Calliostoma Zizyphinum Research Articles

Identification of Shell Colour Pigments in Marine Snails Clanculus pharaonius and C. margaritarius (Trochoidea; Gastropoda).

Colour and pattern are key traits with important roles in camouflage, warning and attraction. Ideally, in order to begin to understand the evolution and ecology of colour in nature, it is important to identify and, where possible, fully characterise pigments using biochemical methods. The phylum Mollusca includes some of the most beautiful exemplars of biological pigmentation, with the vivid colours of sea shells particularly prized by collectors and scientists alike. Biochemical studies of molluscan shell colour were fairly common in the last century, but few of these studies have been confirmed using modern methods and very few shell pigments have been fully characterised. Here, we use modern chemical and multi-modal spectroscopic techniques to identify two porphyrin pigments and eumelanin in the shell of marine snails Clanculus pharaonius and C margaritarius. The same porphyrins were also identified in coloured foot tissue of both species. We use high performance liquid chromatography (HPLC) to show definitively that these porphyrins are uroporphyrin I and uroporphyrin III. Evidence from confocal microscopy analyses shows that the distribution of porphyrin pigments corresponds to the striking pink-red of C. pharaonius shells, as well as pink-red dots and lines on the early whorls of C. margaritarius and yellow-brown colour of later whorls. Additional HPLC results suggest that eumelanin is likely responsible for black spots. We refer to the two differently coloured porphyrin pigments as trochopuniceus (pink-red) and trochoxouthos (yellow-brown) in order to distinguish between them. Trochopuniceus and trochoxouthos were not found in the shell of a third species of the same superfamily, Calliostoma zizyphinum, despite its superficially similar colouration, suggesting that this species has different shell pigments. These findings have important implications for the study of colour and pattern in molluscs specifically, but in other taxa more generally, since this study shows that homology of visible colour cannot be assumed without identification of pigments.

Response of benthic macrofauna to an oil pollution: Lessons from the “Prestige” oil spill on the rocky shore of Guéthary (south of the Bay of Biscay, France)

The benthic community on the rocky foreshore of Guéthary (France) has been monitored since 2002. The standardized and quantitative monitoring method counts 20 geographically referenced quadrats spread on three littoral zones: upper mediolittoral, lower mediolittoral and infralittoral zones. The setting up of this monitoring occurred when the “Prestige” sunk close to the Finistere Cape in Galicia (Spain). The oil slick following the shipwreck impacted the Guéthary foreshore in early 2003.After the “Prestige” oil spill, the taxonomic richness decreased in the studied area with a loss of 16 species – from 57 in 2002 (before the shipwreck) to 41 species in 2004. Two or 3 years later, taxonomic richness increased to a level observed prior to the oil spill.Along the years, temporal variations in community structure of benthic macrofauna are revealed by detailed analysis. Some polluo-sensitive species disappeared after 2002 and have not reappeared yet (e.g.: Hymeniacidon perlevis). Some others reappeared two or three years after the spill or even later (e.g.: Amphipholis squamata, Botryllus schlosseri, Calliostoma zizyphinum, Echinus esculentus, etc.). Noteworthy changes were found in 2004 driven by the sudden increase in abundance of grazers. The following years, these abundances went back to a stable level. The benthic community seemed to recover almost 5 years later, although a new composition of macrofauna populations was observed.In overall aspect, the complexity of the benthic ecosystem response to oil spills confirms the need of regularly updated baselines to assess the impact of pollutions and more generally to maintain marine biodiversity.

Variation in shell morphology of Calliostoma zizyphinum (Gastropoda: Trochidae)

Differences in shell morphology in the intertidal prosobranch mollusc Calliostoma zizyphinum were studied from a number of sites within four geographical regions of the British Isles with varying exposures to wave action and crab predation. Mean values of damage scarring were highest in shells sampled from Strangford Lough, Northern Ireland, and lowest in individuals from the Atlantic Coast. Shells collected from the Isle of Man were smaller than those from either the Atlantic coast of Ireland or Strangford Lough. Shells from Strangford Lough had taller shells (higher aspect ratio) than shells from the County Down and Atlantic Coast and shells from the County Down coast were more squat (lower aspect ratio) than those from all other areas. Shells from Strangford Lough were significantly thinner than shells from all other geographical areas. The relationships between shell damage scarring and shell size and tallness were not consistent among areas. Shells from Strangford Lough are notable in showing a steep, positive relationship between shell size and scarring and a steep, negative relationship between scarring and tallness. The unusual shell phenotypes observed in shells from Strangford Lough may be explained by rapid shell growth, which would not only allow Calliostoma to attain a size refuge from crab predators but also to recover successfully from repeated crab attacks on the shell lip. Such a strategy would result in larger, thinner shells with a high number of damage scars.

Food web studies in a Norwegian kelp forest based on stable isotope (δ13C and δ15N) analysis

Samples of kelp Laminaria hyperborea, various species of red algae, phytoplankton, material from sediment traps, invertebrates, fish and seabirds were collected on the west coast of Norway and the abundance of stable isotopes was analyzed. Canopy plants of L. hyperborea were most 13 C depleted in spring and there was a significant difference between the basal (δ 13 C: -16.65‰) and distal (δ 13 C: -18.67‰) parts of the lamina. Young kelp plants were more 13 C depleted (-23.59‰). The red algae fell into 2 groups: one in the same range as kelp plants (δ 13 C: -18.93 to -22.27‰) and the other highly depleted (δ 13 C: -32.85 to -34.38‰). Phytoplankton showed an average δ 13 C value of -24.44 ‰. δ 15 N values from L. hyperborea differed between the basal (δ 15 N: 5.54 ‰) and distal (δ 15 N: 3.54 ‰) part of lamina. δ 15 N values for all primary producers values were in the range of 3.52 to 5.78 ‰. Among the gastropods, Helcion pellucida proved to be a kelp plant grazer, Lacuna vincta probably fed on both kelp and various species of red algae, whereas Aplysia punctata grazed exclusively on the most 13 C-depleted red algae. δ 15 N values for 2 other gastropods, Gibbula sp. and Calliostoma zizyphinum (8.64 and 10.30%o, respectively), suggest that they belong to higher trophic levels. Filter feeders occupied lower trophic levels and received variable carbon inputs from kelp. The only group of animals with δ 13 C signals in the same range as phytoplankton were amphipods. Based on δ 15 N values, the fish varied from intermediate to top consumers (trophic level: 2.6 to 3.3). Two species of seabirds were included in the study and their δ 15 N values suggested 2 different trophic levels, which correspond to their known feeding preferences. A mixing model suggests that kelp-derived carbon plays an important role in this nearshore system and that kelp may serve as a carbon source for marine animals with several different types of feeding strategies.

Shell wiping in Calliostoma zizyphinum: the use of pedal mucus as a provendering agent and its contribution to daily energetic requirements

The phenomenon of shell wiping in Calliostoma zizyphinum (L.) was investigated with regard to its potential function as a feeding adaptation. It was determined that C. zizyphinum will, on average, wipe the surface of its shell with its foot twice every 24 h, in the process consuming any mat- ter that has adhered to the pedal mucus present on the surface of its shell. Examination of the impor- tance of shell wiping to C. zizyphinum, both as a mechanism to reduce shell fouling and as a source of nutrition, revealed that the prevention of shell wiping resulted in a reduction in shell growth by a factor of 0.67 and an increase in shell fouling by a factor of 9. Measurement of the metabolic rate of C. zizyphinum ascertained that an average sized adult had a metabolic requirement of ~117 J 24 h -1 . Examination of the ability of the pedal mucus produced by C. zizyphinum to act as a provendering agent showed that the pedal mucus produced by C. zizyphinum could increase the entrapment of particulate matter by a factor of 8, and increase the chlorophyll a content of a substratum by a factor of 3. Calculation of the potential contribution of the matter trapped by pedal mucus, which is ingested through shell wiping, to the daily energetic requirements of C. zizyphinum revealed that shell wip- ing can contribute to approximately one-fifth of the daily energetic requirement of C. zizyphinum. Shell wiping therefore has an important role for both feeding and antifouling in C. zizyphinum.

A method for spatial and temporal assessment of gastropod grazing intensity in the field: the use of radula scrapes on wax surfaces

The feeding apparatus of many marine molluscan herbivores leaves distinctive marks on the surface of dental wax. This method can be used in the field to assess the spatial and temporal patterns of gastropod grazing on rocky shores. Among the common gastropod grazers of intertidal habitats on the Isle of Man, distinctive rasping marks were made by docoglossan ( Patella vulgata.), rhipidoglossan ( Calliostoma zizyphinum. and Gibbula spp.) and larger taenioglossan ( Littorina obtusata.) grazers. Our technique for the field deployment of wax surfaces is simple, inexpensive, and permits a realistic placement of the wax surface in the environment. This placement is achieved by casting the wax into small discs (14 mm diameter) and setting them into pre-formed holes in the rock surface. By quantifying either the number of discs scraped or the area of the wax surface scraped, patterns of grazing intensity (defined as areal extent of the surface grazed in a given period) can be assessed over a variety of spatial and temporal scales. To illustrate this method and refine its use, we recorded the grazing patterns of the limpet Patella vulgata for periods from 12 h to 17 days. The optimal period of deployment depended on the specific habitat, but we often found periods of 1–14 days to be appropriate. Regular arrays of discs also demonstrated that grazing intensity was spatially variable at a scale of 0.25 m, and that grazing intensity increased throughout the late winter and spring. This method provides a cheap and direct measure of feeding intensity that is directly relevant to understanding the effect of grazing molluscs on algal communities. Moreover, it can be used over a variety of spatial and temporal scales.

A comparison of the strengths of gastropod shells with forces generated by potential crab predators

Carcinus manenas, Liocarcinus puber and Cancer pagurs are thought to be three likely crab predators of the gastropod Calliostoma Zizyphinum. In order to compare the strenghts of predators and their prey, the whole shell and aperture lip strengh of white and pink Calliostoma morphotypes and the maximum forces exerted by the chelipeds of three crab species were measured. Although white shells were thicker than pink shells, Calliostoma colour morphotyes did not differ significantly in either the force required to break the shell lip or the whole shell. Both Liocarcinus puber and Carcinus maenas have dimorphic chelipeds and their “crusher” chelipeds deliver almost double the forces generated by the‘cutter’chelipeds. In constrast, Cancer pagurus has monomorphic chelipeds both delivering similar forces.When compared with Calliostoma shell strenght, the forces generated by the‘crusher’chelipeds of most L. puber tested were, in general, sufficient to break the shell lip of Calliostoma shells, whereas forces generated by the‘cutter’chelipeds of only the larger individuals were sufficient to break the shell lip. In C. manenas, forces generated by both the‘cutter’and‘crusher’chelipeds often exceeded the minimum recorded force required to break the shell lip and the‘crusher’cheliped reached the minimum force required to break whole Calliostoma shells. Both chelipeds of all C. pagurus tested generated forces in excess of the minimum required to break the shell lip, and the proportion of individuals capable of generating the minimum force required to break the whole shell increased with the size of the size of the crab. Carcinus maenas and Cancer pagurus were capable of breaking both the shell lips and the whole shells of a wider range of shell sizes than L. puber.

MORPHOLOGICAL VARIATION IN THE PAINTED TOPSHELL, CALL1OSTOMA ZIZYPHINUM (L.) (PROSOBRANCHIA: TROCHIDAE), FROM INTER-TIDAL RAPIDS ON THE IRISH COAST

Shell shape variation in Calliostoma zizyphinum (L.) is examined with different techniques of analysis (profile, discriminant, canonical variate and ratio analysis). Shells are collected from five tidal rapids systems, all in very sheltered inlets, where C. zizyphinum is to be found at shore levels higher than the normal shore distribution of LWNT to the sublittoral. Shell morphology varies consistently with the local habitat conditions, such as water flow rate, relative exposure and shore level. populations can be distinguished using various shell parameters and shell profiles. Shells from two different levels in the same rapids show the effects of their subtly different habitats.

AN ANALYSIS OF SHELL SHAPE VARIATION IN THE PAINTED TOPSHELL CALLIOSTOMA ZIZYPHINUM (L.) (PROSOBRANCHIA: TROCHIDAE

Littoral and sublittoral Calliostoma zizyphinum (L.) from fourteen sites around Ireland are compared by a new method of shell shape analysis. The apparatus used is described and results show clear variation between populations. It is also used to show similarity between the variegated and white morphs found in Strangford Lough. Patterns of growth are shown to be largely in response to the habitat conditions encountered at each site. The mean apical angle of each population is shown to be of great importance in distinguishing populations of topshells, as it varies with the relative exposure of each site.

Tide-model analysis of the zonation of intertidal prosobranches. II. Four species of trochids (Gastropoda: Prosobranchia)

Experiments were carried out in a tide model to determine the patterns of zonation of four species of trochids under laboratory conditions. Calliostoma zizyphinum (L.), Gibbula cinera a (L.) and G. umbilicalis (da Costa) did not show a constant pattern of zonation. Monodonta lineata (da Costa) adopted the same zonation in the model as that previously described for Littorina litorea (L.), i.e. at and just below high tide level, but this was higher than normally found on the shore. Time-lapse monitoring of the movements of the four species showed that, except for Monodonta lineata, they were influenced by the rise and fall of the water level in the tank and tended to move up and down with it. Under conditions of reduced tidal period Calliostoma zizyphinum, Gibbula cineraria, and G. umbilicalis showed, however, a pattern of zonation more like that on the shore. Movement mainly occured during periods of submersion and the number of animals moving at any one time was very low. Monodonta lineata, and to a lesser extent, Gibbula umbilicalis could compensate for the increased rate of movement of water level during the 3-h tidal period by increased rates of movement and greater levels of activity. Thus, not only does the moving water level bring about the initiation of movement of the animals, but it also governs their rate of movement. None of the four species showed any differences in their patterns of movement or distribution whether in complete darkness, or continuous light. When under continuously damp conditions Monodonta lineata adopted a lower position in the model, possibly because of the movement of a layer of water over the substratum. Negative geotaxis was less strong in Calliostoma zizyphinum and Gibbula cineraria in the absence of a moving water level. The results indicate that, with the possible exception Calliostoma zizyphinum, the physical stresses due to emersion were unlikely to be the major control of zonation. It is considered possible that differential zonation shown on the sea shore by British littorinids and trochids might be governed by the different requirements of the species for food.

The Distribution of Intertidal Organisms Along the Coasts of the English Channel

The English Channel may conveniently be divided into a western basin and an eastern basin separated by a line drawn approximately between the Cherbourg peninsula and the Isle of Wight. In these basins, the environmental factors are very different. Thus the water of the western basin is on average warmer and slightly more saline than that of the eastern basin and its temperature variation is less extreme. The French side of the Channel is warmer than the English coast only in the western basin. The tidal oscillations in the two basins are out of phase with each other and the strongest tidal currents occur where the two basins join. The main residual flow is up-Channel with minor coastal eddies.The shores at the western end of the Channel are generally rocky, they are close to deep water, and so are exposed to frequent heavy swells. The shores of the eastern basin are generally erodible, and accumulations of sand and shingle tend to reduce the force of the waves. The water of the eastern basin generally contains more suspended matter and the shores are usually scoured by sand and shingle.The distribution of the following animals is given in some detail and compared with earlier records:Ammonia sulcata, Actinia equina, Chthamalus stellatus, Balanus balanoides, B. perforatus, B. crenatus, B. improvisus, Elminius modestus, Verruca stroemia, Hemioniscus balani, Patella vulgata, P. depressa, P. aspera, Monodonta lineata, Gibbula umbilicalis, G. pennanti, G. cineraria, Littorina saxatilis, L. littoralis, L. littorea, L. neritoides, Paracentrotus lividus. The distribution of certain other species is also discussed:Balanus balanus, Haliotis tuberculata, Gibbula magusandCalliostoma zizyphinum.

The Genital Ducts of Theodoxus, Lamellaria and Trivia, and a Discussion on their Evolution in the Prosobranchs

The prosobranchiate gastropods are divided into three orders, the Archaeogastropoda, the Mesogastropoda and the Stenoglossa. In the first of these groups the gonad is connected with the right kidney by a duct which is developed from the ovary, and the sex cells escape to the posterior end of the mantle cavity through the right ureter. The eggs are usually shed singly into the sea where fertilization occurs. In the Mesogastropoda and Stenoglossa the right kidney is not developed and the ovarian duct leads to a short and narrow section of the genital duct which is typically ciliated, and may communicate with the pericardium by a gonopericardial duct and passes anteriorly to a long glandular tract running forwards to the mouth of the mantle cavity. This glandular section is incipient in the archaeogastropod Calliostoma zizyphinum. It is probably formed, as Thiele (1935) suggests, by an ectodermal intucking and will be referred to as the pallial oviduct, for it lies anterior to the opening of the original right kidney, and must be derived from the ectoderm of the mantle (Bourne, 1908; Giese, 1915). The short duct which links it with the ovarian duct will be termed the renal oviduct: in Paludina (=Viviparus), in which its development has been investigated (Drummond, 1903), it is formed from the vestige of the right kidney, and even in the highly specialized Stenoglossa it retains the connexion with the pericardium which is characteristic of the right and left kidneys of the archaeogastropods. Similarly, in the male system of the Mesogastropoda and Stenoglossa there can be distinguished a testis duct, which is connected to the posterior end of the mantle cavity by a renal vas deferens, and this in turn is followed by a pallial vas deferens.