Journal articles: 'Gastropod molluscs'

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Dharma, Bunjamin. "Molluscs Combing on The Coast of Karang Hawu, West Java." Jurnal Moluska Indonesia 4, no. 1 (April 1, 2020): 17–26. http://dx.doi.org/10.54115/jmi.v4i1.24.

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Karang Hawu Beach faces the Indian Ocean, so the presence of mollusks in the area varies widely and can increase in variety due to natural phenomena, such as earthquakes and tsunami outbreaks. The research objective was to obtain gastropods and bivalves (mollusks) by sweeping the Karang Hawu beach, West Java. Samples were collected from the coastal waters of Karang Hawu, West Java using the coastal sweeping method, then the samples were identified. The results showed that there were 3 classes of mollusks, namely: Cephalopod class, Bivalvia class, and Gastropod class with 42 families and 146 species of mollusks. Mollusks, with the highest gastropod class (38 families, 140 species), Bilavia class (3 families, 5 species), and Cephalopod class (1 family, 1 species). Results of the study concluded that based on the Molluscs sweeping the coast of Karang Hawu, West Java, it has a diversity of Molluscs, namely 146 species of mollusks from 3 classes, which were Gastropods, Bivalves, and Cephalopods.

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Stewart, Sarah E. "Distribution and palaeoecology of Ordovician bivalves and gastropods from Girvan, SW Scotland." Earth and Environmental Science Transactions of the Royal Society of Edinburgh 102, no. 3 (August 15, 2012): 145–58. http://dx.doi.org/10.1017/s175569101201002x.

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ABSTRACTMolluscs from the Middle and Upper Ordovician succession of Girvan, SW Scotland are common and diverse in some localities. The mollusc fauna consists mainly of gastropods, bivalves and various univalved molluscs (mimospirids and tergomyans), along with scarcer polyplacophorans, rostroconchs and cephalopods. The present study gives an overview of the distribution and palaeoecology of bivalves, gastropods and univalved molluscs and compares them with mollusc faunas worldwide. Gastropods, mimospirids and tergomyans are present from the Darriwilian (mid Llanvirn) onwards in both siliciclastic and carbonate facies, and increase in diversity through the Sandbian (Caradoc) and into the Katian (Ashgill). Bivalves first appeared in Girvan in the late Darriwilian (early Caradoc) in deep water siliciclastic facies; where they continued to be more abundant and diverse than in equivalent carbonate facies. Molluscs are initially Laurentian in aspect, though peri-Gondwanan faunal elements occur, particularly during the Sandbian. The pattern of bivalve and gastropod diversity found in the Ordovician of Girvan generally follows that of the known global diversity for these groups.

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Huan, Pin, Qian Wang, Sujian Tan, and Baozhong Liu. "Dorsoventral decoupling of Hox gene expression underpins the diversification of molluscs." Proceedings of the National Academy of Sciences 117, no. 1 (December 23, 2019): 503–12. http://dx.doi.org/10.1073/pnas.1907328117.

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In contrast to the Hox genes in arthropods and vertebrates, those in molluscs show diverse expression patterns with differences reported among lineages. Here, we investigate 2 phylogenetically distant molluscs, a gastropod and a polyplacophoran, and show that the Hox expression in both species can be divided into 2 categories. The Hox expression in the ventral ectoderm generally shows a canonical staggered pattern comparable to the patterns of other bilaterians and likely contributes to ventral patterning, such as neurogenesis. The other category of Hox expression on the dorsal side is strongly correlated with shell formation and exhibits lineage-specific characteristics in each class of mollusc. This generalized model of decoupled dorsoventral Hox expression is compatible with known Hox expression data from other molluscan lineages and may represent a key characteristic of molluscan Hox expression. These results support the concept of widespread staggered Hox expression in Mollusca and reveal aspects that may be related to the evolutionary diversification of molluscs. We propose that dorsoventral decoupling of Hox expression allowed lineage-specific dorsal and ventral patterning, which may have facilitated the evolution of diverse body plans in different molluscan lineages.

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Kobluk, David R., and Mary A. Lysenko. "Hurricane effects on shallow-water cryptic reef molluscs, Fiji Islands." Journal of Paleontology 67, no. 5 (September 1993): 798–816. http://dx.doi.org/10.1017/s0022336000037069.

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An assemblage of 343 species of cryptic, shelled molluscs was identified in three large samples from shallow subtidal and intertidal shelter habitats under rubble and corals at Malololailai Fiji in 1983, 1984, and 1985. One species was a polyplacophoran, 273 were gastropods (38 families), and 69 were bivalves (21 families). Cryptic gastropods were more abundant than bivalves, but showed a reduction in abundance relative to bivalves from 1983 to 1985. The abundances of many cryptic molluscs show dramatic adjustments from 1983 to 1985, chiefly due to hurricanes in 1983 and 1985, showing a decrease in equitability with increased physical disturbance. The abundance and diversity of molluscan predators in the crypts means that predation in these habitats may be substantial.The gastropod sample diversity showed the greatest change during the 1984 post-hurricane recovery period. The 1985 hurricanes affected the sample diversity by shifting the gastropod diversity closer to what it was after the 1983 hurricane. The bivalves underwent a similar shift in sample diversity, although larger numbers of individuals in proportionately more species survived the hurricanes.The cryptic bivalves exploited space in new crypts, while maintaining their rate of increase in abundance in the recovery period after the 1983 hurricane and through the two hurricanes in 1985. The gastropods declined in abundance after the 1983 hurricane. They recovered after the 1985 hurricanes by doubling their abundance, showing that they could exploit new resources in crypts. This increase in the gastropod population was not proportional to the increase in available cryptic space. This may mean they were still recovering in August 1985, or they may have been unable to capture their portion of cryptic space in competition with other organisms during recovery.The 1985 hurricanes did not have much effect on the overall molluscan diversity, a possible result of pruning by the 1983 hurricane of molluscs unable to survive storms. Because there was only a short interval between the hurricanes, many molluscs that survived the 1983 event were still in the population, so that the cryptic molluscs probably were better able to deal with the effects of the 1985 hurricanes than they would have been before the 1983 hurricane. The result was that the sample diversity after the 1983 hurricane increased during the recovery period but did not decline later even though the population was devastated by hurricanes in 1985. This lends support to intermediate disturbance models linking increasing or stable diversity with disturbances spaced at intervals allowing recovery.

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Izzatullaev, Zuvaidullo I., and Nilufar A. Ruzikulova. "Особенности экологии и жизненных циклов водных моллюсков Средней Азии." Бюллетень Дальневосточного малакологического общества 24, no. 1/2 (2020): 37–52. http://dx.doi.org/10.24866/1560-8425/2020-24/37-52.

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Рассмотрены особенности экологии водных моллюсков Средней Азии. Представлены оригинальные сведения по биологии 45 видов брюхоногих и двустворчатых моллюсков. Обсуждается влияние на жизненные циклы этих видов температуры, кислородного режима, освещенности, продолжительности безводного периода. Показана прямая зависимость между размерами моллюсков и продолжительностью их жизни. Ключевые слова: Средняя Азия, брюхоногие, двустворчатые моллюски, экологические группы, жизненный цикл, продолжительность жизни, размножение, генерация. Ecological patterns of aquatic mollusks of Central Asia are discussed and reviewed. Original data on biology of 45 gastropod and bivalve species are presented. The effect of temperature, oxygen regime, illumination and duration of waterless periods on mollusk life cycles is discussed. A direct relationship has been shown between the size of molluscs and their lifespan. Key words: Central Asia, gastropods, bivalves, ecological groups, life cycle, lifespan, reproduction, generation.

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Aji, Ludi Parwadani, and Andriani Widyastuti. "Molluscs Diversity in Coastal Ecosystem of South Biak, Papua." Oseanologi dan Limnologi di Indonesia 2, no. 1 (May 5, 2017): 25. http://dx.doi.org/10.14203/oldi.2017.v2i1.75.

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Coastal areas of Biak Island consist of three major ecosystems: the mangrove, seagrass beds, and coral reefs where a variety of molluscs live. Mollusc diversity in South Biak waters was investigated in September 2011. The observation was conducted at 4 locations, i.e. Paray, Ambroben, Yenures, and Sorido with 2 stations at each location. The study aimed to obtain information on the diversity and community structure of the benthic molluscs (gastropods and bivalves) on the coastal areas of South Biak waters. Sampling method applied was quadrate-transect line in intertidal areas from inshore to offshore. The molluscs (epifauna and infauna) found inside the quadrate-transect were counted and identified. The result showed high benthic mollusc diversity with a total of 94 species, consisting of 75 species of gastropods and 19 species of bivalves. The most widespread gastropod found in all stations was Nassarius sp., while for bivalves was Tellina sp. The highest value of diversity index (H) was 2.96 found in Paray 1 and the lowest was 0.58 in Yenures 1. The Evenness index (E) and Simpson index (D) ranged from 0.27 to 0.96 and from 0.06 to 0.72 respectively. Species richness (d) ranged from 2.89 to 6.84 and similarity index from 3.90 to 42.40.

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Zapata, Felipe, Nerida G. Wilson, Mark Howison, Sónia C. S. Andrade, Katharina M. Jörger, Michael Schrödl, Freya E. Goetz, Gonzalo Giribet, and Casey W. Dunn. "Phylogenomic analyses of deep gastropod relationships reject Orthogastropoda." Proceedings of the Royal Society B: Biological Sciences 281, no. 1794 (November 7, 2014): 20141739. http://dx.doi.org/10.1098/rspb.2014.1739.

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Gastropods are a highly diverse clade of molluscs that includes many familiar animals, such as limpets, snails, slugs and sea slugs. It is one of the most abundant groups of animals in the sea and the only molluscan lineage that has successfully colonized land. Yet the relationships among and within its constituent clades have remained in flux for over a century of morphological, anatomical and molecular study. Here, we re-evaluate gastropod phylogenetic relationships by collecting new transcriptome data for 40 species and analysing them in combination with publicly available genomes and transcriptomes. Our datasets include all five main gastropod clades: Patellogastropoda, Vetigastropoda, Neritimorpha, Caenogastropoda and Heterobranchia. We use two different methods to assign orthology, subsample each of these matrices into three increasingly dense subsets, and analyse all six of these supermatrices with two different models of molecular evolution. All 12 analyses yield the same unrooted network connecting the five major gastropod lineages. This reduces deep gastropod phylogeny to three alternative rooting hypotheses. These results reject the prevalent hypothesis of gastropod phylogeny, Orthogastropoda. Our dated tree is congruent with a possible end-Permian recovery of some gastropod clades, namely Caenogastropoda and some Heterobranchia subclades.

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Donnarumma, Luigia, Roberto Sandulli, Luca Appolloni, José Sánchez-Lizaso, and Giovanni Russo. "Assessment of Structural and Functional Diversity of Mollusc Assemblages within Vermetid Bioconstructions." Diversity 10, no. 3 (August 28, 2018): 96. http://dx.doi.org/10.3390/d10030096.

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Dendropoma lebeche is a prosobranch gastropod belonging to the family Vermetidae, which calcifies its shell on hard substrates in dense aggregates, forming biogenic constructions along the western Mediterranean intertidal habitat. It is an important ecosystem engineer and, due to its ecological value, is protected by international convention. The aim of this study is to investigate the mollusc composition and diversity occurring within Spanish vermetid bioconstructions. During the late summer 2013, three distant sites along the Mediterranean coast of Spain were sampled by scraping off the vermetid shells to study their associated assemblages. A total of 600 molluscs were identified within the classes of Polyplacophora (four species), Gastropoda (35 spp.) and Bivalvia (18 spp.). Multivariate analyses revealed significant differences in composition and trophic diversity of mollusc assemblages among the three sites, highlighting a clear geographical gradient. Overall, both herbivores (grazers and deposit feeders) and omnivores were the quantitatively dominant trophic groups, while carnivores (predators and ectoparasites) were very scarce. Our results point out that mollusc assemblages associated with vermetid bioconstructions are rich and diversified, both in populations structure and trophic diversity, confirming the important role of vermetid gastropods as ecosystem engineers and biodiversity enhancers in shallow coastal waters.

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HODGSON, A. N. "Paraspermatogenesis in gastropod molluscs." Invertebrate Reproduction & Development 31, no. 1-3 (January 1997): 31–38. http://dx.doi.org/10.1080/07924259.1997.9672560.

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Shepeleva, I. P. "Vitreous body of the camera-like eyes of terrestrial gastropod mollusks (Heterobranchia, Stylommatophora)." Ruthenica, Russian Malacological Journal 31, no. 2 (April 1, 2021): 93–104. http://dx.doi.org/10.35885/ruthenica.2021.31(2).5.

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Using the methods of light and electron microscopy, the morphological properties were studied, and the evolutionary changes in the vitreous body of the camera-like eyes of some species of terrestrial gastropod pulmonate molluscs were traced. It was demonstrated that all the considered properties of the vitreous body of molluscs are typical for terrestrial pulmonates. In the course of evolution, as a result of the land development by mollusks, the properties of their vitreous body have hardly changed.

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Yoshino, T. P., U. Bickham, and C. J. Bayne. "Molluscan cells in culture: primary cell cultures and cell lines." Canadian Journal of Zoology 91, no. 6 (June 2013): 391–404. http://dx.doi.org/10.1139/cjz-2012-0258.

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In vitro cell culture systems from molluscs have significantly contributed to our basic understanding of complex physiological processes occurring within or between tissue-specific cells, yielding information unattainable using intact animal models. In vitro cultures of neuronal cells from gastropods show how simplified cell models can inform our understanding of complex networks in intact organisms. Primary cell cultures from marine and freshwater bivalve and gastropod species are used as biomonitors for environmental contaminants, as models for gene transfer technologies, and for studies of innate immunity and neoplastic disease. Despite efforts to isolate proliferative cell lines from molluscs, the snail Biomphalaria glabrata (Say, 1818) embryonic (Bge) cell line is the only existing cell line originating from any molluscan species. Taking an organ systems approach, this review summarizes efforts to establish molluscan cell cultures and describes the varied applications of primary cell cultures in research. Because of the unique status of the Bge cell line, an account is presented of the establishment of this cell line, and of how these cells have contributed to our understanding of snail host – parasite interactions. Finally, we detail the difficulties commonly encountered in efforts to establish cell lines from molluscs and discuss how these difficulties might be overcome.

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Elliott, C. J. H., and A. J. Susswein. "Comparative neuroethology of feeding control in molluscs." Journal of Experimental Biology 205, no. 7 (April 1, 2002): 877–96. http://dx.doi.org/10.1242/jeb.205.7.877.

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SUMMARY Over the last 30 years, many laboratories have examined, in parallel, the feeding behaviour of gastropod molluscs and the properties of the nervous system that give rise to this behaviour. Equal attention to both behavioural and neurobiological issues has provided deep insight into the functioning of the nervous system in generating and controlling behaviour. The conclusions derived from studies on gastropod feeding are generally consistent with those from other systems, but often provide more detailed information on the behavioural function of a particular property of the nervous system. A review of the literature on gastropod feeding illustrates a number of important messages. (i) Many of the herbivorous gastropods display similarities in behaviour that are reflected in corresponding similarities in neural anatomy,pharmacology and physiology. By contrast, the same aspects of the behaviour of different carnivorous species are quite variable, possibly because of their specialised prey-capture techniques. Nonetheless, some aspects of the neural control of feeding are preserved. (ii) Feeding in all species is flexible,with the behaviour and the physiology adapting to changes in the current environment and internal state and as a result of past experience. Flexibility arises via processes that may take place at many neural sites, and much of the modulation underlying behavioural flexibility is understood at a systems and at a cellular level. (iii) Neurones seem to have specific functions that are consistent with their endogenous properties and their synaptic connections, suggesting that individual neurones code specific pieces of information (i.e. they are `grandmother cells'). However, the properties of a neurone can be extremely complex and can be understood only in the context of the complete neural circuit and the behaviour that it controls. In systems that are orders of magnitude more complex, it would be impossible to understand the functional properties of an individual neurone, even if it also coded specific information. (iv) Systems such as gastropod feeding may provide a model for understanding the functional properties of more complex systems.

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PONNUSAMI, JAYASRI, and FAZIMAH AZIZ. "Checklist of Molluscs (Gastropoda and Bivalvia) of Malaysia Exclusive Economic Zone (EEZ) in Sarawak Waters." Borneo Journal of Resource Science and Technology 7, no. 2 (December 28, 2017): 111–17. http://dx.doi.org/10.33736/bjrst.597.2017.

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Most of the molluscs studies in Malaysia have focused only on their diversity and the knowledge on their relationship with the water depth are lacking. The hypothesis tested in this research was water depth influence the density of marine gastropods and bivalves of Malaysia Exclusive Economic Zone (EEZ) in Sarawak waters. The aim of the study was to determine the gastropod and bivalve species in Malaysia EEZ of Sarawak waters and the relationship of the species density with water depth. The sampling was conducted from 15th August 2015 until 9th October 2015. The gastropods and bivalves were collected from 32 stations of various depths using the Smith-McIntyre grab. The depth of the stations was from 20 m to 200 m. A total of 95 taxa (61 Gastropoda and 34 Bivalvia) were found in this study. The dominant molluscs species of Sarawak waters in Malaysia EEZ were Limopsis sp., Turitella cingulifera, Pitar citrinus, and Cavolinia globulosa. Species density was about 10 ind./m2 to 610 ind./m2 and the total density was between 250 ind./m2 (Station 22) and 1,940 ind./m2 (Station 2). The total density of gastropods and bivalves showed weak correlation and negative relationship with the depth of water. The findings of this study will aid future studies in Malaysia EEZ. Keywords: Bivalves, gastropods, Malaysia EEZ, Sarawak waters

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PONNUSAMI, JAYASRI, and FAZIMAH AZIZ. "Supplementary Materials: Checklist of Molluscs (Gastropoda and Bivalvia) of Malaysia Exclusive Economic Zone (EEZ) in Sarawak Waters." Borneo Journal of Resource Science and Technology 7, no. 2 (December 28, 2017): 111–17. http://dx.doi.org/10.33736/bjrst.598.2017.

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Most of the molluscs studies in Malaysia have focused only on their diversity and the knowledge on their relationship with the water depth are lacking. The hypothesis tested in this research was water depth influence the density of marine gastropods and bivalves of Malaysia Exclusive Economic Zone (EEZ) in Sarawak waters. The aim of the study was to determine the gastropod and bivalve species in Malaysia EEZ of Sarawak waters and the relationship of the species density with water depth. The sampling was conducted from 15th August 2015 until 9th October 2015. The gastropods and bivalves were collected from 32 stations of various depths using the Smith-McIntyre grab. The depth of the stations was from 20 m to 200 m. A total of 95 taxa (61 Gastropoda and 34 Bivalvia) were found in this study. The dominant molluscs species of Sarawak waters in Malaysia EEZ were Limopsis sp., Turitella cingulifera, Pitar citrinus, and Cavolinia globulosa. Species density was about 10 ind./m2 to 610 ind./m2 and the total density was between 250 ind./m2 (Station 22) and 1,940 ind./m2 (Station 2). The total density of gastropods and bivalves showed weak correlation and negative relationship with the depth of water. The findings of this study will aid future studies in Malaysia EEZ. Keywords: Bivalves, gastropods, Malaysia EEZ, Sarawak waters

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Tolhurst, Bryony A., Andrew D. J. Overall, Peter J. King, Eric R. Morgan, and Rowenna J. Baker. "Co-Occurrence of Domestic Dogs and Gastropod Molluscs in Public Dog-Walking Spaces and Implications for Infection with Angiostrongylus vasorum: A Preliminary Study." Animals 11, no. 9 (September 2, 2021): 2577. http://dx.doi.org/10.3390/ani11092577.

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Angiostrongylusvasorum is a helminth parasite of domestic dogs that is increasing in range and prevalence. Its lifecycle requires terrestrial gastropod mollusc (“gastropod”) intermediate hosts, but research is lacking regarding contact risk in situ. We studied co-occurrence between dogs and gastropods in dog-walking spaces in an A. vasorum hotspot in southern England, United Kingdom, with the aim of quantifying environmental and spatio-temporal overlap. We surveyed 390 quadrats and 180 point-counts along 3 km transects at seven sites, yielding 1672 gastropod and 763 dog observations. Common gastropods comprised Arion, Cornu, Monacha, Deroceras, Tandonia, Cochlicella, and Trochulus species. Habitat was the most important factor structuring both gastropod and dog presence and abundance. Likelihood ratio comparisons from conditional probability trees revealed that dogs were 15× more likely to be present on hardstanding surfaces than other habitats but were also present on natural and amenity grassland. Presence of gastropod species associated with high A. vasorum prevalence was 65.12× more likely in woodland/scrub and 62.17× more likely in amenity grassland than other habitats. For gastropods overall, high abundance was 5.82× more likely in woodland/scrub and natural grassland. The findings suggest co-occurrence is highest in amenity and natural grassland, but infection risk is greatest in amenity grassland and woodland/scrub.

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Fiore, Lorenzo. "Neuroethological studies on gastropod molluscs." Ethology Ecology & Evolution 2, no. 3 (September 1990): 277–80. http://dx.doi.org/10.1080/08927014.1990.9525412.

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Moffett, Stacia B. "Neural regeneration in gastropod molluscs." Progress in Neurobiology 46, no. 2-3 (June 1995): 289–330. http://dx.doi.org/10.1016/0301-0082(95)80014-y.

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Shepeleva, I. P. "Morphological and optical properties and evolutionary changes of the eye lenses of terrestrial gastropod molluscs (Pulmonata, Stylommatophora)." Ruthenica, Russian Malacological Journal 28, no. 1 (March 2, 2018): 33–38. http://dx.doi.org/10.35885/ruthenica.2018.28(1).5.

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Morphological and optical properties were studied and also evolutionary changes of the eye lenses of some species of terrestrial gastropod pulmonate molluscs were traced. It was demonstrated that all examined properties of the lenses are typical for terrestrial pulmonates. In the course of evolution due to habitat shift by mollusks the lenses were changed only slightly.

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FRÝDA, JIŘÍ, ROBERT B. BLODGETT, ALFRED C. LENZ, and BARBORA FRÝDOVÁ. "Jardamarekia enigma, a new Early Devonian tryblidioidean from Royal Creek area (Yukon Territory, Canada), and paleobiogeography of the Early Devonian of northwestern Canada." Zootaxa 2905, no. 1 (June 3, 2011): 57. http://dx.doi.org/10.11646/zootaxa.2905.1.4.

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The Tryblidia (= Monoplacophora) represents the conchiferan class with the fewest Recent taxa in the phylum Mollusca (Haszprunar 2008) and its phylogeny is still poorly known. This group is known already in Cambrian strata (Early Paleozoic) more than 500 Ma ago. Present-day tryblidian species are known mainly from hadal environments (Schwabe 2008, but see also Wilson et al. 2009) in contrast to Paleozoic species, which have been described only from shallow environments of continental shelves of many paleocontinents (e.g., Horný 1962). A typical feature of fossil as well as living tryblidian species is their rarity. The vast majority of species are known only from several specimens (Haszprunar 2008). Furthermore, description of Paleozoic tryblidian molluscs is strongly underrepresented in the literature, despite the existence of diverse material. This is also true for fossils described in the present study based on a diverse silicified molluscan fauna of mostly gastropods collected from Lower Devonian strata of the Royal Creek area, Yukon Territory (Fig. 1) by Alfred C. Lenz and David G. Perry from 1970–1980. Lists of all hitherto described molluscan species as well as detailed information on their age and locality can be found in Lenz (1977a), Blodgett et al. (2001, 2010) and Frýda et al. (2008). Prior to our studies of the Royal Creek tryblidian and gastropod fauna, no descriptions or illustrations were available for Lower Devonian molluscs of north-western Canada, although a short discussion and faunal lists were provided by Blodgett et al. (1988) for Lower Devonian tryblidians and gastropods from the relatively nearby Delorme Formation of Northwest Territories, and early Emsian (late Early Devonian) tryblidians and gastropods from the Mt. Lloyd George area, northeastern British Columbia. The poor knowledge of Paleozoic tryblidians and gastropods faunas of Laurentia (North America) caused difficulties in the evaluation of Early Devonian paleobiogeography (Blodgett et al. 1999). The present paper is focused on the taxonomy of a new Devonian tryblidian limpet, but it provides also useful data for paleobiogeography and biostratigraphy of the Lower Devonian of western Canada.

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Yang, Chen-Chang, Koh-Chew Han, Tzeng-Jih Lin, Wei-Jen Tsai, and Jou-Fang Deng. "An outbreak of tetrodotoxin poisoning following gastropod mollusc consumption." Human & Experimental Toxicology 14, no. 5 (May 1995): 446–50. http://dx.doi.org/10.1177/096032719501400510.

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Tetrodotoxin, a violent neurotoxin, is present in puffer fish and may occur in a variety of marine animals. Outbreaks of human tetrodotoxin poisoning, following consumption of marine organisms other than puffer fish, has been rare. We here report an outbreak of tetrodotoxin poisoning fol lowing ingestion of gastropod molluscs and its clinical fea tures are discussed. A 71-year-old woman was admitted with hypertension and other neurological symptoms developing after inges tion of some molluscs. A further 16 cases were also found to have typical symptoms of tetrodotoxication after mol lusc consumption. Clinical features in these 17 cases were similar to those conventionally found in tetrodotoxin poisoning, except that there was hypertension in eight cases (47%). All except one case had mild poisoning and recovered well. The molluscs consumed comprised two different species: Nassarius castus and Nassarius conoidalis, both of which were shown to contain various amounts of tetrodotoxin. It is concluded that tetrodotoxin poisoning following mollusc consumption is a possibility. Hypertension, as an unusual feature in tetrodotoxication, is frequent in this outbreak, and should be looked for in future cases. The explanation of hypertension in tetrodotoxication may come either from an exaggerated response to sympathetic stimuli, or due to various responses of the vasomotor centre to a small dose of tetrodotoxin. Further studies are required to answer this question.

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Casoli, Edoardo, Andrea Bonifazi, Giandomenico Ardizzone, Maria Flavia Gravina, Giovanni Fulvio Russo, Roberto Sandulli, and Luigia Donnarumma. "Comparative Analysis of Mollusc Assemblages from Different Hard Bottom Habitats in the Central Tyrrhenian Sea." Diversity 11, no. 5 (May 6, 2019): 74. http://dx.doi.org/10.3390/d11050074.

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Composition, trophic structure, and species-substrate relationships of molluscan assemblages inhabiting different hard bottom habitats (Sabellaria alveolata reef, photophilic bottoms, Phyllophora crispa sciaphilic assemblage, and coralligenous bioconstruction) were studied in two different sites of the Tyrrhenian Sea. In particular, molluscs from the Sabellaria alvevolata (Linnaeus, 1767) reef and coralligenous concretion were investigated, testing the hypothesis that bioconstructions increase the diversity and abundance of associated biota compared to the surrounding habitats. A total of 3134 individuals belonging to the classes of Polyplacophora (5 species, 24 individuals), Bivalvia (39 sp., 2734 ind.), and Gastropoda (53 sp., 376 ind.) were identified. These three taxonomic groups showed different distribution patterns in the studied habitats. Multivariate analyses revealed significant inter-habitat differences in the composition of mollusc assemblages, especially between bioconstructions and the other habitats. S. alveolata and coralligenous host the highest rich molluscan fauna when compared to the neighboring hard bottom habitats characterized by photophilic and sciaphilic assemblages. The first ones were dominated by bivalve suspension feeders, mainly represented by sessile and sedentary organisms, which act as bio-constructors, bio-eroders, or simply inhabit the several microhabitats provided by the bioconstructions, while the second ones host a rich molluscan fauna dominated by gastropod grazers and predators. The present study increases the comparative knowledge of molluscan assemblages inhabiting habitats of littoral plans of the Mediterranean Sea, providing pivotal information regarding biodiversity of coastal zones.

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MARKOVIĆ, VANJA, VUKAŠIN GOJŠINA, BORIS NOVAKOVIĆ, MILENKA BOŽANIĆ, KATARINA STOJANOVIĆ, TAMARA KARAN-ŽNIDARŠIČ, and IVANA ŽIVIĆ. "The freshwater molluscs of Serbia: Annotated checklist with remarks on distribution and protection status." Zootaxa 5003, no. 1 (July 16, 2021): 1–64. http://dx.doi.org/10.11646/zootaxa.5003.1.1.

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We present a checklist of 86 valid freshwater mollusc species of Serbia (65 gastropods and 21 bivalves) belonging to 19 families (15 gastropods and four bivalves). The list is based on our latest research and includes data from published sources and personal communications. The most diverse family among gastropods is Planorbidae (16 species), while Sphaeriidae are most diverse within the bivalves (10 species). Ten species are local endemics (all of them gastropods), while eight are introduced species (three gastropods and five bivalves). The Danube River and its smaller tributaries harbour the most diverse gastropod community, with a total of 61 species (41 gastropods and 20 bivalves). The snail Theodoxus transversalis (Pfeiffer, 1828) and the bivalve Unio crassus Philipson, 1788 are listed as EN (endangered) on the global (IUCN) level, while the snail Plagigeyeria gladilini Kuščer, 1937 and the bivalves Pseudanodonta complanata (Rossmässler, 1835) and Sphaerium rivicola (Lamarck, 1818) are considered as VU (vulnerable) species. Of those IUCN taxa, only U. crassus is listed as protected on the national level (along with 12 mostly local endemic gastropod species). In comparison with the previous checklist of gastropods by Karaman & Karaman (2007), a total of seven species are added here: Belgrandiella serbica Glöer 2008, Bythinella istoka Glöer & Pešić 2014, B. nonveilleri Glöer 2008, B. pesterica Glöer 2008, Acroloxus lacustris (Linnaeus, 1758), Melanoides tuberculata (O.F. Müller, 1774) and Armiger crista (Linnaeus, 1758). In view of global and regional trends in taxonomy, ecology and invasive biology, an even richer diversity of the Serbian freshwater malocofauna can be expected.

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Fera Rahmawati, Yunita, Rizka Apriani Putri, Tatag Bagus Putra Prakarsa, Milade Annisa Muflihaini, and Yoga Putra Aliyani. "Diversity and Distribution of Molluscs in the Intertidal Zone of Nglambor Beach, Gunung Kidul, Yogyakarta." BIO Web of Conferences 33 (2021): 01002. http://dx.doi.org/10.1051/bioconf/20213301002.

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The intertidal zone is the area between the highest and lowest tides, which represents the transition from ocean conditions to land conditions. This study aimed to determine the diversity and distribution of mollusks that exist along the intertidal zone of Nglambor Beach, between August and November 2020. Observations of all molluscs were carried out at two random stations using 10 plots measuring 1 x 1 m 2 with 5 meters. A total of two classes of Mollusca (Gastropod and Bivalvia) belonging to twelve families and 19 species were found from upper to lower an intertidal zone. The upper intertidal zone was recorded to have the highest diversity and an evenness index (Shannon-Wiener diversity index: H ’= 2.524 and Pielou evenness index: J’ = 0.932) compared to the middle and lower zones. It can be concluding that the diversity index in the study location is categorized as medium and its evenness is high. Thais hippocastanum is the most dominant species found in the upper and middle zones, while Thais tissoti dominates in the lower zone. This research contributed to a preliminary checklist on molluscs, which will support a baseline study on the intertidal in future.

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Holovachov, Oleksandr, Sven Boström, Nicole Reid, Anders Warén, and Christoffer Schander. "Endeolophos skeneae sp. nov. (Chromadoridae)—a free-living marine nematode epibiotically associated with deep-sea gastropod Skenea profunda (Skeneidae)." Journal of the Marine Biological Association of the United Kingdom 91, no. 2 (November 11, 2010): 387–94. http://dx.doi.org/10.1017/s0025315410001669.

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A new species, Endeolophus skeneae sp. nov., epibiotically associated with the gastropod Skenea profunda, is described from light microscope and scanning electron microscope observations. The new species is characterized by homogeneous ornamentation of the cuticle with annules with very fine and numerous longitudinal ridges, equally distributed around the body, subcuticular discontinuity in cuticle pattern along the lateral sectors of the body, relatively long body (1.1–1.6 mm) and relatively long tail (141–188 μm, c' = 7.5–11.4), short (19–22 μm) L-shaped spicules with ventrally bent blade and simple plate-like gubernaculum without apophysis. Symbiotic associations between aquatic nematodes and molluscs are discussed, with special emphasis on Dreissena polymorpha, zebra mussels. It is suggested that nematodes find food and shelter in the mantle cavity of the bivalve molluscs, and in the umbilicus and aperture of the gastropods, but to reveal the exact mechanisms of symbiotic associations of nematodes with aquatic molluscs requires further research.

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Hikuroa, Daniel C. H., and Andrzej Kaim. "New gastropods from the Jurassic of Orville Coast, eastern Ellsworth Land, Antarctica." Antarctic Science 19, no. 1 (February 28, 2007): 115–24. http://dx.doi.org/10.1017/s0954102007000168.

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The Latady Group (southern Antarctic Peninsula) hosts the most diverse assemblage of Jurassic molluscs from this continent. A new gastropod mollusc, Silberlingiella latadyensis sp. nov. and three forms assigned to Rissoidae, Pseudomelaniidae and Bullinidae from the Middle-Late Jurassic, Bathonian–Kimmeridgian Hauberg Mountains Formation, Ellsworth Land, Antarctic Peninsula are described here. Silberlingiella is transferred to Eustomatidae and is the first confirmed record of this family in the Southern Hemisphere, indicating a much more widespread Jurassic distribution. The Triassic and Jurassic species of Silberlingiella are compared with the coeval European genus Diatinostoma. Eustomatidae is proposed as an ancestral group for Potamididae and Batillariidae. The composition of the gastropod association described herein differs markedly from the only other Antarctic Jurassic fauna from Alexander Island.

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Cunha, Tauana Junqueira, and Gonzalo Giribet. "A congruent topology for deep gastropod relationships." Proceedings of the Royal Society B: Biological Sciences 286, no. 1898 (March 13, 2019): 20182776. http://dx.doi.org/10.1098/rspb.2018.2776.

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Gastropod molluscs are among the most diverse and abundant animals in the oceans, and are successful colonizers of terrestrial and freshwater environments. Past phylogenetic efforts to resolve gastropod relationships resulted in a range of conflicting hypotheses. Here, we use phylogenomics to address deep relationships between the five major gastropod lineages—Caenogastropoda, Heterobranchia, Neritimorpha, Patellogastropoda and Vetigastropoda—and provide one congruent and well-supported topology. We substantially expand taxon sampling for outgroups and for previously underrepresented gastropod lineages, presenting new transcriptomes for neritimorphs and patellogastropods. We conduct analyses under maximum-likelihood, Bayesian inference and a coalescent-based approach, accounting for the most pervasive sources of systematic errors in large datasets: compositional heterogeneity, site heterogeneity, heterotachy, variation in evolutionary rates among genes, matrix completeness, outgroup choice and gene tree conflict. We find that vetigastropods and patellogastropods are sister taxa, and that neritimorphs are the sister group to caenogastropods and heterobranchs. We name these two major unranked clades Psilogastropoda and Angiogastropoda, respectively. We additionally provide the first genomic-scale data for internal relationships of neritimorphs and patellogastropods. Our results highlight the need for reinterpreting the evolution of morphological and developmental characters in gastropods, especially for inferring their ancestral states.

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Wollesen, Tim, Sonia Victoria Rodríguez Monje, André Luiz de Oliveira, and Andreas Wanninger. "Staggered Hox expression is more widespread among molluscs than previously appreciated." Proceedings of the Royal Society B: Biological Sciences 285, no. 1888 (October 10, 2018): 20181513. http://dx.doi.org/10.1098/rspb.2018.1513.

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Hox genes are expressed along the anterior–posterior body axis in a colinear fashion in the majority of bilaterians. Contrary to polyplacophorans, a group of aculiferan molluscs with conserved ancestral molluscan features, gastropods and cephalopods deviate from this pattern by expressing Hox genes in distinct morphological structures and not in a staggered fashion. Among conchiferans, scaphopods exhibit many similarities with gastropods, cephalopods and bivalves, however, the molecular developmental underpinnings of these similar traits remain unknown. We investigated Hox gene expression in developmental stages of the scaphopod Antalis entalis to elucidate whether these genes are involved in patterning morphological traits shared by their kin conchiferans. Scaphopod Hox genes are predominantly expressed in the foot and mantle but also in the central nervous system. Surprisingly, the scaphopod mid-stage trochophore exhibits a near-to staggered expression of all nine Hox genes identified. Temporal colinearity was not found and early-stage and late-stage trochophores, as well as postmetamorphic individuals, do not show any apparent traces of staggered expression. In these stages, Hox genes are expressed in distinct morphological structures such as the cerebral and pedal ganglia and in the shell field of early-stage trochophores. Interestingly, a re-evaluation of previously published data on early-stage cephalopod embryos and of the gastropod pre-torsional veliger shows that these developmental stages exhibit traces of staggered Hox expression. Considering our results and all gene expression and genomic data available for molluscs as well as other bilaterians, we suggest a last common molluscan ancestor with colinear Hox expression in predominantly ectodermal tissues along the anterior–posterior axis. Subsequently, certain Hox genes have been co-opted into the patterning process of distinct structures (apical organ or prototroch) in conchiferans.

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Page, Louise R. "Developmental modularity and phenotypic novelty within a biphasic life cycle: morphogenesis of a cone snail venom gland." Proceedings of the Royal Society B: Biological Sciences 279, no. 1726 (May 18, 2011): 77–83. http://dx.doi.org/10.1098/rspb.2011.0501.

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The venom gland of predatory cone snails ( Conus spp.), which secretes neurotoxic peptides that rapidly immobilize prey, is a proposed key innovation for facilitating the extraordinary feeding behaviour of these gastropod molluscs. Nevertheless, the unusual morphology of this gland has generated controversy about its evolutionary origin and possible homologues in other gastropods. I cultured feeding larvae of Conus lividus and cut serial histological sections through the developing foregut during larval and metamorphic stages to examine the development of the venom gland. Results support the hypothesis of homology between the venom gland and the mid-oesophageal gland of other gastropods. They also suggest that the mid-region of the gastropod foregut, like the anterior region, is divisible into dorsal and ventral developmental modules that have different morphological, functional and ontogenetic fates. In larvae of C. lividus , the ventral module of the middle foregut transformed into the anatomically novel venom gland of the post-metamorphic stage by rapidly pinching-off from the main dorsal channel of the mid-oesophagus, an epithelial remodelling process that may be similar to other cases where epithelial tubes and vesicles arise from a pre-existing epithelial sheet. The developmental remodelling mechanism could have facilitated an abrupt evolutionary transition to the derived morphology of this important gastropod feeding innovation.

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Schluessel, V., M. B. Bennett, and S. P. Collin. "Diet and reproduction in the white-spotted eagle ray Aetobatus narinari from Queensland, Australia and the Penghu Islands, Taiwan." Marine and Freshwater Research 61, no. 11 (2010): 1278. http://dx.doi.org/10.1071/mf09261.

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Aetobatus narinari, a circumglobal batoid, is subjected to increasing fishing pressures, especially throughout South-east Asia. However, its management and protection is complicated by the lack of relevant life history information. It appears to be a late-maturing, long-lived stingray with a size-at-maturity of ∼130 and >150 cm in ventral disc width for males and females respectively. Like other myliobatids, A. narinari is a matrotrophic viviparous species exhibiting lipid histotrophy as indicated by trophonemata. Only the left ovary and uterus are functional. The presence of mature sperm in the testes, collecting ducts, epididymis and ductus deferens coincided with the estimated time of parturition and mating. Catches indicated an unbiased sex ratio. Aetobatus narinari is a hard-prey specialist that feeds mainly on gastropods, molluscs and hermit crabs (Diogenidae). Molluscs comprised numerically and gravimetrically the most important prey group (Index of Relative Importance (IRI): 85.9% in Australia, 99.9% in Taiwan) and were observed in 83.3% and 100% of stomachs containing food from Australia and Taiwan respectively. Minor dietary shifts from a gastropod–crustacean to a more gastropod–bivalve based diet occurred as body size increased. This study provides vital biological data for the effective management and conservation of A. narinari.

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THIRIOT-QUIÉVREUX, CATHERINE. "ADVANCES IN CHROMOSOMAL STUDIES OF GASTROPOD MOLLUSCS." Journal of Molluscan Studies 69, no. 3 (August 2003): 187–202. http://dx.doi.org/10.1093/mollus/69.3.187.

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Miller, Mark W. "GABA as a Neurotransmitter in Gastropod Molluscs." Biological Bulletin 236, no. 2 (April 2019): 144–56. http://dx.doi.org/10.1086/701377.

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32

Suboski, Milton D. "Releaser-induced recognition learning by gastropod molluscs." Behavioural Processes 27, no. 1 (January 1992): 1–26. http://dx.doi.org/10.1016/0376-6357(92)90036-d.

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Désy, JC, J. F. Archambault, B. Pinel-Alloul, J. Hubert, and P. GC Campbell. "Relationships between total mercury in sediments and methyl mercury in the freshwater gastropod prosobranch Bithynia tentaculata in the St. Lawrence River, Quebec." Canadian Journal of Fisheries and Aquatic Sciences 57, S1 (March 14, 2000): 164–73. http://dx.doi.org/10.1139/f99-231.

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Total Hg concentrations in sediment and methyl mercury (MeHg) levels in the gastropod species Bithynia tentaculata were evaluated at 21 stations in the fluvial corridor of the St. Lawrence River (Quebec, Canada). In the sediments (n = 21), total Hg concentrations ranged from 34 to 2790 ng·g dry weight-1. In the gastropods, MeHg concentrations varied from 15 to 290 ng·g dry weight-1 in undepurated gastropods (n = 20) and from 41 to 420 ng·g dry weight-1 in depurated gastropods (n = 13; without gut contents). The southern sector of Lake St. Louis, located near the Îles-de-la-Paix, had significantly higher Hg concentrations than any other sectors under study, both for total Hg in the sediments and MeHg in the gastropods. We established linear models to describe the relationships between Hg contamination in sediments and molluscs for the fluvial corridor of the St. Lawrence River and for the Lake St. Louis sector. Total Hg in sediments and MeHg in gastropods were highly correlated for all pooled stations (r = 0.83), and the relationship was even stronger for the Lake St. Louis stations (r = 0.92). Our study suggests that the gastropod B. tentaculata is a promising biomonitor species for assessing Hg contamination in the fluvial corridor and lakes of the St. Lawrence River.

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Gregory, T. Ryan. "Genome size estimates for two important freshwater molluscs, the zebra mussel (Dreissena polymorpha) and the schistosomiasis vector snail (Biomphalaria glabrata)." Genome 46, no. 5 (October 1, 2003): 841–44. http://dx.doi.org/10.1139/g03-069.

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The haploid genome sizes of two important molluscs were assessed by Feulgen image analysis densitometry. The genome size of the zebra mussel (Dreissena polymorpha), a prolific invader of North American lakes, was estimated to be 1C = 1.70 ± 0.03 pg, and that of the freshwater snail Biomphalaria glabrata, the predominant intermediate vector of the human parasite Schistosoma mansoni, was estimated at 0.95 ± 0.01 pg. These estimates will be important in future efforts in molluscan genomics, which at present lags far behind work being carried out with vertebrate and arthropod models. B. glabrata in particular, which has one of the smallest known gastropod genomes, is recommended as a highly suitable target for future genome sequencing.Key words: densitometry, DNA content, DNA sequencing, Feulgen, image analysis, Great Lakes, invading species, molluscs, Schistosoma mansoni.

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35

Shepeleva, I. P. "Morphological and optical properties and evolutionary changes of tentacular epidermis and cornea of the eyes of terrestrial gastropod molluscs (Pulmonata, Stylommatophora)." Ruthenica, Russian Malacological Journal 28, no. 4 (October 26, 2018): 151–56. http://dx.doi.org/10.35885/ruthenica.2018.28(4).3.

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Morphological and optical properties of tentacular epidermis and cornea of the eyes of some species of terrestrial gastropod pulmonate molluscs were studied and their evolutionary transformations were estimated. It was demonstrated that all examined properties of tentacular epidermis and cornea of these species are typical for terrestrial pulmonates. In the course of evolution tentacular epidermis of terrestrial pulmonate molluscs was modified to less extent than cornea, and both these structures underwent minor changes in comparison with analogous structures of the eyes of marine prosobranch molluscs.

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36

Fortey, R. A., and ]. S. Peel. "Early Ordovician trilobites and molluscs from the Poulsen Cliff Formation, Washington Land, western North Greenland." Bulletin of the Geological Society of Denmark 38 (April 25, 1990): 11–32. http://dx.doi.org/10.37570/bgsd-1990-38-02.

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A well-preserved, shallow water bathyurid trilobite fauna of early Ordovician age, and associated gastropods and an undetermined hyolith are described from the Poulsen Cliff Formation of Washington Land, western North Greenland. Two new bathyurid species, Licnocephala sminue and Pe/tabellia elegans, and a new gastropod species, Plethospira(?) floweri, are described. Biolgina Maximova is considered a junior subjective synonym of Peltabellia Whittington. The distribution of the genus is an example of close relationship between shallow water trilobite faunas of Laurentia and the North-east Siberian platform in the early Ordovician.

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Mumladze, L., A. Bikashvili, B. Japoshvili, and V. V. Anistratenko. "New Alien Species Mytilopsis Leucophaeata and Corbicula Fluminalis (Mollusca, Bivalvia) Recorded in Georgia and Notes on Other Non-Indigenous Molluscs Invaded the South Caucasus." Vestnik Zoologii 53, no. 3 (June 1, 2019): 187–94. http://dx.doi.org/10.2478/vzoo-2019-0019.

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Abstract First records of invasive bivalve freshwater mollusc species Mytilopsis leucophaeata (Conrad, 1831) and Corbicula fluminalis (O. F. Müller, 1774) in Georgia are reported. No native or alien extant dreissenid species have ever been recorded form this region so far. A finding of C. fluminalis in Georgia is also a new record for the country though this species inhabits the rivers of adjacent Azerbaijan. Apart from two mentioned bivalve molluscs three non-indigenous gastropod species are registered from Georgia: freshwater Ferrisia californica (Rowell, 1863) and Physella acuta (Draparnaud, 1805) and land snail Eobania vermiculata (O. F. Müller, 1774).

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Wright, William G. "Behavior and its Neural Control in Gastropod Molluscs." Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology 136, no. 3 (November 2003): 791–92. http://dx.doi.org/10.1016/s1095-6433(03)00217-4.

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Willows, A. O. D. "Behavior and Its Neural Control in Gastropod Molluscs." Integrative and Comparative Biology 43, no. 1 (February 1, 2003): 238. http://dx.doi.org/10.1093/icb/43.1.238.

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Emery, Dennis G. "Fine structure of olfactory epithelia of gastropod molluscs." Microscopy Research and Technique 22, no. 4 (September 1, 1992): 307–24. http://dx.doi.org/10.1002/jemt.1070220402.

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Lindberg, David R., and Robert P. Guralnick. "Phyletic patterns of early development in gastropod molluscs." Evolution and Development 5, no. 5 (September 2003): 494–507. http://dx.doi.org/10.1046/j.1525-142x.2003.03055.x.

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Kerr-Lawson, L. J., P. F. Karrow, T. W. D. Edwards, and G. L. Mackie. "A paleoenvironmental study of the molluscs from the Don Formation (Sangamonian?) Don Valley Brickyard, Toronto, Ontario." Canadian Journal of Earth Sciences 29, no. 11 (November 1, 1992): 2406–17. http://dx.doi.org/10.1139/e92-188.

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The Don Formation comprises 8–9 m of fossiliferous stratified sand and clay, lying between glacial deposits of Wisconsinan and presumed Illinioan age. It has yielded a diverse fossil flora and fauna indicating a climate as warm as or warmer than present and is considered to be of last, or Sangamonian, interglacial age. About 2 t of sediment were processed from the type section of the Don Formation at Toronto, Ontario, and yielded approximately 18 000 identifiable mollusc shells, representing 45 taxa. Previously unpublished taxa include 11 freshwater gastropod species, 12 pelecypod species (Sphaeriidae), and 7 terrestrial gastropod species. The molluscs are mainly concentrated in the lower two-thirds of the formation and are dominated by Valvata perdepressa, with abundant Valvata sincera, Probythinella lacustris, Amnicola limosa, Amnicola walkeri, Pleurocera acuta, Elimia livescens, Pisidium casertanum, Pisidium compressum, Pisidium fallax, and Sphaerium striatinum. All the mollusc species are modern inhabitants of the Great Lakes region. Their known ecological tolerances suggest deposition in relatively shallow waters of a large temperate lake having substantial fluvial input nearby. Stratigraphic variations in the relative abundance of different aquatic taxa may reflect variations in water depth or fluvial activity. Stable isotope data from several mollusc species and a single wood specimen, together with taxonomic paleoenvironmental interpretation, are consistent with deposition during the climatic optimum of the Sangamonian interglaciation. Environmental conditions and faunas are similar to those of the Nipissing phase (Hypsithermal) of the eastern Great Lakes.

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OZTURK, B. "A new alien gastropod Pseudorhaphitoma iodolabiata (Hornung & Mermod, 1928) (Mangeliidae, Mollusca) in the Mediterranean Sea." Mediterranean Marine Science 13, no. 1 (January 9, 2012): 30. http://dx.doi.org/10.12681/mms.20.

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The study documents the occurrence of a new alien gastropod Pseudorhaphitoma iodolabiata in the Mediterranean Sea, collected inIskenderun Bay, Turkey, on September 2011. This record increases to 213 the number of alien molluscs in the Mediterranean.

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Munt, Martin C. "Mollusca from the Insect Limestone (Bembridge Marls Member: Bouldnor Formation: Solent Group), Palaeogene, Isle of Wight, southern England." Earth and Environmental Science Transactions of the Royal Society of Edinburgh 104, no. 3-4 (September 2013): 263–74. http://dx.doi.org/10.1017/s1755691014000048.

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ABSTRACTMolluscs from the Insect Limestone of the Bembridge Marls Member are described. The gastropods Lymnaea (Galba) longiscata (Brongniart 1810), Planorbarius discus (Edwards 1852), Gyraulus similis Férussac, 1814, Hippeutis headonensis Jodot, 1942, Viviparus lentus (Solander 1766) and Viviparus angulosus (J. Sowerby 1817) indicate freshwater alkaline conditions. The cerithioid gastropod Tarebia acuta (J. Sowerby 1822) probably represent more brackish conditions. Polymesoda (Pseudocyrena) obovata (J. Sowerby 1817) is the only bivalve present. All were potentially washed into the depocentre. Despite a wide outcrop of the Insect Limestone on the Isle of Wight's northwest and northeast coasts, there are no records of molluscs other than from the Gurnard/Thorness Bay area on the northwest coast of the island.

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Shepeleva, I. P. "Cellular composition, morphological characteristic and evolutionary changes of photoreceptor apparatus of the camera eyes of terrestrial gastropod molluscs (Heterobranchia, Stylommatophora)." Ruthenica, Russian Malacological Journal 30, no. 2 (April 5, 2020): 93–101. http://dx.doi.org/10.35885/ruthenica.2021.30(2).3.

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Cellular composition and morphology of components of photoreceptor apparatus of the retinae of camera eyes of some species of terrestrial gastropod pulmonate molluscs were studied and its evolutionary transformations were traced. It was demonstrated that all examined characteristics of photoreceptor apparatus of the most investigated species were normal for terrestrial pulmonates, while those of one species were special. Evolutionary transformations of photoreceptor apparatus of terrestrial pulmonate molluscs due to habitat shift were quite significant and concerned of its cellular composition and morphology of photoreceptor cells.

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Albrecht, C., H. Vogel, T. Hauffe, and T. Wilke. "Sediment core fossils in ancient Lake Ohrid: testing for faunal change in molluscs since the Last Interglacial period." Biogeosciences Discussions 7, no. 3 (May 28, 2010): 3969–99. http://dx.doi.org/10.5194/bgd-7-3969-2010.

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Abstract. Ancient Lake Ohrid is probably of early Pleistocene or Pliocene origin and amongst the few lakes in the world harboring an outstanding degree of endemic biodiversity. Although there is a long history of evolutionary research in Lake Ohrid, particularly on molluscs, a mollusc fossil record has been missing up to date. For the first time, gastropod and bivalve fossils are reported from the basal, calcareous part of a 2.6 m long sediment succession (core Co1200) from the north-eastern part of Lake Ohrid. Electron spin resonance (ESR) dating of mollusc shells from the same stratigraphic level yielded an age of 130±28 ka. Lithofacies III sediments, i.e. a subdivision of the stratigraphic unit comprising the basal succession of core Co1200 between 181.5–263 cm appeared solid, grayish-white, and consisted almost entirely of silt-sized endogenic calcite (CaCO3>70%) and intact and broken mollusc shells. Here we compare the faunal composition of the thanatocoenosis with recent mollusc associations in Lake Ohrid. A total of 13 mollusc species (9 gastropod and 4 bivalve species) could be identified within Lithofacies III sediments. The value of sediment core fossils for reconstructing palaeoenvironmental settings was evaluated. The agreement between sediment and palaeontological proxies was tested. The combined findings of the ecological study and the sediment characteristics suggest deposition in a shallow water environment during the Last Interglacial period. We tested for major faunal changes since the Last Interglacial period and searched for signs of extinction events. The fossil fauna exclusively included species also found in the present fauna, i.e. no extinction events are evident for this site since the Last Interglacial. The thanatocoenosis showed the highest similarity with recent Intermediate Layer (5–25 m) mollusc assemblages. The demonstrated existence of a mollusc fossil record in Lake Ohrid sediment cores also has great significance for future deep drilling projects. It can be hoped that a more far reaching mollusc fossil record will then be obtained, enabling insight into the early evolutionary history of Lake Ohrid.

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LLOYD, PHILIP E. "Peripheral Actions of the SCPs inAplysiaand Other Gastropod Molluscs." American Zoologist 29, no. 4 (November 1989): 1265–74. http://dx.doi.org/10.1093/icb/29.4.1265.

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Dzik, Jerzy, and Dawid Mazurek. "Affinities of the alleged earliest Cambrian gastropod Aldanella." Canadian Journal of Zoology 91, no. 12 (December 2013): 914–23. http://dx.doi.org/10.1139/cjz-2013-0119.

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Unlike true Palaeozoic gastropods, but similar to some coeval hyoliths, the cup-like hemispherical embryonic shell of Aldanella attleborensis (Shaler and Foerste, 1888) from the earliest Cambrian (early Tommotian) Erkeket Formation of northern Siberia bears a mucro. Also, the pattern of mortality, with right-skewed distribution and a peak at about 1.0 mm diameter, is not similar to that of early Palaeozoic gastropods; there is no evidence of metamorphosis that would end the pelagic larval stage of ontogeny. Specimens of larger size are rare in samples of phosphatized “small shelly fossils” but are known in related species of the genus, of up to 3–5 mm diameter. A phosphatized soft body is preserved in a few specimens of A. attleborensis, one bearing possible chaetae of about 5 μm diameter. Such bunches of chaetae arming locomotory organs were earlier identified in the genus Pelagiella Matthew, 1895, a more derived member of the same lineage. It shares with the genus Aldanella Vostokova, 1962 also the mucronate embryonic shell and acicular aragonitic shell wall microstructure. The presence of chaetae-bearing organs suggests pelagic mode of life of pelagiellids at maturity. Middle Cambrian Pelagiella shells reached 7 mm in diameter, suggesting evolutionary increase in mature size. Embryonic shell morphology, wall microstructure, and the presence of locomotory organs with a fan of chaetae contradicts gastropod, and even conchiferan affinity of the pelagiellids, but together with the pattern of ontogeny conforms to the enigmatic Palaeozoic hyoliths. They differ in having opercula closing the shell apertures and in lacking evidence of chaetae. The helens, paired apertural appendages of possible locomotory function occurring in apertures of some of them, do not reveal any similarity to chaetae in their development. We propose classifying the order Pelagiellida in the class Hyolitha rather than in the class Gastropoda, until its phylogenetic position is clarified. Such understood hyoliths may represent the earliest stage in evolution of molluscs, immediately following initial diversification of the spiralians (lophotrochozoans) into phyla.

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Cleveland, G., and G. C. Kearn. "The function of the paraoesophageal glands in an echinostome (digenean) cercaria (? Cercaria spinifera La Valette, 1855)." Journal of Helminthology 63, no. 3 (September 1989): 231–38. http://dx.doi.org/10.1017/s0022149x00009032.

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ABSTRACTAn echinostome cercaria (? Cercaria spinifera La Valette, 1855) with 37 collar spines and paraoesophageal glands has been recorded for the first time in Britain from the gastropod Planorbarius corneus. The cercariae penetrate into and encyst in planarians. Observations made on cercariae during penetration indicate that the paraoesophageal glands are used to enter the body of the planarian and that the so-called penetration glands have some other function. Gastropod molluscs may also serve as second intermediate hosts, but there is evidence to indicate that anatomically similar cercariae from different host individuals vary in their second intermediate host preferences.

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Perkins, E. J. "The Biological Accumulation and Monitoring of Chemical Wastes in Arctic Waters." Water Science and Technology 18, no. 2 (February 1, 1986): 1–11. http://dx.doi.org/10.2166/wst.1986.0011.

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The biological accumulation and monitoring of chemical wastes are considered with particular reference to the Solway Firth, U.K. Monitoring of the influence of chemical wastes may be concerned with somatic or reproductive responses and is more usually the former. It is shown that size and abundance are not an indication of a species fertility which is crucial to its conservation. Diet has an important influence upon the magnitude of the trace element burden of gastropod molluscs and it is shown that the fertility of Patella vulgata and Littorina littorea is unaffected by marked increases in the trace element burden. In this study, some of the species examined viz., the polychaete worms Phyllodoce maculata and Scoloplos armiger, the decapod crustacean Pagurus bernhardus and the gastropod molluscs, Littorina littorea and Thais lapillus, have a distribution which extends into arctic waters. Clearly such animals offer the opportunity for comparative studies to test the more general application of the work reported. Such comparative work would also facilitate efforts to apply data from the boreal region to problems in the Arctic.

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Journal articles on the topic 'Gastropod molluscs'

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