ALBERT

Description: It is well known that land snails can be dispersed by birds, both by attachment to the body (ectozoochory) and by passing intact and alive through the bird's digestive tract (endozoochory). Endozoochory has, however, only been recorded for very small species. We examined the possibility that larger species (up to c . 17 mm in maximum shell dimension) could survive passage through a bird's digestive system. Live Alinda biplicata , Cochlodina laminata (both Clausiliidae) and Discus rotundatus (Discidae) were fed to 10 bird species (Corvidae, Turdidae, Sturnidae and Columbidae) in 14 experimental trials. Of 720 snails offered, 14 passed intact through the birds, of which nine were alive (eight clausiliids and one D. rotundatus ); thus more than 1% of all snails offered survived ingestion. In an additional experiment, some A. biplicata and C. laminata remained attached to birds' legs by pedal adhesion in simulated flight trials where the birds' legs oscillated at the maximum rate achieved during flight.

Description: Cephalopods show excellent camouflaged body patterning, but they also use body patterning for communication. It is not known whether body patterning responses can be shaped by learning. Here, we tested the hypothesis that cuttlefish ( Sepia officinalis ) can be conditioned to change their body pattern for a food reward. Cuttlefish were placed in a tank (all black or all white) and allowed to acclimate and settle into camouflaged body patterning (matching the tank colour). In each trial, a contrasting probe (white or black) was inserted into the tank. Experimental cuttlefish received a food reward if they broke camouflage (e.g. displayed light body patterning in the black tank or displayed dark body patterning in the white tank) within 15 s of the insertion of the probe; control cuttlefish received food rewards at random intervals. Experimental cuttlefish changed their body patterning more quickly and more consistently in response to the probe than did control cuttlefish, but only when they were trained in the black tank. We conclude that cuttlefish body patterning is not entirely innate, can be shaped by individual experience and appears to be more flexible than previous research has suggested.

Description: Snail shells represent an abundant source of information about the organisms that build them, which is particularly vital and relevant for species that are locally or globally extinct. Access to genetic information from snail shells can be valuable, yet previous protocols for extraction of DNA from empty shells have met with extremely low success rates, particularly from shells weathered from long-term exposure to environmental conditions. Here we present two simple protocols for the extraction and amplification of DNA from empty land snail shells from specimens of Galápagos endemic snails, including presumably extinct species. We processed 35 shells of the genus Naesiotus (Bulimulidae) from the Galápagos islands, some from species that have not been observed alive in the past 50 years. We amplified and sequenced short fragments (≤244 bp) of mitochondrial DNA (mtDNA) from 18 specimens. Our results indicate that the implementation of an ancient DNA extraction protocol and careful primer design to target short DNA fragments can result in successful recovery of mtDNA data from such specimens.

Description: The present study focuses on two apparent species: the giant thyasirid Conchocele bisecta (Conrad, 1849), which is the dominant species of the benthic community in a gas hydrate area with cold-water methane-rich vents at a depth of about 800 m on the slope off Paramushir Island (Kuril Islands, Sea of Okhotsk) and small unidentified thyasirid bivalves from this same community. An examination of the shell morphology of these thyasirids showed that the small bivalves were in fact young specimens of C. bisecta , characterized by a high individual and age variability. A transmission electron microscopic study of C. bisecta revealed gills with ‘Type 3’ filaments, which were extended abfrontally and had a distinct bacteriocyte zone with extracellular symbionts. The symbiotic bacteria found were spherical, similar to thiotrophic symbionts of other thyasirids. The isotopic 13 C values of C. bisecta soft tissues (from –39.6 to –33.8) were much heavier than those of methane in the Paramushir gas-hydrate area and matched the range characteristic of symbiotrophic bivalves harbouring sulphur-oxidizing chemoautotrophic bacteria. The variations in 13 C and 15 N recorded for large and small C. bisecta can be related to ontogenetic differences in life habit: small individuals are totally buried in the sediment, while large ones are half-buried. Data from fatty acid (FA) analysis indicate that sulphur-oxidizing symbionts constitute almost the entire nutrition of C. bisecta , with no significant contribution of symbiotic or free-living methanotrophs . Furthermore, neither FA nor isotopic compositions provided evidence for photosynthetic sources as food items for C. bisecta through filter feeding.

Description: The genus Liocarenus (Acteonidae) was originally described from Eocene fossil material and has subsequently come to include three subgenera ( Liocarenus s. s ., Bulimactaeon and Nucleopsis ) and nine species, including a Recent one ( L. globulinus ). Together, these have been accorded status as a subfamily, Liocareninae. We here present a taxonomic revision of all the species and subgenera historically ascribed to Liocarenus . We show that the genus name Liocarenus is an objective synonym of Hemiauricula . All three taxa ( Bulimactaeon , Hemiauricula and Nucleopsis ) are accepted at genus level and a new genus, Rapturella , is erected for the Recent species. Rapturella is diagnosed by a thick shell with rounded whorls, slightly stepped spire, two closely spaced subsutural spiral grooves, a weak columellar fold and a tooth-like palatal thickening. Three of the formerly included species of Liocarenus are here excluded from the Acteonidae. The revised classification is as follows: B. bernayi (Cossmann, 1892), H. edentula (Férussac, 1821), H. hilarionis (Bayan, 1870) n. comb., N. subvaricatus (Conrad, 1860), R. globulina (Forbes, 1844) n. comb. and R. ryani n. sp. (Acteonidae); Hamlinia eliai (Shalem, 1928) n. comb. and Globiconcha formosa (Cragin, 1893) n. comb. (Cylindrobullinidae); Ringicula lata (Conrad, 1865) n. comb. (Ringiculidae). Acteon costellatus Conrad, 1833 is considered a species inquirenda .

Description: Muricanthus fulvescens , one of the largest muricid gastropods in the world, was once thought to be a behavioural specialist, using its shell to grind feeding holes in bivalve prey. New experimental observations, however, reveal that this predator employs up to four modes of predation, including selective use of shell grinding and edge drilling in interactions with the large, thick-shelled venerid clam Mercenaria campechiensis . Shell-grinding attacks were found to be slightly faster than edge-drilling attacks, but had a lower success rate. Choice of predatory mode was more strongly correlated with the prey's anterior–posterior shell length than predator size. Smaller clams were attacked more frequently by shell grinding, while larger, thicker prey tended to be attacked by edge drilling. Several larger predators edge-drilled their prey successfully after first failing with the faster grinding behaviour; trial-and-error initiation of attacks with the more rapid grinding behaviour, however, was rare and expressed only by the largest predators. We also report an anecdotal observation of wall drilling and morphological evidence consistent with two modes of edge-drilling attacks, including drilling of larger holes for proboscis insertion and feeding and smaller, barely detectable (〈1 mm) holes for toxin injection. Toxin use is further supported by a lack of correlation between predator size and inner drill-hole dimensions. The occurrence of previously undetected diversity in predatory modes of M. fulvescens , a common, easily accessible species, demonstrates how much we have to learn about ecological versatility in muricids and its role in muricid evolution.

Description: The microanatomy of Ventsia tricarinata Warén & Bouchet, 1993 , a small coiled ‘skeneimorph’ gastropod from Pacific hydrothermal vents, is described based on computer-aided reconstructions of semithin section series and visualized by interactive 3D-modelling. This is the most complete account of the anatomy and histology of a seguenzioid vetigastropod presented to date, although details of the male genital system could not be detected. This species was placed originally in the Skeneidae (Trochoidea), but molecular data subsequently suggested a basal seguenzioidean position. The latter hypothesis is supported herein by morphological data, in particular by the conditions of the right neck (with two tentacles), the epipodium (with separated epipodial sense organs) and the bipartite seminal receptacle with concentric arrangement of sperm in its posterior part on the left side of the mantle roof.

Description: High levels of biodiversity and phylogeographic structure in marine species in Southeast Asia are strongly linked to Quaternary sea-level fluctuations and complex oceanographic conditions. Cellana toreuma is a common limpet on intertidal rocky shores and is widely distributed in the Western Pacific. Analyses of partial mitochondrial COI gene sequences from Southeast Asia, combined with previously published sequences from East Asia and Indonesia, revealed the existence of five well-supported clades with high genetic divergences (between 1.4 and 7.6%), namely the East Asia clade, the eastern Southeast Asia clade, the western Southeast Asia clade, the Pelabuan Ratu (Java) clade and the Ogasawara clade. The geographical distribution of the five clades is likely related to the history of glaciations and rapid postglacial population expansions. Analyses of pairwise ST and hierarchical analysis of molecular variance shows significant population structure among collections in East and Southeast Asia. These results suggest that historical events have had strong effects on the phylogeographic structure of C. toreuma . In addition, present environmental factors, such as unsuitable habitats and ocean currents, have also affected the genetic footprints of past environments.

Description: Information on the genetic population structure of endangered giant clams is important for conservation programmes and the understanding of ecological and evolutionary processes. In this study, the genetic population structures of three codistributed and ecologically similar giant clam species ( Tridacna crocea , T. maxima and T. squamosa ) are compared. A fragment of the cytochrome c oxidase I gene was sequenced as a genetic marker in three giant clam species sampled throughout the Indo-West Pacific, from the Western Indian Ocean (WIO) and Red Sea (RS) to the Eastern Indian Ocean (EIO), across the centre of marine biodiversity in the Indo-Malay Archipelago (IMA) to the Western Pacific (WP) and the Society Islands in the Central Pacific (CP). All three species showed limited gene flow and a highly significant genetic population structure. The st -values ( P 〈 0.001) are 0.46, 0.81 and 0.68 for T. crocea , T. maxima and T. squamosa , respectively. Based on a hierarchical AMOVA they could be divided into three to six groups from West to East: (1) WIO ( T. maxima and T. squamosa ), (2) RS ( T. maxima and T. squamosa ), (3) EIO (including Java Sea in T. maxima ), (4) central IMA, (5) WP and (6) CP ( T. maxima ). The distribution of the haplotype clades in the populations and the pairwise st -values between populations indicated a high level of gene flow in the central IMA for the three species. The concordant patterns suggest that geological history, sea-level changes during glacial periods of the Pliocene and Pleistocene, and oceanography are important factors shaping the genetic population structure of giant clams. The observed deep evolutionary lineages in the peripheral areas of the IMA might include cryptic species.

Description: Attaching objects to bivalve shells is an increasing requirement for conservation projects, mark-recapture studies and behavioural analysis. We investigated the suitability of eight different glues to attach a metallic object to a mussel shell and confirmed the utility of the best glue in a filtration behaviour experiment using Anodonta anatina . We used removal forces up to 1.35 kg cm –2 7 d after submerging in water and found an epoxy resin and a cyanoacrylate adhesive to perform best. Not all epoxy resins or cyanoacrylate adhesives performed equally. The best performing cyanoacrylate adhesive was used to glue magnets and rubber-coated Hall sensors to 26 mussels for a filtration-behaviour experiment. Nine months after attachment, all magnets and rubber-coated Hall sensors remained attached and withstood 1.35 kg cm –2 . The epoxy resin was not chosen, because it contained Bisphenol A and required a more complex application procedure. Mussel filtration behaviours were monitored for 96 h in the presence of algae. The results showed that the presence of algae stimulated the filtration rate of A. anatina in the first 24 h. Over the experimental period, the mussels' mean filtration duration was 20 ± 12 h, while the resting duration was 16 ± 7 h. We identified a pronounced circadian rhythm, despite the long filtration duration and variation in behaviour patterns. However, at any one time some mussels were observed to be filtering. The mussels were more likely to open their shells and become active at around 20:00. Thus the majority of mussels were active at midnight and a minority at noon. We interpret the strong response to increased algal concentration and the pronounced circadian rhythm as evidence that neither the glue nor the attached sensors disturbed the mussels even in a short-term experiment. Hence, we recommend the selected cyanoacrylate adhesive for use in tagging projects and behavioural studies of freshwater mussels.