World Congress of Malacology Antwerp ... - Unitas Malacologica

Chromosome numbers and chromosomal evolution in the land snail genus Arion (Gastropoda,
Pulmonata)
Colomba, Mariastella 1 ; Backeljau, Thierry 2,3 ; Gregorini, Armando 1 ; Jordaens, Kurt 3
1. University of Urbino ‘Carlo Bo’, Via Sasso 75, 61029 Urbino, Italy,
Email: m.colomba@uniurb.it; a.gregorini@uniurb.it
2. Royal Belgian Institute of Natural Sciences, Vautierstraat 29, B-1000 Brussels, Belgium,
Email: Thierry.Backeljau@naturalsciences.be
3. University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium,
Email: kurt.jordaens@ua.ac.be
The European terrestrial slug genus Arion Férussac, 1819 comprises about 30-50 currently
recognized species. We determined chromosome numbers in seven Arion species, viz. A. lusitanicus
(N=24), A. subfuscus (N=25), A. rufus (N=26), A. vulgaris (N=26), A. distinctus (N=28) and A.
circumscriptus (N=29). We also determined the chromosome number in three species of two related
taxa, viz. Geomalacus anguiformis and G. maculosus (both N=31) and Letourneuxia sp. (N=31). This
study confirms the previously reported chromosome numbers for Arion. It furthers supports the
current view that the Portuguese Arion lusitanicus is different from the non-Iberian ‘A. lusitanicus’
that should be referred to as A. vulgaris. Finally, the study suggests a close relationship between
Geomalacus and Letourneuxia. Haploid chromosome numbers N=27 and N=30 were not found.
Chromosome numbers were plotted onto a molecular phylogeny of the genus and the evolution of
chromosome numbers within the genus Arion will be discussed.
Late Glacial-Early Holocene environmental change at Favignana island (Sicily - Italy):
evidence from malacological records in prehistoric deposit
Colonese, A.C.; Lo Vetro, D.; Martini, F.
Dipartimento di Scienze dell’Antichità “G. Pasquali”, University of Firenze. Museo e Istituto
Fiorentino di Preistoria “P. Graziosi”, via S. Egidio 21, 50121, Firenze, Italy,
Email: colonese@unisi.it
The continental shelf is a complex environment where waves, tides, currents, input from the
continent and sea, and humans interplay through time and space. To understand the variability in this
past evironment (i.e., Late Quaternary) multidisciplinary approaches are required, in addition to
which archaeological archives in coastal zones may be of prime importance. This paper reports the
ecological and geochemical analyses of marine and continental molluscan shell remains from
prehistoric layers of Grotta d’Oriente, a coastal cave located on the Favignana island (37°55' N;
12°20' E - Sicily) and frequented by humans during the Late Glacial-Early Holocene. Anthropogenic
Late Glacial deposits are characterized by the abundant presence and high frequency of paralic
species (i.e., Pirenella conica (Blainville, 1826)) as well as by the presence of freshwater species
(i.e., Lymnaea (Galba) truncatula (Müller, 1774)), probably brought into the cave by humans with
aquatic plants. In contrast Early Holocenic deposits are instead characterized by the absence of
paralic species and the abundance of marine intertidal species (i.e., Osilinus turbinatus (von Born,
1778)), exploited by human communities. Freshwater species are even absent in these layers.
Ecological and statistical analysis shows evidence of a progressive transition from paralic to marine
environment between Late Glacial and Early Holocene and the human response to this abrupt change.
According to other records, this environmental transition results from both sea level rise and lower
freshwater budget during the formation of Favignana island and its separation from the island of
Sicily at this time. Oxygen isotopic composition of Eobania vermicolata (Müller, 1774, Gastropoda,
Pulmonata) indicates, in accordance with other records from the Mediterranean region, a dry to wet
climate transition between Late Glacial and Early Holocene. Results highlight the importance of
multidisciplinary approaches in fossil shell analysis with regards to ascertaining past environmental
changes and the human communities response.
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