World Congress of Malacology Antwerp ... - Unitas Malacologica

Caudofoveata (or Chaetodermomorpha) and Polyplacophora, generally regarded as the most basal
stemlines among the Mollusca, even if there is no consensus upon the relative position of the three
clades to each other and to the more derived conchiferan clades.
Here, the morphology of the nervous system of the solenogaster Wirenia argentea is presented based
on histological and immunocytochemical analyses using fluorescent markers against the
neurotransmitters serotonin and FMRF-amide, as well as acetylated α- tubulin, in combination with
confocal laser scanning microscopy. The results for W. argentea are compared to preliminary results
on other solenogaster species. The nervous system of solenogasters in general displays a distinct
tetraneury with fused cerebral ganglia, large pedal ganglia, and longitudinal nerve cords connected by
numerous fairly regularly spaced connectives and commissures. There is no indication of metamery,
though. FMRF-amidergic immunoreactivity is present in most compartments of the nervous system,
while serotonergic immunoreactivity appears to be restricted to the main nerve cords. Labeling with
acetylated α- tubulin depicts the entire nervous system and diverse ciliary structures, including the
specialized cilia of sensory cells.
Biodiversity of aplacophoran mollusks in the coastal area near Bergen, Norway
Todt, Christiane 1 ; Schander, Christoffer 1,2
1. University of Bergen, Department of Biology, Thormøhlensgate 55, P.O. Box 7800, N-5020
Bergen, Norway,
Email: Christiane.Todt@bio.uib.no
2. Centre for Geobiology, University of Bergen, Allégaten 41, 5007 Bergen, Norway,
Email: Christoffer.Schander@bio.uib.no
The Northern Scandinavian West coast is unique in that it comprises extremely diverse climate
regimes from temperate to arctic waters. In addition, in the fjord region deep-water species are found
in relatively shallow waters. Mollusks are an important integrative element of the benthic fauna
communities in Scandinavian coastal areas but research has largely been focused on the Bivalvia,
Gastropoda, and Cephalopoda. Much less is known about the worm-shaped aplacophoran classes
Solenogastres (Neomeniomorpha) and Caudofoveata (Chaetodermomorpha). These taxa are
considered to have a crucial position at the base of the phylogenetic tree of the Mollusca, but our
knowledge of the biology, geographical distribution, and biodiversity of these often small and
inconspicuous animals is still very limited. Worldwide, the total number of species described is about
240 for Solenogastres and 140 for Caudofoveata. From coastal waters of the Northern Atlantic Ocean
in the Bergen area (Western Norway) twelve species of Solenogastres and five species of
Caudofoveata were previously reported. Our intense collecting efforts of the last years showed that
the biodiversity of aplacophoran mollusks was considerably underestimated, especially concerning
the Solenogastres. In this poster we present an overview of the new and old findings and show the
great morphological variety and beauty of Western Norwegian aplacophoran mollusks.
Phylogeographical differentiation of Iberian populations of freshwater pearl mussel
(Margaritifera margaritifera) based on microsatellites data
Toledo, Carlos; Machordom, Annie; Araujo, Rafael
Museo Nacional de Ciencias Naturales (CSIC), José Gutiérrez Abascal 2. 28006, Madrid, Spain,
Email: carlostc@mncn.csic.es; annie@mncn.csic.es; rafael@mncn.csic.es.
Margaritifera margaritifera is a species of freshwater mussel critically endangered across its range,
making the development of conservation and management strategies a priority for this species. The
genetic structure and variability of Iberian populations were analysed based on 13 previously
published polymorphic microsatellites for 14 populations from different basins located in northwestern
Iberian Peninsula (previously studied using mtDNA). Preliminary analyses revealed
generally low levels of polymorphism with a heterozygote deficit at each locus. Despite this fact we
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