A MULTIDISCIPLINARY CONTRIBUTION TO THE ILYOCYPRIS PUZZLE

Ilyocypris Brady & Norman, 1889 is a widespread freshwater ostracod genus that includes many living and fossil species (34 living species according to MARTENS & SAVATENALINTON, 2011; 28 living species according to KARANOVIC & LEE, 2013; around 190 fossil species according to KEMPF, 1980; 1997). The identification of Ilyocypris species is based on the soft parts and the valves characteristics of adult specimens (MEISCH, 2000). VAN HARTEN (1979: p.72) was the first to recognise the diagnostic value of the “marginal ripplets” located on the postero-ventral internal marginal zone of left valves. Such features, when preserved, have been regarded as a taxonomic speciesspecific character useful particularly to palaeontologists for the distinction of the most common Ilyocypris species, (JANZ, 1994). Another diagnostic feature of the carapace is the presence/absence of tubercles and spines in some species. Non-tuberculated and tuberculated specimens of I. bradyi and I. gibba and many transitional forms between these end members are often found in shells of I. gibba (VAN HARTEN, 1979; MEISCH, 1988, 2000; YANG et al., 2002). Although the occurrence of tubercles has been supposed to be environmentally cued (ANADÓN et al., 1986; YANG et al., 2002), ornamentation is still considered an important character for species identification (MEISCH, 2000; SYLVESTER BRADLEY & KEMPF, 1979).Our research aims to test the taxonomic significance of the carapace characteristics through the examination of specimens unambiguously identified on the basis of their soft part morphology according to Meisch (2000), in order to provide useful keys for the identification of Ilyocypris shells in fossil assemblages. We analysed adult valves of living Ilyocypris species collected in Italy, namely: Ilyocypris bradyi (18 carapaces), I. decipiens (c. 7), I. gibba (c. 17), I. inermis (c. 14) and I. monstrifica (c. 8).