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Manuel Caballer Gutierrez, Area de Ecologia, ETS Caminos, Canales y Puertos, Universidad de Cantabria, Avda de los Castros s/n, Santander, Cantabria, Spain
E-mail: manu...@hotmail.com
The Bay of Santander is in the Gulf of Biscay, to the North of Spain. Its fauna has always been influenced by the Gulf Stream, that causes the temperature of the water to be no lower than 14şC in winter, and 18şC in summer. In 2001 I began the elaboration of my doctoral work "Opisthobranch Molluscs of Santander Bay: selection of species for chemical prospecting". As a result of field work it is evident that certain species which were previously regarded as belonging to the faunas of the Mediterranean Sea, Macaronesia or the south of Spain, have the northern limit of their distribution in the Bay of Santander, from where they were not recorded before. These species include Placida verticillata, Placida brevicornis, Runcina adriatica, Cuthona ocellata, Flabellina affinis and Doto fructifraga. Other remarkable species that also are present in the Bay are: Thordisa diuda, a South Atlantic species, Polycera hedgpethi, a species described in the Pacific that is recorded for the second time in Europe and Doto floridicola, already captured in England but not in so great nor stable populations as in this zone.
Figures
Flabellina affinis, Cuthona ocellata, Doto floridicola
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Effects of a treated sewage effluent on Lymnaea stagnalis, Planorbarius corneus and Viviparous viviparous, three European freshwater molluscs with different reproductive strategies
Clarke, N.A., Casey, D., Garner, A., Hala, D., Dagnac, T., Walker, D., Janbakhsh, A, Hutchinson, T, Tattersfield, L, Pascoe,D and Jobling, S., Brunel University, Uxbridge, Middlesex, UB8 3PH
E-mail: Neil...@brunel.ac.uk
Treated sewage effluents represent a highly complex mixture of chemicals, including endocrine-disrupting chemicals (EDCs), that can interact with the physiological systems of animals and cause alterations in reproductive and developmental processes. Most studies to date have focused on characterising the effects of treated sewage effluents on fish and it is well established that endocrine disrupters, present in treated sewage effluents, are responsible for the widespread occurrence of hermaphrodite roach (a coarse fish species) in rivers throughout the U.K. Although the disruptive effects of EDCs have been found in a range of wildlife populations, little attention has been focused on ecologically important invertebrate groups, such as freshwater molluscs. Some of the most vulnerable and threatened molluscs, both in the U.K. and in Europe, are marsh or freshwater species and many of these taxa have shown dramatic declines, particularly in the last 30-40 years. Eutrophication has been cited as one of the reasons for the declines of freshwater molluscs throughout Europe, although specific links between species declines and sensitivity to pollution remain unknown. In this study, the effects of exposure to a graded concentration (0, 25%, 50%,100%) of a treated sewage effluent on reproductive and developmental processes in the pulmonate snail species, Planorbarius corneus and Lymnaea stagnalis and in the ovoviviparous prosobranch, Viviparous viviparous, were studied. The hormonal activity (measured using the yeast androgen and oestrogen screens) and concentrations of sex steroid hormones, alkylphenols, bisphenol-A and organotins in the effluent were also measured.
The results confirmed that the effluent was both oestrogenic and anti-androgenic and that sex steroids (E2, E1) and alkylphenols, Bisphenol-A and organotins were present. Lymnaea stagnalis experienced high rates of mortality across all treatments (including the controls) compared with the other two snail species. Moreover, the production of eggs or embryos by all species of snail, was shown to be dependent on the concentration of effluent (and hence of EDCs) to which they were exposed: In Planorbarius corneus, there was an increase in the number of spawning masses laid by each snail with increased exposure to effluents and hence, the greatest number of spawning masses were produced by snails exposed to 100% effluent relative to the control treatments. Conversely, however, in the same species of snail, there was a dose-dependent decline in both the weight of each egg mass and in the number of eggs contained within the egg mass. Similar effects were also observed in Viviparous viviparous, which experienced a decline in the number of embryos contained within the brood pouch with increased exposure to the effluent. In Lymnaea stagnalis, there was a decrease in the number of spawning masses produced by snails exposed to 100% effluent relative to the control treatments. As no change in the number of eggs within an egg mass was observed, the total numbers of eggs produced by each snail during the exposure period decreased with increasing effluent concentration.
These data indicate that all three species of mollusc are sensitive to the effects of treated sewage effluents but that inter-species differences in the nature of the response exist.
Further work is needed to characterise the longer term effects of this effluent on these molluscs and to determine the nature of the causative agent(s).
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Jennifer Gallichan & Harriet Wood, Biodiversity & Systematic Biology, National Museum & Galleries of Wales, Cathays Park, Cardiff CF10 3NP
E-mail: Jenn...@nmgw.ac.uk
César-Marie-Felix Ancey (1860-1906) was a keen land snail collector with a wide geographical interest. His focus was mainly on those from the Pacific and Asia but also covered Europe and Africa. In his short career he described some 550 taxa and published over 140 papers. After Ancey's death, Fischer (1908) published a list of his many small publications on Mollusca and Geret (1909) published a list of Ancey's new species names. Neither of these lists are however complete. Our current project is to research and image the Ancey material in our collections and compile a fully updated list of Ancey's new names. The results of this will then be compiled into a museum publication.
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Jürgen Geist, Wildlife Biology and Management Unit, Technische Universität München-Weihenstephan, Am Hochanger 13, D- 85354 Freising, Germany
E-mail: Juer...@wzw.tum.de
Freshwater pearl mussel (Margaritifera margaritifera) populations in Central Europe are critically endangered with only a few populations still successfully reproducing. Conservation and management programmes require information on the genetic structure of remaining populations as a tool for conservation strategies and management programmes, including the identification of priority populations of conservation and for specific management recommendations. We developed 14 microsatellite markers for M. margaritifera and investigated the genetic structure of 24 pearl mussel populations from five Central European drainage systems of Elbe, Danube, Maas, Rhine and Weser. We suggest a non-destructive sampling method of haemolymph for DNA analyses which did not cause any mortality among sampled mussels in this study and which can therefore also be suggested for DNA sampling of other bivalve species. Microsatellite analyses revealed an overall high degree of fragmented population substructure and marked differences in the in the genetic diversity of populations. The observed genetic structures can be explained by historical and demographic effects and have been enforced by anthropogenic activities. Distinct conservation units (CUs), as revealed from high FST-values, private alleles and genetic distance measures, should be managed separately and were detected even within drainage systems. Assignment tests revealed high levels of correct assignment to present-day drainage systems and lower levels of correct assignment in the contact zones of different drainages. Within connected river systems, lowest genetic diversity was usually observed in headwater regions. Census population size and genetic diversity measures showed weak correlations, indicating that detailed genetic analyses are mandatory for selection of priority populations for conservation. Figures
Conservation priorities for freshwater pearl mussel.
Adapted from Geist J, Kuehn R (2005) Molecular Ecology, 14, 425-439.
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Michal Horsák, Department of Zoology and Ecology, Faculty of Science, Masaryk University, Kotlářská 2, CZ-61137 Brno, Czech Republic
E-mail: hor...@sci.muni.cz
Genus Pisidium (pill-clams) belongs to the family Sphaeriidae, which comprises the smallest bivalves of all. Pill-clams are simultaneous hermaphrodites, viviparous and mostly mud dwelling animals, which are able to burrow in the sediment. They have a cosmopolitan and ubiquitous distribution but they are exclusively found in limnic habitats and represent an ecologically important group that has the potential for utilisation in biomonitoring. Up to date, fourteen pill-clam species are known from the Czech Republic. Four of them are restricted to running water habitats, three species inhabit only standing waters, and the remaining seven species occur in both running and standing waters. Caused by different individual species requirements, pill clam communities of running waters (altogether eleven species) closely match with longitudinal zones according to Illies & Botosaneanu as indicated in the figure below.
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Sally Howlett and Gordon Port, Invertebrate Zoology Research, School of Biology, Ridley Building, University of Newcastle upon Tyne, Newcastle upon Tyne NE1 7RU.
E-mail: Sall...@newcastle.ac.uk
The field slug, Deroceras reticulatum, is a major pest of arable crops in the UK, especially oilseed rape and winter wheat. A series of experiments were carried out to investigate the effect of laying season and rearing temperature on the growth and survival of this species. Slugs hatching from eggs laid in spring or autumn 2002 were reared at one of three temperatures (12°C, 15°C or ambient temperature). Growth and survival were monitored over a period of 20 weeks. Hatching season significantly affected growth at all three temperatures. At ambient conditions growth was slower in autumn hatching slugs compared to those hatching in spring, whereas at each of the constant temperatures the opposite was observed. Survival was also influenced by hatching season for slugs reared at ambient temperature and 15°C; it was higher in autumn for the former and spring for the latter. There were no differences in survival between hatching seasons for slugs reared at 12°C.
Slugs from the same batch may differ ten-fold in size.
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Lucie Juřičková, Department of Zoology, Faculty of Science, Charles University, Viničná 7, CZ-128 44 Praha 2, Czech Republic
E-mail: luci...@seznam.cz
Cities represent a rich spectrum of habitats in human impact of variable intensity and of variable time. Molluscan fauna of three cities in the Czech Republic was investigated (Prague, Pilsen, Hradec Králové). Molluscan communities of substitute habitats and of the fragments of natural habitats in marginal zones of the cities were characterized. The occurrence of 158 species in 270 localities was recorded. Most species were recorded in Prague, which reflects the high geological and vegetational diversity of the urban area. The species diversity of various habitats in cities is very different, but the total species diversity of cities is high. Widespread species and species of ecological groups 1 (forest species) and 7 (species with a wide ecological range) occurred more frequently in urban environments. Some species index of three various human impacted zones were selected. All species were also classified in relation to their tolerance of human impact. Cities represent the substitute biocentres of characteristic molluscan communities.
Figure.
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The Systematics and Evolution of Bullidae (Gastropoda: Opisthobranchia)
Manuel António E. Malaquias and David G. Reid, Department of Zoology, The Natural History Museum, London SW7 5BD
E-mail: man...@nhm.ac.uk
The study of evolution and speciation of tropical marine invertebrates is still at an early stage, with many questions unanswered. Several hypotheses of speciation have emerged, differing in their emphasis of vicariant or dispersal events, speciation in sympatry or allopatry, and geological time scale.
Bubble shells (Bullidae) are a small, worldwide family of gastropods with predominantly tropical distribution, but with a few species also present in temperate waters. These attributes make this group an excellent case study to evaluate patterns of biogeography and evolution on a global scale. Nevertheless, the use of Bullidae as a model requires first a comprehensive systematic revision of the group, since the taxonomy is extremely confused with over 100 available species names of Bulla.
This project is the first attempt
to incorporate data on shells, anatomy and molecular sequences of
all available living species of Bullidae in a phylogenetic and biogeographic
analysis. The main objectives are to produce a species-level phylogeny
as a basis for hypotheses of evolutionary radiation, adaptation
and biogeography, and to review and clarify the taxonomy.
The preliminary molecular trees are consistent with the monophyly of Bullidae, and with the presence of an Indo-West Pacific clade. Morphological characters are both variable within species and similar among them, and none proved to be alone good enough for species diagnosis. Shells and reproductive structures are the most informative, but different sources of information must be combined in order to delimit species. Overall 19 species of Bulla are recognized: 4 in the Atlantic and Mediterranean, 13 in the Indo-West Pacific, and 2 in East Pacific. A peak of diversity occurs in the Indo-Malayan area where the distributions of 6 species overlap. This pattern suggests isolation between the Atlantic and the Indo-Pacific after the closure of the Tethys Sea during the early Miocene, followed by species radiation.
Distribution of four Bulla species in Atlantic and Mediterranean
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The effect of shell colour on activity of the land snail Cepaea nemoralis in outdoor cage experiments
Malgorzata Ozgo, Institute of Biology; Pomeranian Pedagogical University; Arciszewskiego 22B; 76-200 Slupsk; Poland
E-mail: moz...@wmc.com.pl
Differences in behavioural responses to solar radiation were examined in yellow and brown unbanded Cepaea nemoralis. The experiments were carried out during summer months in various weather conditions. Prior to each experiment, the snails were immersed in water until all individuals became active. They were then placed in cages and observed for an hour up to two hours at 5 minute intervals. Air temperature and humidity readings were taken at the same intervals.
>In the range of temperatures examined in this study, air humidity was the most likely factor causing differences in the activity of the morphs. At air humidity of approximately 90%, all snails remained active throughout the experiment, irrespective of the colour of the shell. At air humidity of over 70% brown snails remained active significantly longer than yellow ones. At air humidity of over 70% brown snails remained active significantly longer than yellow ones. At humidities below 70%, yellow remained active significantly longer than brown ones, and the time until inactive was shorter with decreasing air humidity. Differences in the time snails remained active in these experiments indicate that yellow and brown C. nemoralis might be adapted to different climatic conditions.
On hot and dry days brown shelled snails became inactive more quickly than yellow ones; when the sky was overcast brown-shelled snails tended to remain active as long as or longer than the yellow ones. As becoming inactive is one of behavioural adaptations for avoiding thermal stress and dehydration in the land snails, observed differences in activity are probably related to the thermal properties of the shells.
Two colour forms of C. nemoralis
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Spatial variability of molluscan successions from the early Holocene of Ireland and its relevance to biogeography, human impact and climatic history
George Speller, University Museum of Zoology, Downing Street, Cambridge CB2 3EJ, UK.
E-mail: grs...@cam.ac.uk
The tufa deposit at Newlands Cross, Co. Dublin is the only site to have yielded a detailed early Holocene land snail succession from Ireland. This sequence has not only provided much needed empirical data relating to the historical biogeography of the Irish fauna but has also shown clear evidence of forest disturbance in the upper levels. New work at this site has sought to investigate the spatial extent and scale of human impact by analysing multiple tufa profiles within a small area. Since the molluscan succession is so dynamic, it is possible to correlate profiles with some confidence. However, differences between the successions are evident and, in particular, the anthropogenic signal seen in the original record is not so apparent in others. As an aid to environmental interpretation, some stable isotope analyses have been undertaken on bulk tufa samples. Preliminary data show that these correspond remarkably well with major changes in the molluscan fauna.
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Progress and plans of a Molluscan PhD:
Cilia ontogeny, nature and functioning on the mantle rim, velum and gill bud of C.gigas, O.edulis and Lyrodus pedicellatus larvae
Sam Stanton, Institute of Marine Sciences, School of Biological Sciences, University of Portsmouth, Ferry Road, Portsmouth, PO4 9LY, UK
E.mail: sam....@port.ac.uk
The nature and ontogeny of the ciliation on the mantle, velar rim and developing gill for C.gigas and O.edulis has been examined by SEM and LM. Ordered and complex cilia groupings have been revealed by fracturing the shells of dehydrated veliger and pediveliger larvae. In both veliger and pediveliger, a grouping of mantle cilia with a microvillus corona around the base has been revealed near the hinge. A similar group also appears near the base of the developing gill. The ciliation of the inner mantle rim increases in complexity from the veliger to the pediveliger stage. The cilia form rows along the anterior margin of the mantle, beginning from the gill bud and forming a distinct twin tract of cilia running around the mantle margin by the pediveliger stage. Information from SEM will be summarised into cilia distribution maps for each development stage. These maps will be directly compared to other bivalve larvae, including other ostreids, pectinids and teredinid bivalves. SEM has revealed a previously undescribed row of compound cilia on the velum of O. edulis beneath the two rows of pre-oral compound cilia typical of bivalve veligers.
New work has included preliminary observations of the velum of brooded larvae of Lyrodus pedicellatus, revealing a much denser adoral row, particularly in larvae that probably had not developed to the point where they were ready for release from the adult. Future plans for the work include TEM examination of the mantle region with special attention to the area around the groupings featuring microvillous coronae and the use of fluorescence CLSM to map the emerging neural network. In addition, swimming behaviour will be used to assist with interpreting the functional significance of the anatomical observations.
Fig.
Velum of Lyrodus pedicellatus, showing dense ad-oral row,
distinct inner pre-oral row with microvilli transition,
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Sid Staubach and Annette Klussmann-Kolb, AG Phylogenie und Systematik, Department of Ecology and Evolution, Zoologisches Institut, Johann Wolfgang Goethe Universität, Frankfurt
E-mail: Stau...@zoology.uni-frankfurt.de
The Cephalic sensory organs (CSOs) of the Opisthobranchia show a great diversity in the different ophistobranch orders. They can be identified as cephalic shields, oral veils, Hancock´s organs, lip organs, rhinophores or labial tentacles, and are generally believed to have chemo- and mechanosensory functions. The overall morpholgy of these organs is well known, but details of the sensory epithelia and innervation patterns of these structures are less studied.
Our aim is a comparative study of the CSOs for the major opisthobranch orders. We will present preliminary results about the cellular innervation of different types of CSOs in "Cephalaspidea s.l." and Anaspidea. Moreover we use immunoreactivity to several neurotransmitters (Fmrf, 5HT, TH) to characterise the different sensory epithelia.
Based on these results we will discuss hypothesis regarding homologies and functions of different CSOs in different taxa. This will help us to eventually understand the evolution of these organs in opisthobranchs and by comparison with other gastropod taxa in gastropods in general.
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