From Poe to Ponder…and Lindberg: Introduction to the Symposium “Molluscs as Models in Evolutionary Biology”*

Known to students of our profession and concisely summarized most recently in Ponder and Lindberg (2008), Mollusca are, with an estimated 200,000 living species, one of the largest animal phyla, second only to the arthropods. The remarkably rich fossil record of molluscs throws light back into the earliest Cambrian revolution 543 million years ago, and ever since then we fi nd them in nearly every ecosystem on Earth. The classes of living and fossil molluscs comprise an array of diverse animals with the most varied body plans, ranging from minute worm-like animals dwelling between sand grains on the beach to giant squids in the deep sea, and from microscopic snails in leaf-litter to giant clams in coral reefs. As objects of fascination, function, and food, molluscs play important roles in many cultures and societies. They include many taxa of immense economic signifi cance, such as oysters, scallops, and squids; some bivalves produce precious pearls, and some snails carry diseases that infect millions of people, especially in the tropics. Yet we feel that it is not only a curious fact in the history of science, but, unfortunately enough, much more a symptomatic indication of our discipline that it was not a professional naturalist or scientist with an interest in malacology, but the poet Edgar Allen Poe (1809-1849), who formulated an idea with much future. Poe was among the fi rst to recognize and explicitly recommend that the study of molluscs requires a combined analysis, which in his times meant reconciling a classifi cation based on hard shells with evidence from soft body anatomy (see details on this in the opening remarks to the symposium by Glaubrecht (2009)). This synthetic idea was long ignored by conchologists, who continued to classify molluscs almost exclusively based on features of their shell, while neglecting the soft body and the biological information that it holds. As a consequence, for a long time we knew few hard facts, for example, about the evolution and phylogeny of these soft-bodied animals but instead had much speculation by self-proclaimed authorities in the fi eld. In addition, most contributions in malacology long centered around morphology, anatomy, and in particular phylogenetic relationships within and among constituent taxa. Only rarely have molluscs been utilized explicitly as models for the study of the general aspects of evolutionary biology. However, molluscs, with their many features and facets, are highly suitable for providing some fundamental insights into the mechanisms of the genesis of biodiversity, its pattern in historical biogeography, and the underlying processes of speciation and radiation. An increasing number of recent studies and publications on molluscs reveal this rich potential. Therefore, it was the aim of this symposium on molluscs as models in evolutionary biology, held during the World Congress of Malacology (WCM) in Antwerp from the 15th to 20th July 2007 (jointly organized by Unitas Malacologia and the American Malacological Society), to bring together experts and their expertise to provide—based on molluscs— some of those fundamental studies, and to show avenues for using data that are of relevance for evolutionary biology. With 43 talks over more than two full days of sessions (plus several posters), this symposium was the largest at the Antwerp WCM. Following the introduction, two invited keynotes or plenary lectures were given, one by Suzanne Williams and David Reid (on global pattern of diversity and speciation) and one by Thomas Wilke and Christian Albrecht (on genesis of biodiversity, focusing on ancient lakes). Other lectures covered a wide array of topics ranging from biogeography, shell morphology and evolution, molecular phylogenetics, radiations and extinctions as documented in the fossil record, to mitogenomics, and aspects of development and reproduction. From all these presentations, a selection of eleven contributions were made, and we invited the authors to work out their main subject as exemplars for their specifi c area of research, viewed from their individual perspective. Subsequently, eight of the original speakers have been able to provide manuscripts for the American Malacological Bulletin.