World Congress of Malacology Antwerp ... - Unitas Malacologica

species in a parsimony analysis of endemicity to delineate candidate AoE, and use multivariate
analysis to define groups of biotic elements on the basis of species interactions (co-occurrence,
exclusion, neutral). To examine the utility of our method we analyze the well-known data set of
Sciobius in southern Africa, as well as data on invertebrate taxa endemic to the island of Crete
(Greece). Our results are very similar to those of previous analyses, and produce meaningful
delineation of areas of endemism and biotic elements in both data sets. Furthermore, our method is
flexible regarding null models and significance levels, and eliminates data noise.
Molecular versus morphological taxonomy:
a case study of character evaluation in marine Gastropoda
1, 2
Gittenberger, Adriaan
1. Muséum National d'Histoire Naturelle, 55, rue Buffon, F-75005 Paris, France,
Email: GittenbergerA@Naturalis.nnm.nl
2. National Museum of Natural History Naturalis, P.O.Box 9517, 2300 RA Leiden, The Netherlands
Molecular analyses are still becoming increasingly important in taxonomical, ecological,
biogeographical and evolutionary studies. However, regardless of the various applications of
genomics and the rapid progress in for example computer methodologies, one will always need oldfashioned
alpha taxonomy to get a better view of the world around us. Especially cases in which
morphological and molecular analyses do not give congruent results, prove to be valuable in studying
evolutionary principles, behavioral ecology and/or ecosystem complexity. In these studies the
seemingly misguiding data in either the molecular or the morphological dataset is often used to
illustrate interspecific relationships, co-evolution, parallel or convergent evolution, bottleneck events,
etc. In marine gastropods large-scale research projects combining genetic and alpha-taxonomical
studies have recently been performed in the families Cypraeidae, Epitoniidae and Coralliophylidae.
By analyzing both molecular and morphological data, convincing evidence was found for the
frequent occurrence of convergent evolution in conchological characters, and cryptic, adaptive
radiation of snail species that cannot unequivocally be distinguished on the basis of shell or
anatomical characters alone. Furthermore, these studies played an important role in molecular and
morphological character evaluation for taxonomical studies of Mollusca more in general. For
example, some genetic markers proved to be less valuable than others because of saturation in some
but not all lineages of a clade. Such findings could be correlated with alpha-taxonomy or ecological
characters of the taxa concerned. Molecular and ecological support was found for the hypothesis that
characters of the teleoconch are less valuable for phylogeny reconstructions than those of the radulae,
jaws, opercula and egg-capsules in epitoniid snails.
Witnessing a 'wave of advance'
Gittenberger, Edmund
National Museum of Natural History, P.O. Box 9517, NL 2300RALeiden, The Netherlands,
Email: gittenberger@naturalis.nnm.nl
Shells of the terrestrial molluscan family Clausiliidae are characterized by the presence of a
clausilium with a door-like blade by which the aperture can be closed when the snail is inside.
Usually there is a relatively narrow bypass-canal next to the blade but in several (groups of) species
the clausilium may close the aperture completely. Apparently, the latter character state is the derived
condition, which evolved several times in parallel. In one case, among species of Alopiinae, there are
reasons to suppose that the genetic factor causing obsolescence of the bypass-canal has been
transmitted across incomplete species boundaries. When the character state 'obsolete bypass-canal' is
used for phylogeny reconstruction in that case, the results are in conflict with the outcome of both a
molecular analysis and biogeographical patterns, whereas extreme convergent evolution in other
conchological characters has to be accepted.
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