Charonia

Abstract: This paper is the first to describe, in detail, the process of feeding by a species of Charonia. As Charonia lampas commenced attacking its sea star prey, Ophidiaster ophidianus, the latter autotomized its trailing arm and escaped. The pursuing C. lampas ate this arm. The results of this study are not in accord with the established view of feeding by species of Charonia. Firstly, C. lampas did not inject either a venom into its prey to paralyse it nor an acid to access it and, second, nor did it pierce the skeleton of its prey and suck out the tissues, all as reported in the literature. Rather, in the case herein described, C. lampas held and manipulated its prey with the foot and used its taenioglossan radula located at the end of the extendible pleurembolic proboscis to scrape and ingest the soft tissues of the sea star and, subsequently, consume the remaining skeletal components again using the proboscis and contained radula. These two phases of consumption were followed by two matching phases of faece...

Abstract: The stabilisation of strong textures in mollusc shells has for long been a strong drawback towards precise structural determinations of these natural biocomposites. We demonstrate here on several crossed lamellar and nacre layers from two gastropods (Charonia lampas lampas and Haliotis tuberculata tuberculata) and one bivalve (Pinctada maxima), that on real specimens (without grinding or specific preparation), the textural information can be used efficiently for precise structural determination of the biogenic aragonite. This is done through the combination of orientation distribution function and cyclic Rietveld refinements on several hundreds to thousands of diffractions diagrams.

Abstract: The triton Charonia seguenzae (Aradas & Benoit, 1870), formerly reported as C. variegata (e.g. Clench & Turner, 1957) or C. tritonis variegata (e.g. Beu, 1970), has only recently been considered as a separate species restricted to the eastern Mediterranean Sea (Beu, 2010). Information on this species is scarce and mostly concerns geographical distribution and taxonomy (Beu, 2010). Complementary literature on Charonia from the Indo-Pacific region provides some biochemical and pharmacological data (Teshima et al., 1979) and reports of feeding behaviour (Laxton, 1971; Kang & Kim, 2004). Collection for the international shell trade has contributed to the overfishing and depletion of many triton populations worldwide (Katsanevakis et al., 2008). Nowadays, both Charonia species in the Mediterranean are protected according to Annex II of the Bern convention (Council of Europe, 1979) and the protocol of the Barcelona convention (European Community, 1999). Reestablishment of Charonia populations in depleted areas requires knowledge of its biology and ecology and potentially can be enhanced by information on maintenance and breeding in captivity. Lacking information about C. seguenzae, Russo et al. (1990) hypothesized that its life habits should be similar to the Mediterranean C. lampas. It has been assumed that, in the wild, C. sequenzae is a selective feeder with a diet based mainly on live echinoderms (Russo et al., 1990), of which sea stars are the most preferred (Doxa et al., 2006). The objective of this study was to quantify for first time the food acceptability of six species of natural prey and nine species of commercially available possible alternative food for C. seguenzae. Experiments were conducted at the facilities of Cretaquarium, a public aquarium of the Hellenic Centre for Marine Research (HCMR). During 2009, nine wild adults of C. seguenzae (631.6+24.6 g weight) were collected by Scuba diving from inshore waters of Crete, Greece, and transported to Cretaquarium. They were measured (shell length, SL), weighed (W), marked (shell engraved with Dremel trepan 400 Digital) and placed in 150-l aquaria, where they remained for quarantine and adaptation for 1 year before the experiment. During this period, food was provided once a week and consisted of frozen sea stars and fish, and of live sea urchins and holothurians. Aquariums were organized as semiclosed circuits with mechanical aeration and biological filtration. They were filled with seawater from a deep circumlittoral borehole. Water renewal and recirculation rates were, respectively, 30 and 100%/h. Illumination was provided by white 60-W neon lamps. Photoperiod was artificially adjusted to 12L:12D. Temperature, salinity, oxygen saturation and pH remained constant at 23.15+0.18C, 35, 90% and 7.7+0.1, respectively. Food acceptability of six echinoderm species (seastars: Astropecten aranciacus, Marthasterias glacialis, Luidia sarsi; sea urchins: Arbacia lixula, Paracentrotus lividus; sea cucumber: Holothuria forskali), three fish species (Boops boops, Merluccius merluccius, Sardina pilchardus), four mollusc species (Sepia officinalis, Octopus vulgaris, Nototodarus sloanii, Mytilus chilensis) and two crustacean species (Parapenaeus longirostris, Nephrops norvegicus) was studied. The echinoderms were collected from inshore littoral waters of Crete and stored deep frozen (2208C), while the remaining species were purchased from the local market. The specimens were individually placed in 150-l aquaria under similar conditions to those described above. Each food was tested on three animals, through six acceptability trials per animal, with a fasting period of 1 week between the different foods. For the trials, each animal was provided every 2 d with a weighed quantity of defrosted food, allowed to consume for 24 h, and then the remaining food was collected and weighted. The rate of successful trials (when food was consumed) and food consumption per trial were calculated. The time needed for animals to respond to the presence of food (response time, RT) and to approach it (approach time, AT) were recorded. Data were analysed for normality (Kolomogorov–Smirnov test) and homoscedascity of variance (Bartlett’s test of sphericity). One-way analysis of variance (ANOVA) was used to test for significant differences in acceptability for the 15 different foods. If significant (P, 0.05), Tukey’s multiple-comparison test was applied to identify groups that were significantly different. All foods offered were consumed (Fig. 1A), with the highest consumption rates for Marthasterias (48.16+3.94 g) and Astropecten (42.43+3.94 g). High consumption rates were also recorded for Boops (19.11+ 2.05 g), Merluccius (18.67+ 4.79 g) and Nephrops (17.12+2.7 g), which showed values exceeding