World Congress of Malacology Antwerp ... - Unitas Malacologica

can be used as a marker of the sediment pollution. Moreover, the disease affect negative on
organisms physiological activity (respiration, reproduction) and total condition. The occurrence of
epizootics like neoplasia can be of a particular importance for the exploitation of aquacultures and
wild populations of bivalves.
Molluscan mito-genomics: chances and pitfalls in phylogenetics
Steiner, Gerhard; Dreyer, Hermann
University of Vienna, Faculty of life Sciences, Center of Zoology, Department of Evolutionary
Biology, Molecular Phylogenetics, Althanstr. 14, A-1090 Vienna, Austria,
Email: gerhard.steiner@univie.ac.at; hermann.dreyer@univie.ac.at
The use of complete mitochondrial (mt) genomes – their sequences and gene orders – has raised high
hopes of resolving important questions in molluscan phylogenetics. Yet, published data and analyses
reveal only a limited power of resolution and several obvious nonsense-clades. Why is that so? In
contrast to arthropods or vertebrates, mt-gene order is highly variable within molluscs, and changes
in gene order often involve changes in strands the genes are encoded on. A change from the light to
the heavy strand, or vice versa, also changes the nucleotide substitution skews of A and T, and C and
G. This inhomogeneity leads to wrong model parameters in phylogenetic analyses and, therefore, to
unreliable or erroneous trees. We present ten unpublished mt-genomes in a phylogenetic analysis
with published data. A gene-by-gene comparison of strand skews reveals some pitfalls in the bivalve
data set and possible sources of errors. In addition, we report near-plesiomorphic gene orders from an
aplacophoran and a protobranch bivalve. This implies that extensive gene rearrangements have
occurred independently in all major conchiferan lineages. Consequently, gene order data may be
informative for lower level phylogenies but are unlikely to resolve the relationships among the classlevel
taxa.
Kidney anatomy of neogastropods: New insights into relationships, affinities and evolutionary
dynamics
Strong, Ellen E.
Smithsonian Institution, National Museum of Natural History, Department of Invertebrate Zoology,
P.O. Box 37012, MRC 163, Washington DC, 20013-7012,
Email: StrongE@si.edu
The landmark study of Rémy Perrier published in 1889 described the organization, histology and
circulation patterns of the kidney in a broad diversity of “prosobranch” gastropods. Perrier’s study
established the structural differences between the “kidney proper” and the nephridial gland, and
demonstrated that cypraeids, naticids and neogastropods possess kidneys with two lobes of excretory
lamellae with distinct structure and function. Since that time, few detailed comparative studies have
examined organization and circulation patterns of neogastropod kidneys. The only character routinely
described and/or cited in the context of neogastropod phylogeny is the degree of interdigitation of the
lobes. Thus, the extent to which this organ system can provide characters pertinent for assessing
relationships and affinities of neogastropods is unknown.
A comparative survey of neogastropod kidney anatomy, histology and blood supply has revealed
several new characters of renal organization and circulation and refined the distribution of characters
already documented among neogastropods and potential outgroup taxa. In addition to degree of
interdigitation, characters found to vary relate to extension of the kidney roof into the mantle cavity,
distribution of primary and secondary tubules, development of secondary tubules, blood supply
patterns of the dorsal branch of the afferent renal vessel, and penetration of the afferent renal vessel
by the gland of Leiblein terminal ampulla. These characters vary at a number of taxonomic levels
suggesting a potential utility in lower and higher order systematics. The distribution of these
characters will be reviewed in a broad comparative context, including an assessment of putative
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