmimo. it **Dzj7zzrti7neI2to di Scierzze Agnzrie, Urziz/erritiz di Marlena e Reggia Emilia, Via Kennmfiz 17, 142100 Reggie Emz'lz'zz (Italy) ***[5tz'tLiz‘0 di Scimze Maifblogic/ye, Universitfz di Ureirzo, Via Oddi 21, I-61029 M~bz'no (Italy) Key words: Gastrotrichs, Biogeography, Meiofauna, Taxonomy, Mediterranean Sea, Black Sea. SUMMARY The paper provides an updated overview of the knowledge regarding the marine gastrotrich fauna of 10 Mediterranean and 2 Black Sea countries. Taxonomic account and species distribution come from published records, including electronically disseminated information, as well as original data from 18 localities (16 western and 2 levantine), investigated by the authors between 1990 and 2002. Since the description of the first marine Mediterranean gastrotrich, Hera)/zlzzijir izgzzm Claparede, 1867, discovered in the Gulf of Naples (Italy), 273 additional species, from 417 locations have been recorded in the basin so far. Of the gastrotrichs found, 143 species, in 24 genera and 6 families, belong to the order Macrodasyida and 131 species, in 11 genera and 3 families, belong to the order Chaetonotida; these statistics include several species as yet not described. The number of species per location is variable, ranging from 1—37, with a global mean of 8.041” 6.69 spp/location. Egypt and Israel show mean values well above the average, with 12.8 and 10.8 spp/loc. respectively, whereas mean values for Algeria, Tunisia, Bulgaria, Croatia, and France are below average (1— 5.43 spp / location); data For Cyprus, Greece, Romania and Italy are within the average value. Arttzzr/Jorlzzrys (Ictz/mtm‘, recorded in 28% of the investigated locations is the most Frequently found macrodasyidan; Htz/it/Jzzetmzatur am/zfi'r, also recorded in 28% of the investigated localities, is the most common chaetonotidan. Data analysis indicated substantial differences among countries, regarding sampling effort and, consequently, faunistic knowledge. In comparison with the generally good information concerning the Italian fauna (177 species from 246 localities), gastrotrichs from other Mediterranean nations are much less known; along with Italy, only few other Nations have been investigated to a sufficient extent (i.e., Greece: 44 sampled localities, 77 recorded species; France: 37 L, 70 spp; Egypt: 28 L, 81 spp; Israel: 15 L, 55 spp; Cyprus: 9 L, 41 spp), whereas investigation carried out in several other countries can be considered, to a variable degree, incomplete (i.e., Algeria: 16 investigated localities and 11 species found; Romania: 7 L, 30 spp; Tunisia: 5 L, 2 spp; Bulgaria: 3 L, 11 spp; Croatia: 1 L, 12 spp, Spain: 1 L, 3 sp, Malta; 2L, 2 spp.), or nil (e.g., Morocco, Libya, Turkey, Albania). All marine gastrotrich Families and most marine genera have representatives in the Mediterranean Fauna, notable absences regard the genera Demzoz/zzryr, Dirzadmjyr, Plzzizat/rziyx, Prostabucttzntizl and perhaps Prezzzfart/1‘brz71e[/zz; on the other hand representatives of two genera, En2_ytI'mji: and Dezzdmpar/01:1, are unknown elsewhere in the world except the western Mediterranean. At species level, about 140 taxa have so Far been found only in the Mediterranean area, whereas the