World Congress of Malacology Antwerp ... - Unitas Malacologica

done. The correlation between mollusc species and environmental factors was revealed using
Canonic Correspondence Analysis.
Habitat selection of limpet (Patella ssp.) species in the tidal zone at the Adriatic Sea
Nyilas, István; Simon, Viktor
Department of Evolutionary Zoology, University of Debrecen, Egyetem tér 1, H-4010 Debrecen,
Hungary,
Email: steve@tigris.klte.hu
Limpets (Patellidae) are important grazing molluscs in the tidal zone at the Adriatic Sea. Our studies
were carried out in 18 sample areas along the east coast of the Adriatic Sea between 2004-2007. The
aim of our investigations was to reveal the abundance and dominance conditions of the limpet species
occuring along this coast, as well as metrically characterize the populations. The following species
have been found: Patella coerulea, P. caerulea f. subplana, P. rustica, P. ulyssiponensis.
Multivariable statistical methods have been used to find correlation between the Patella species and
environmental factors.
18 sample sites were chosen in a way to cover various habitat types, including two islands (Krk,
Murter). The conditions of occurrence of the Patella fauna of the islands have been compared to
those of on the coastline of the Balkan Peninsula. Both natural limestone and anthropogenic concrete
bases were examined in the course of sampling.
Quadrat method was used to measure the abundance of limpets. Environmentaly limiting factors were
examined, including physical (e.g. the quality of base surface, tidal exposure time, water level and
temperature, depth of occurrence, slope), chemical (e.g. pH, salinity, conductivity, base rock, the
chemical composition of the water) and biological factors (e.g. potential food supply, other sea
animals).
Patella coerulea was found in each sampling site in the biggest numbers. Significantly bigger
individuals lived on concrete than natural limestone base. Concrete is smoother, adhesion to its more
even surface is favourable for the animal, whereas the uneven surface of limestone provides less
favourable conditions. At times of low tide, tight attachment tends to be essential for survival. The
size of Patella species seems to decrease in more extreme habitats. On the basis of present
nomenclature, P. coerulea f. subplana occurred in the infralittoral zone. Patella rustica mainly occurs
on vertical surface exposed to rolling sea in the supralittoral fringe, while Patella ulyssiponensis is
typical in the infralittoral fringe. Food at the examined sites was abundant, so distributional
differences are primarily due to environmental factors. Patella species and their habitats were
ordinated using Canonic Correspondence Analysis (CCA) and further correlation with environmental
factors was assessed.
Species delineation and genetic variation in the genus Hiatella (Bivalvia, Heterodonta)
Oberlechner, Miriam; Steiner, Gerhard
University of Vienna, Faculty of life sciences, Center of Zoology, Department of Evolutionary
Biology, Molecular Phylogenetics, Althanstrasse 14, A-1090 Vienna, Austria,
Email: miriam.oberlechner@gmx.at; Gerhard.Steiner@univie.ac.at
Hiatella is a common bivalve genus in the European rocky subtidal. It is not clear, however, how
many species are represented due to the high plasticity in shell form and the resulting problems in
species delineation. They live at depths down to 60 m, either in rock crevices as bioeroders, nestling
in kelp holdfasts, or within sponges. Shell morphology is often influenced by the shape of the
crevices and eroded during boring. We here present the preliminary results of a molecular
investigation of Hiatella from the Mediterranean, testing taxonomical and ecological concepts. We
collected Hiatella specimens in different habitats of the Mediterranean, including the North Adriatic
Sea (Croatia), the Ligurian Sea (Italy), and the south coasts of Spain and Portugal. We used a
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