Mollusca

Despite their perceived inaccessibility, the marine intertidal and benthic environments of Antarctica, southern Africa and South America have continued to provide marine natural products for chemists with unique opportunities to study the secondary metabolite constituents and chemical ecology of a diverse array of marine gastropod molluscs. This review covers the literature up to 31 January 2005 and describes the structures and, where applicable, biological activities of 100 secondary metabolites isolated from 21 species of marine gastropod molluscs. Not unexpectedly, the chemistry of chemically defended shell-less opisthobranchs dominates the natural product studies of molluscs collected from these regions of the southern hemisphere.

In this study, in order to analyze Mollusca species and determining their relationship with the sediment factors, sediment samples were gathered during spring, summer, autumn and winter 2012 from 12 stations (ranging in depths 5, 10, 20 and 50 meters) in the Southern Caspian Sea from Behshahr to Ramsar (Mazandaran, Iran). The sediment factors (grain size, total organic matter and calcium carbonate concentration) were measured in laboratory. Two classes of Mollusca (Bivalvia and Gastropoda) were identified. Class Bivalvia had 3 species (Didacna protracta, Hypanis caspia, Abra ovata) which belong to 3 genera of 2 families and class Gastropoda had 4 species (Pergola sp., Anisus kolesnikovi, Abeskunus sphaerion, Ulskia ulskii) which belong to 4 genera of 3 families. Most dominant species of Bivalvia was Abra ovata (46.2 individuals/0.1m 2) and that of Gastropoda was Abeskunus sphaerion (58.66 individuals/0.1m 2). The mean of maximum and minimum density of Mollusca was observed in spring (29.67 individuals/0.1m 2) and winter (0 individuals/0.1m 2) respectively. The results of One Way ANOVA showed that density of Mollusca was different significantly with depth and season (P<0.05). Results of Pearson correlation showed that between density of Mollusca and salinity, %silt and clay, TOM and depth had been negative positive correlation and had been positive correlation with temperature.

A simple and sensitive in situ method for monitoring the occurrence of toxic algal blooms and shellfish contamination events has been developed. The technique involves the passive adsorption of biotoxins onto porous synthetic resin filled sachets (SPATT bags) and their subsequent extraction and analysis. The success of the method is founded on the observation that during algal blooms significant amounts of toxin, including the low polarity lipophilic compounds such as the pectenotoxins and the okadaic acid complex toxins, are dissolved in the seawater. The results of field trials during Dinophysis acuminata and Protoceratium reticulatum blooms are presented. These data prove the concept and demonstrate that the technique provides a means of forecasting shellfish contamination events and predicting the net accumulation of polyether toxins by mussels. As an early warning method it has many advantages over current monitoring techniques such as shellfish-flesh testing and phytoplankton ...

The old castle hill in Spangenberg has a rich mollusk fauna that was first described by DIEMAR in 1881. In 2019 followed a new survey on land snails that was carried out by members of the hessian working group on molluscs. Diemar has reportet 15 species, additional 5 were detected in the collection of the Senckenberg Research Institute and Natural History Museum. In the actual survey 33 different species could be collected. Zusammenfassung Nach der Publikation von DIEMAR (1881) erfolgte in 2019 eine neue Erhebung zu den Landschnecken des Schlossberges Spangenberg. In 1881 konnten 15 Arten gefunden werden, 5 weitere konnten in den Sammlungen des Senckenberg Forschungsinstitutes und Naturmuseum gefunden werden. Bei der aktuellen Untersuchung ergaben sich 33 Arten.

The studies primary objective was to establish whether there was a difference in ciliary activity upon immersion in the aqueous smoke extracts from filtered and non-filtered cigarettes. The result was that there was indeed a difference in ciliary activity. The cilia’s BPM reduction was much more substantial within the specimen when immersed in aqueous extracts from a non-filtered cigarette than in comparison with the control of seawater as well as aqueous smoke extracts from the filtered cigarette. The BPM of the cilia immersed within the seawater was greater than that of the specimen immersed within the non-filtered cigarette aqueous extracts, however it is to no degree as detrimental as the non-filtered extract. This observation deduces the principle idea that smoking a cigarette without a filter has much more of a substantial effect on the ciliary activity, and likewise that there are similar, yet less substantial impediments of ciliary activity within the process of smoking cigarettes with filters opposed to not smoking at all. In over all aspects of the study, the results were very consistent with the predictions and proposed hypothesis of impeded ciliary activity which allow it remain highly complimentary in regards to studies conducted with similar parameters and goals such as those highlighted throughout this paper.

Resumo: O Livro Didático (LD) é um dos principais recursos utilizados pelos professores, podendo ser importante na aprendizagem de Ciências, e por possuírem limitações, é relevante a sua análise crítica referente aos conteúdos propostos nestes. Esse trabalho teve como objetivo geral analisar os conteúdos conceituais e a importância do filo Mollusca nos LD de Ciências (6º ao 9º ano) publicados e aprovados pelo PNLD no período de 2010 a 2016. A abordagem da pesquisa foi de cunho qualitativo, utilizou-se o método da Pesquisa Bibliográfica e da técnica de Análise de Conteúdo do tipo categorial. Analisou-se as seguintes categorias: importância médica, alimentar, econômica e ecológica; morfologia externa (concha e massa visceral); Sistemas anatômicos e fisiológicos; classificação, sistemática e taxonomia. Das 154 obras analisadas, 89 não apresentavam a temática em questão. Geralmente o conteúdo sobre moluscos era abordado no capítulo específico sobre o filo (livros do 7º ano) ou em tópicos relacionados a parasitoses humanas, meio ambiente e aspectos sobre Geologia/Paleontologia. Foram observados reduzido conteúdo conceitual, erros quanto á escrita de nomes científicos das espécies e generalizações errôneas sobre os moluscos. Das 8 classes de moluscos existentes, todos os LD descreviam apenas sobre os bivalves, gastrópodes e cefalópodes. Aspectos positivos foram evidenciados, tais como, sugestões metodológicas, cladogramas, leituras complementares e exemplos de organismos desse filo importantes tanto do ponto vista da alimentação humana quanto dos aspectos culturais. Podemos concluir que o LD não deve ser o único recurso didático utilizado pelo professor de Ciências em sala de aula, uma vez que este é insuficiente com relação aos conteúdos conceituais sobre os moluscos.

Abstract: The Textbook (LD) is one of the main resources used by professors and may be useful in science learning. Because of their limitations, it is necessary a critical analysis regarding the contents proposed on them. This article had as general objective to analyze the conceptual contents and the importance of the phylum Mollusca in the Science LD (6th to 9th grade) published and approved by PNLD from 2010 to 2016. The research approach was of a qualitative nature. The Bibliographic Research method and the categorical content analysis technique were used. The following categories were analyzed: medical, food, economic and ecological importance; external morphology (shell and visceral mass); Anatomical and physiological systems; classification, systematics and taxonomy. Of the 154 works analyzed, 89 did not present the theme in question. Generally, mollusk content was covered in the phylum-specific chapter (7th grade books) or in topics related to human parasitosis, environment, and aspects of geology / paleontology. Reduced conceptual content, errors about writing scientific names of species and erroneous generalizations about mollusks were observed. Of the 8 existing classes of mollusks, all LD described only about bivalves, gastropods and cephalopods. Positive aspects were also evidenced, such as methodological suggestions, cladograms, complementary readings and examples of organisms from this phylum as human food importance as well as cultural aspects. In conclusion, it is possible to affirm that LD must not be the unique didactic resource used by science teacher in classroom, since it is insufficient about the molluscs conceptual contents.

The fern genus Dryopteris (Dryopteridaceae) is represented in the Hawaiian Islands by 18 endemic taxa and one non-endemic, native species. The goals of this study were to determine whether Dryopteris in Hawai’i is monophyletic and to infer the biogeographical origins of Hawaiian Dryopteris by determining the geographical distributions of their closest living relatives. We sequenced two chloroplast DNA fragments, rbcL and the trnL-F intergenic spacer (IGS), for 18 Hawaiian taxa, 45 non-Hawaiian taxa, and two outgroup species. For individual fragments, we estimated phylogenetic relationships using Bayesian inference and maximum parsimony. We performed a combined analysis of both cpDNA fragments employing Bayesian inference, maximum parsimony, and maximum likelihood. These analyses indicate that Hawaiian Dryopteris is not monophyletic, and that there were at least five separate colonizations of the Hawaiian Islands by different species of dryopteroid ferns, with most of the five groups having closest relatives in SE Asia. The results suggest that one colonizing ancestor, perhaps from SE Asia, gave rise to eight endemic taxa (the glabra group). Another colonizing ancestor, also possibly from SE Asia, gave rise to a group of five endemic taxa (the exindusiate group). Dryopteris fusco-atra and its two varieties, which are endemic to Hawai’i, most likely diversified from a SE Asian ancestor. The Hawaiian endemic Nothoperanema rubiginosum has its closest relatives in SE Asia, and while the remaining two species, D. wallichiana and D. subbipinnata, are sister species, their biogeographical origins could not be determined from these analyses due to the widespread distributions of D. wallichiana and its closest non-Hawaiian relative.

The influence of Quarternary glacial cycles on the extant diversity of Holarctic species has been intensively studied. It has been hypothesized that palaeoclimatic changes are responsible for divergence events in lineages. A constant improvement in DNA sequencing and modeling methods, as well as palaeoclimatic reconstruction, permit a deeper exploration of general causes of speciation in geological time. In the present study, we sampled, as exhaustively as possible, the butterflies belonging to the genus Melitaea (Lepidoptera: Nymphalidae), which are widely spread in the Palaearctic region. We conducted analyses to assess the phylogeny of the genus and estimated the timing of divergence and the most likely distribution of ancestral populations. The results obtained indicate that the systematics of the genus is in need of revision and that the diversity of the genus has been profoundly shaped by palaeoenvironmental changes during its evolutionary history. The present study also emphasizes that, when employed with caveats, major palaeoenvironmental events could represent very powerful tools for the calibration of the dating of divergences using molecular data. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 97, 346–361.

The gastropod family Xenophoridae affix foreign objects to the shell surface. The objects include bivalve shells, smaller gastropod shells, shell fragments and encrusting corals. We identified gastropods attached on 100 shells of Xenophora pallidula (Reeve, 1842). We found that the buccinid Nassaria nivea (Gmelin, 1791), Bursa sp., the turrid Turricula javana (Linne, 1758) and the nassarid Bullia vittata (Linne, 1758) were the most common objects. Fragments and bivalve shells could not be identified.

In this study, a new evidence of Neogastropods of the family Costellariidae MacDonald, 1860 from the Miocene of Central Paratethys is presented. The finds of fossil shells of the genus Vexillum Röding, 1798 derives from the middle Miocene (Serravallian) marine deposits from the eastern margin of the Vienna Basin (Western Carpathians, Slovakia), which belongs to the north-west Central Paratethys realm. The studied gastropods were discovered at the locality Rohožník – Konopiská, in the basinal pelitic facies and organodetritic corallinacean marls of the Studienka Formation of late Badenian age (Bulimina-Bolivina Biozone). The material studied here includes two new species: Vexillum svagrovskyi sp. nov. and Vexillum pseudoschafferi sp. nov. The affinity and comparison of both species with other similar costellariids from the Neogene of European Eastern Atlantic, Proto-Mediterranean and Paratethyan regions are discussed. From a paleoecological point of view, the results suggest that V. svagrovskyi was adapted to a moderately deep, circalittoral environment with occasional worsening of the paleoecological conditions (low bottom water oxygenation), whereas species V. pseudoschafferi preferred a shallow-water infralittoral environment.

Xenophora (Xenophora) crispa (konig, 1825) (Gastropoda: Xenophoridae) is a marine mollusc with a shell of medium size and with wide geographical and bathymetric distribution. In this work are provided biometric unpublished data on this species that is compared with X. (X.) senegalensis P. Fischer, 1873, the species more similar morphologically.

The Mediterranean coast of Israel can be divided into two distinct provinces (south to north): the Nilotic, which up to the construction of the Aswan Dam received most of its quartz-rich sediments from the Nile, and the Levantine, which receives most of its sediments from local, carbonate-rich sources. These differences in sediment composition should have a strong effect on the faunal composition. We studied the very abundant molluscan fauna, a major biogenic component of the shallow Mediterranean sediments and suggest that variations in assemblages are associated with different substrates. We examined the dead molluscan component of sediment samples collected at 40 m water depth at five stations along the Israeli Mediterranean coast to determine the variations in biodiversity trends. The use of shelly death assemblages that accumulate on the seafloor averages out short-term, environmental fluctuations such as seasonality and reproduction, and presents a more complete " modern " picture than would be attained based on single live censuses alone. More than 2000 specimens yielded 114 species, with the bivalve Corbula gibba being the most abundant. Samples originating from the Levantine Province show greater species richness and a higher portion of epifaunal species compared to samples from the Nilotic Province. Specifically, 30 bivalves and 20 gastropods were only found in the Levantine samples, while only six bivalves and three gastropods were only found in the Nilotic samples. Our results point to a spatial biodiversity pattern along the Israeli coast, in which the Levantine Province is richer in species, feeding strategies and life habits than the Nilotic Province. The data collected can be used as a baseline for future ecological studies in the area, as they shed light on the under-studied molluscan benthos of the intermediate continental shelf of the Israeli Mediterranean.

L&#x27;analyse des spectres de la malacofaune et des crustacés permet de déduire les territoires exploités (substrats, niveaux de l&#x27;estran) et parfois les techniques de collecte. Deux amas coquilliers du Mésolithique final du sud de la Bretagne (France) ont été analysés. Témoins du mode ...

Le milieu marin est un environnement phylogénétiquement très diversifié et pourtant seulement espèces formellement décrites sont marins (Biggs, 1994). Les mollusques entre autres les gastéropodes, leur vaste répartition dans le monde et leur importance biologique, ont depuis toujours suscité l’intérêt des scientifiques vu qu’ils sont situés à plusieurs niveaux de la biologique, ont depuis toujours suscité l’intérêt des scientifiques vu qu’ils sont situés à plusieurs niveaux de la chaine trophique, ce qui accroit d’avantage leur rôle déterminant dans le fonctionnement des écosystèmes. Parmi ces gastéropodes, le genre Patella, qui regroupe plusieurs espèces dont 5 Bien que ces espèces se partagent le littoral rocheux, elles possèdent des caractéristiques écologiques et morphologiques bien différentes. qui dépendent essentiellement des caractéristiques biologiques intrinsèques des espèces, des conditions hydrodynamiques du milieu et de l’impact de différentes forces évolutives.

A checklist of all taxa of phylum Mollusca stored inside WMSDB.
Fossil only taxa are also included.

This document includes 319.935 taxa:
Family=1.931, Genus=19.080, Subgenus=3.197, Species=135.500, Variety=81.074
synonym/omonym:
345 for Family, 8.784 for Genus/Subgenus and 70.024 for Species/Variety

6109 pages, 55 MB

Exceptionally preserved fossils provide crucial insights into extinct body plans and organismal evolution. Molluscs, one of the most disparate animal phyla, radiated rapidly during the early Cambrian period (approximately 535–520 million years ago (Ma)). The problematic fossil taxa Halkieria and Orthrozanclus (grouped in Sachitida) have been assigned variously to stem-group annelids, brachiopods , stem-group molluscs or stem-group aculiferans (Polyplacophora and Aplacophora), but their affinities have remained controversial owing to a lack of preserved diagnostic characters. Here we describe a new early sachitid, Calvapilosa kroegeri gen. et sp. nov. from the Fezouata biota of Morocco (Early Ordovician epoch, around 478 Ma). The new taxon is characterized by the presence of a single large anterior shell plate and polystichous radula bearing a median tooth and several lateral and uncinal teeth in more than 125 rows. Its flattened body is covered by hollow spinose sclerites, and a smooth, ventral girdle flanks an extensive mantle cavity. Phylogenetic analyses resolve C. kroegeri as a stem-group aculiferan together with other single-plated forms such as Maikhanella (Siphogonuchites) and Orthrozanclus; Halkieria is recovered closer to the aculiferan crown. These genera document the stepwise evolution of the aculiferan body plan from forms with a single, almost conchiferan-like shell through two-plated taxa such as Halkieria, to the eight-plated crown-group aculiferans. C. kroegeri therefore provides key evidence concerning the long debate about the crown molluscan affinities of sachitids. This new discovery strongly suggests that the possession of only a single calcareous shell plate and the presence of unmineralised sclerites are plesiomorphic (an ancestral trait) for the molluscan crown.