Biology and Evolution of the Bivalvia - Cambridge, 14-17 September 1999

[The abstracts from the meeting have been added to the Society's web site. They can be found under the "Past and forthcoming meetings" link on the home page at: http://www.sunderland.ac.uk/MalacSoc/msl1.htm

Mid-September in Cambridge saw one of the largest and most successful meetings ever organised by the Malacological Society. This symposium organised by Liz Harper attracted bivalve researchers from some 21 countries. A most important part of the meeting was the mix of palaeontologists and biologists. An especially distinguished participant was Norman Newell, the doyen of American bivalve palaeontologists.

Bivalves have a long and rich fossil history and their shells are often amongst the most abundant of fossils. Moreover, the shells of bivalves through their shape, muscle attachment scars, hinges, ligaments, growth lines, microstructure and chemistry reveal more information about the life habits of the animal than for any other molluscan class. A continuous and detailed record of the whole life history of the bivalve from the larva to the adult is contained within the shell. Additionally, the life environment leaves chemical and structural signatures in the shell which can be used to interpret both the ontogenetic and palaeoenvironmental history. For these reasons palaeontologists have long been to the forefront of evolutionary and functional studies of bivalves.

The three day meeting was packed with papers and posters from a remarkable diversity of different topics. In order to accommodate all the participants, talks (68 in all) were strictly limited to 15 minutes only. It was soon apparent that this combined with a judicious mixing of topics in the programme was one of the great successes of the meeting. Additionally, 27 poster presentations were on display and these were viewed at special lunchtime sandwich and beer sessions. Video sequences of bivalve feeding were also shown during another lunchtime "feeding" session.

The papers presented at the meeting covered an extraordinarily varied range of topics which ranged from functional morphology of shells, bodies and organs, molecular and morphological phylogeny, physiology, ecology and palaeoecology, global biogeography, and taphonomy.

As might be expected, phylogenetic studies were prominent at the meeting and new molecular phylogenies were presented at the broad level for all bivalves (Campbell) and the Pteriomorphia (Steiner). The early radiation of the bivalves is being investigated through careful studies of newly discovered Lower Palaeozoic bivalves (Cope, Ratter). New morphological phylogenies were also presented for the Anomalodesmata (Harper et al.), for the rudists (Skelton) and Triassic cementing bivalves (Hautmann). Molecular phylogenies are providing a framework for testing adaptational hypotheses such as the evolution of reproductive strategies in oysters (O'Foighil & Taylor) or the evolution of cementation in Unionoidaea (Bogan & Hoeh). At a more detailed level, molecular studies are being used to unravel the complex relationships of living Mytilus species (Daguin et al.), brackish and freshwater cockles (Schneider & Magyar), Crassostrea species(Boudry & Huvet) and threatened freshwater mussels from the southern USA (Lydeard et al.). New morphological characters are being developed with great potential in phylogenetic analysis including the ultrastructure of bivalve sperm (Healy, Keys), gill structure (Benninger, Kornuishin), ligament growth patterns (Carter & Campbell, Thomas, Johnston & Collom), and larval shell form (Malchus, Yancey & Heany).

Biogeographic patterns and processes were addressed by both zoologists and palaeontologists. The structure and origin of latitudinal gradients in diversity continue to fascinate (Jablonski et al.; Crame). But the data upon which these analyses depend need painstaking work to assemble, as for the Florida Keys (Bieler & Mikkelson) and for the analysis of longer term faunal change in the Caribbean (Todd & Jackson). Molecular techniques are now being employed to unravel biogeographic histories as demonstrated in pearl oysters Pinctada (Arnaud et al.) and deep sea protobranchs (Zardus et al.).

Functional studies of bivalves included the experimental analysis of swimming in scallops (La Barbera), in situ endoscope studies of gill structure (Dimock) and particle processing (Levinton, Benninger), flume experiments on the hydrodynamics of hippuitid rudists (La Barbera) and an analysis of metabolic rates in Antarctic animals (Peck). Functional morphology studies included a review of the structure and function of bivalve eyes (Morton), anatomical adaptations to chemosymbiosis by Lucinidae (Taylor & Glover), tube formation in clavagellids (Savazzi), rib formation in oysters (Checa & Jimenez) and, from the Mesozoic, reconstructions of the mode of life of the weird Opisoma (Aberhan), the Retroceramidae (Damborenea & Johnston) and large inoceramids (Seilacher et al.).

Ecological and palaeoecological studies included a review of marine mussel ecology and adaptations (Seed & Richardson); the colonization by bivalves of hydrothermal vents (Lutz et al.); the ecology of freshwater mussels (Aldridge); burrowing behaviour (Edelaar & Welink) and reproductive output (Beukema & Honkoop) of Macoma; the effect of reproduction on the performance of Chlamys (Brokordt et al.); the population density of the coral-associated Pedum (Kleemann); naticid predation on Miocene corbulids (Arpad); the distribution of Mesozoic and Cenozoic bivalves from Japan (Kondo et al.) and the association of giant bivalves with Cretaceous cold seep sites (Kelly et al.). The relation of bivalve death assemblages to the living community was considered by Kidwell and the causes of shell scars on Glycymeris shells investigated by Ramsay et al.

The ontogenetic record embedded in the shell was used to measure growth rates as a test of ideas about how heterochrony influenced adult morphology in Jurassic Gryphaea (Jones) and the shape changes with age were analysed in Cenozoic Spissatella (Crampton). The use of ontogenetic changes in shell chemistry as a record of environmental changes was demonstrated using scallops (Johnson) and mytilids (Richardson & Seed).

Wine receptions were held amongst the exhibits of fossils in the Sedgwick Museum, and the more recently dead in the Zoological Museum and the conference banquet in the historic dining hall of Gonville and Caius College.

The general impression from participants at the end of the three days was that the meeting had been highly successful. It brought together an interesting mix of researchers from widely different disciplines. The format of 15 minute talks loosely arranged by approach rather than subject, avoided "ghettos", for example, of palaeontologists or "unionid papers".

Everyone comes away from meetings with different impressions but here are a couple of my own. It is clear that the molecular analyses being produced by different research groups will soon provide a robust phylogenetic framework for the classification of the bivalves and for the testing of ideas concerning the evolution of particular organs or morphological features. At a more detailed level, molecular phylogenies will be increasingly available for particular families and clades allowing investigation of evolutionary and biogeographic histories, speciation rates etc. Integration of morphological phylogenies and Lower Palaeozoic fossils, in particular, with these new molecular phylogenies will be a difficult and exciting challenge.

Despite the new techniques, exciting discoveries are still being made by simple field work and careful observations. It is less than twenty years since the discovery of either carnivory or sulphide-oxidising chemosymbiosis in bivalves, and new living animals with unusual lifestyles are still being found. Palaeontologists, also, continue to unearth wonderful and extraordinary animals which truly extend our concepts of morphological disparity amongst the bivalves. It is salutary to be reminded that animals living today are only a limited subset of the possible evolutionary range of bivalves.

Liz Harper and her team at Cambridge are to be congratulated on a stimulating and well organised meeting.

John Taylor

Both Elizabeth Platts and Kathe Jensen took some photographs of the events at Cambridge. These are presented on one page in the paper based bulletin but can be viewed here individually.

Some of these are named but not all. If you would like to be individually identified on these photographs please Email me at: A.Cook @ulst.ac.uk - indicating which photograph you are on and I will revise the credits.

1. John Taylor presents a book to Liz Harpur Photograph 1

2. Normal Newell, his wife Jennifer and Thomas Waller Photograph 2

3. Serge Gofas accompnied by the conference organiosers Sandra Last and Gillian Foreman Photograph 3

4. Kathie Way and Emily Glover Photograph 4

5. John Healy and Gerhard Steiner Photograph 5

6. Can you see yourself at the reception in the Museum Photograph 6, Photograph 10 and Photograph 12

7. Or at coffee? Photograph 8 and photograph 9