Families Of Molluscs Research Articles

The Invertebrates of The Romualdo Formation, Araripe Basin: Analysis of Paleoecological and Paleogeographical Data

Fossil invertebrates are good paleoenvironmental indicators due to their sensitivity to abiotic conditions, which contributes to the understanding of the Aptian-Albian of the Araripe Basin. However, much of the paleoecological and paleobiogeographical information on these organisms is scarce in the literature. The aim of this paper is to compile relevant data on the macroinvertebrates of the Romualdo Formation and to analyze and point out gaps in knowledge. To achieve this, extensive bibliographical research was carried out, using scientific publications based on the families of Spinicaudata, echinoids, gastropods, bivalves, shrimps and crabs of the Romualdo Formation and their distribution in Brazil and globally throughout the Aptian-Albian, using specialized online databases. Paleoecological and paleogeographical data were compiled for 46 invertebrate taxa, highlighting those with better studied routes of origin. Thus, it was possible to highlight the lack of data regarding the way of life of certain mollusc families and systematic problems regarding the identification of the families of several species of shrimp. Finally, the predominance of taxa from marine (34), brackish (7) and lacustrine (5) waters was shown. Of these, 18 taxa have a typical tethyan distribution and another 12 also present occurrences in the Austral, Boreal or both domains. The only typical freshwater group was Spinicaudata, marking environments with little or no marine influence and with rare occurrences during the Aptian-Albian.

CROSSTALK OF CONSERVATION OF SEQUENCES OF miRNAs AND ENZYMATIC MACHINERY OF miRNAs PRODUCTION IN AMPULLARIIDAE

BACKGROUND: The Ampullariidae family of molluscs is an emerging model for evolutionary studies due to its high diversity, ancient history and wide geographic distribution. miRNAs are essential for the development of the organism, as they help and act in the control of gene expression. The analysis of miRNAs in molluscs, especially in the family Ampullariidae, is especially important due to the low representativeness of analyzed species and the possibility of analyzing the conservation of miRNAs among ampullariids species. OBJECTIVE: Identification and characterization of miRNAs (precursors and matures) and their processing pathway genes. METHODS: Computational prediction and characterization of miRNAs and genes involved in the miRNA pathway were performed using public database of Lanistes nyassanus, Marisa cornuarietis, Pomacea canaliculata and Pomacea maculata. The in silico analysis was performed using a robust algorithm to identify and characterize miRNAs and their precursors in genome of ampullariids species. To search for the putative proteins involved in the miRNA biogenesis the putative proteomes from 4 Ampullariids species and Blastp tool were used. Characterization of conserved protein domains was performed using the PFAM and CDD. Phylogenetic analyzes were performed for the ampullariids miRNA precursors and their orthologs and also for the putative ampullariids proteins involved in the miRNA pathway and their orthologs using MEGA program. FINDINGS: 141 pre-miRNAs and 162 mature miRNAs were identified in the genome of L. nyassanus, 279 pre-miRNAs and 297 mature miRNAs in the genome of M. cornuarietis, 269 pre-miRNAs and 296 mature miRNAs in the genome of P. canaliculata and 299 pre-miRNAs and 316 mature miRNAs in the genome of P. maculata. We identified and characterized 24 putative key proteins involved in the miRNA pathway including Argonaute, DICER, DROSHA and EXPORTIN protein families in the predicted proteome of the 4 ampullariids. The data obtained in this work will support studies of phylogeny, population divergence, speciation and patterns of diversity in the Ampullariidae Family. MAIN CONCLUSIONS: The searching for novel miRNAs and their processing pathway genes in 4 species of ampullariids was able to predict new structures expanding the study of miRNAs in molluscs and in Ampullariidae family, as well as open an avenue to study the roles of miRNAs in the organisms.

OysterDB: A Genome Database for Ostreidae.

The molluscan family Ostreidae, commonly known as oysters, is an important molluscan group due to its economic and ecological importance. In recent years, an abundance of genomic data of Ostreidae species has been generated and available in public domain. However, there is still a lack of a high-efficiency database platform to store and distribute these data with comprehensive tools. In this study, we developed an oyster genome database (OysterDB) to consolidate oyster genomic data. This database includes eight oyster genomes and 208,923 protein-coding gene annotations. Bioinformatic tools, such as BLAST and JBrowse, are integrated into the database to provide a user-friendly platform for homologous sequence searching, visualization of genomes, and screen for candidate gene information. Moreover, OysterDB will be continuously updated with ever-growing oyster genomic resources and facilitate future studies for comparative and functional genomic analysis of oysters ( http://oysterdb.com.cn/ ).

Diversity and species richness of land snails inhabiting an impacted macro-zone-Mfamosing limestone hill in Sub-Saharan Region

The land snail diversity and abundance and some ecological aspects of the fauna in a threatened limestone hill in Mfamosing, Cross Rivers state, Nigeria was investigated between May 2017 and June 2018. Twelve plots of 10 m x 10 m each using a combination of leaf litter in the forest floor (litter and topsoil in a total of ninety sample bags) were sampled from which shells were extracted by handpicking. A total of 289 (two hundred and eighty-nine) specimens representing twenty-three species in seven molluscan families were recorded. The carnivorous Streptaxidae family dominated the fauna regarding species richness while the family Urocyclidae dominated species abundance. The families Eucolinidae and Aillyidae accounted for the least dominant species. The family Streptaxidae with seven species accounted for over 30% of the mollusk abundance, while Urocyclidae had the highest number of individual specimens. True estimates of diversity using Chao2 and second-order Jack-Knife estimators yielded 25 and 24 species respectively. The Land Snail diversity in Mfamosing limestone hill when compared with those from other parts of Nigeria (Okomu in Edo State) and some other parts of the world (Sabah, Malaysia) is relatively high, with moderate levels of species abundance, showing relatively high differentiation, local dominance and endemism by few species. This reveals that Mfamosing limestone hill is one of the biodiversity hotspots for terrestrial mollusks and requires urgent conservation measures, given the current rate of Limestone quarrying in the region.

The diversity and abundance of terrestrial snails in yankari game reserve, bauchi state, Nigeria

Land snails represent one of the most important groups of invertebrates in terrestrial ecosystems; this study was aimed at determining the distribution and abundance of land snails in Yankari Game Reserve Bauchi State, Nigeria. Land snails were investigated in Yankari using a combination of direct search and litter sieving techniques. 10 plots were sampled randomly within an area of 100m × 100m so as to have a good spread of each site. Soil sample were collected within each of the plots and analyzed for soil pH, total nitrogen, organic carbon, calcium and moisture content. A total of 103 specimens comprising of six species belonging to four molluscan families were collected from ten plots in Yankari Game Reserve. This showed that the molluscs were moderately diverse. The family, Achatinidae dominated the fauna in Yankari Game Reserve. This study has revealed that the land fauna in Yankari are moderately diverse with low densities. The result indicates that not all the sampling areas of the reserves had much species; it is therefore presumed that there may be richer areas of land snails which were not sampled in both sites.

INTEGRATING EXPERIMENTS WITH SUBTIDAL DEATH ASSEMBLAGES TO UNVEIL THE PREDATORY HABITS OF MURICID GASTROPODS FROM THE SOUTHEASTERN PACIFIC

Abstract As quantitative tools, drill holes have been used to calculate predation frequencies in time and space. These traces can also inform predator preference and some strategies predators use to drill on prey (e.g., edge drilling, site stereotypy, or alternative modes of predation when there is no drill hole). In this study, our goal was to leverage the informative power of drill holes to characterize the predatory habits of muricid gastropods from the central coast of Chile. We integrated information from experiments and death assemblages (DAs) to unveil the predatory strategy of Ancathina monodon, Crassilabrum crasilabrum, and Concholepas concholepas on the mobile gastropod Tegula tridentata and the sessile bivalve Perumytilus purpuratus. Experiments supported previous findings for predatory strategies (basal spine for Ancathina and alternative modes of predation for Concholepas), and showed the stereotypic predation of Crassilabrum on Tegula—a herbivore that is devastating subtidal kelp forests. Based on drill holes from DAs, at least 11 molluscan families are consumed by muricids in these communities. DAs also helped validate the stereotypic predation of Crassilabrum on Tegula, as drill holes were found in the same position both in experiments and DAs. Despite their thinner shells, mytilids were well represented in DAs and were found with drill holes in the five locations sampled. We describe for the first time the predatory strategy of Crassilabrum in Chile and confirm that muricids other than Concholepas are active predators on subtidal rocky habitats from the southeastern Pacific Ocean, a region that is still understudied.

Terrestrial molluscs species richness and diversity in Gashaka - Gumti National Park, Taraba State, Nigeria.

To assess the biodiversity of terrestrial molluscs in Gashaka-Gumti National Park, a four plot (20 x 20m) each within the park were sampled by searching the forest floor, tree trunk, fallen logs, root facies, and vegetation for the presence of mollusks. The species found were collected by hand picking.A total of 819 specimens comprising 22 species belonging to six molluscan families were collected from four plots. Each plot yielded between 8 to14 species (Mean:10, Standard Deviation:2.71) and 33 to 683 individuals (Mean:204.75, Standard Deviation :319.09). The most abundant species in the park was Curvella sp. represented by 683 individuals (79.4%) of the total sampled species. The most abundant family is Streptaxidae represented by 8 species (36.4%) of the total sample.The sample intensity was 37.22 while the Inventory Completeness is 79.31%. Eleven (11) species occurred as singleton across plots while ten (10) species occurred as doubleton across the four plots sampled.The Whittaker Index is 4.00. The rarefaction curve nearly reached an asymptote as sampling stopped. The nonparametric estimator Chao 2 and jackknife 2 were 28.05 and 33.99 of all sample collected. The dendogram of similarity by plots using Bray-Curtis similarity of index show the close relationship of two plots in terms of species. It shows that there is no significant difference between plots. Plot 1 and 4(P=0.4329), Plot 2 and 3 (P=0.9595), Plot 1 and 3 (P=0.2390), Plot 2 and 4 (P= 0.78). In conclusion, the family Subulinidae has the most abundant individuals with 733 individuals representing 89.4% while Streptaxidae occur as the most abundant family with 8 species of the total sample.

Chemicals behind the use of Strombus tricornis opercula in traditional sudanese perfumery and medicine

Strombidae is one of the major molluscan families in Sudan and due to their opercula, has tremendous economic value. In traditional Sudanese homemade perfumes and body care cosmetics, Strombidae family operculum is one of the main ingredients. Their fumigation generates a charming odor preferred by Sudanese people, used for body smoke baths by married women. Moreover, these fumes are believed to treat several gynecological disorders. In this study, we attempted to confirm the presence of volatiles with pleasant odors and compounds with pharmaceutical importance in the Strombidae opercula. Volatiles from the smoke and soak extracts of the burned opercula were analyzed using gas chromatography-mass spectrometry (GC-MS). Furthermore, polar components from the methanol extract of opercula powder were isolated using high-performance liquid chromatography (HPLC) and identified by nuclear magnetic resonance (NMR), electrospray ionization mass spectrometry (ESI-MS), and UV spectra. The elemental and metal contents were analyzed using inductively coupled plasma-mass spectrometry (ICP-MS). GC-MS analysis revealed several phenols, aldehydes, ketones, and other functional fragrant and volatile constituents. Further, two compounds were purified from the methanol extract of Strombidae opercula, and named compounds B and D, which were identified as cyclo-(Tyr-Gly) and 4-hydroxybenzaldehyde, respectively. ICP-MS analysis revealed the presence of various elements and metals at different levels. These findings support the historical and traditional practices and usage of the Strombidae opercula in therapeutic and esthetic products. The opercula contains many biologically active compounds and produces smoke containing volatile scent compounds, which might provide alternative pharmaceuticals and cosmetic ingredients that can cooperate to improve the manufacturing of numerous medical products.

Nomenclator, geographic and stratigraphic distribution of the family Triphoridae (Mollusca: Gastropoda).

The microgastropod family Triphoridae is one of the five most diverse marine molluscan families. It likely hosts a few thousand species worldwide, but its taxonomy has long been considered challenging due to the high diversity and subtle morphological characters needed for species delimitation. Consequently, only a small portion of the species appears to be formally described to date. However, further taxonomic work should be based on robust knowledge on the numerous names introduced so far. In this perspective, we have here compiled a list of all published names that can be attributed to the fossil and extant Triphoridae. We list 958 species and 75 genus names, of which 771 are known as extant species and 146 as fossil species, 41 are known from both fossil and extant records. We provide information on type locality and horizon, type material, synonymy and homonymy. Importantly, based on the review of hundreds of publications, we provide a preliminary overview of the geographic and stratigraphic distribution.

Terrestrial gastropod diversity, distribution and abundance in areas with and without anthropogenic disturbances, Northeast Algeria

Belhiouani H, El-Hadef El-Okki M, Afri-Mehennaoui FZ, Sahli L. 2019. Terrestrial gastropod diversity, distribution and abundance in areas with and without anthropogenic disturbances. Biodiversitas 20: 243-249. The objective of this study was to establish an inventory of terrestrial gastropods from different sites in the northeast of Algeria. Several points were sampled from five various areas relatively affected by human activity. Areas prospected were an industrial area (El-Hadjar, Annaba), a mining area (Djebel Hamimat, Oum-El-Bouaghi), an urban area (B’kira, Constantine), a mountainous area (Ibn Ziad, Constantine) and a sub-mountainous area (Ibn Badis, Constantine). A total of 11 species and 2632 individual land snails belonging to six molluscan families (Helicidae, Hygromiidae, Sphincterochilidae, Achatinidae, Enidae, and Pomatiidae) and 10 genera were found in all habitats. The highest density was recorded in the mountainous area with 1270 individuals and 10 species, whereas the lowest value was recorded in the mining and the industrial areas with 3 and 4 species respectively. The malacofaunal diversity was also determined, Shannon’s index, Simpson’s index, and equitability index are higher in the mountainous zone of Ibn Ziad with 1.87, 0.82 and 0.78 respectively, and lower in the mining area of Djebel Hamimat, with 0.60, 0.33, and 0.54. The dispersion and density of species appear to be contingent upon several factors among which soil properties, height, climate conditions and certainly anthropogenic disturbance.

Land Snail Community Structure and Diversity in Unprotected and Protected Forest Areas of Ekiti State, Nigeria

The community structure and diversity of land snail fauna in Ekiti State was investigated in two protected and one unprotected tropical rainforest ecosystems. Twelve (12) plots measuring 20m x 20m each were surveyed in each forest area, using direct search and leaf-litter filtering techniques. A total of 1095 specimens representing 43 species in 9 molluscan families were collected. Each forest area yielded between 190 and 584 individuals. Alpha diversity ranged from 27 to 32 species, with species richness highest in Ogbesse Forest Reserve and least in the unprotected forest area at Ipole Iloro. The herbivorous Subulinidae and carnivorous Streptaxidae were the most represented families as regards species richness, with family Subulinidae (45.20%) being the most abundant numerically. The most abundant species was Thapsia oscitan of the family Urocyclidae, contributing almost 15% of the total number of individuals. Six (6) species occurred as singleton while 4 species occurred as doubleton. There was considerable variation in species richness between the three sampled forest areas, Cluster analysis formed two groups, Analysis of similarity (ANOSIM) between clusters using the BrayCurtis similarity index gave values of R=1, P=0.34, indicating that the study areas were well separated. The high diversity and abundance recorded from this study reveal the study area is rich in land snails, thus, efforts should be made to maintain the ecological integrity of the protected areas as well as improve biodiversity conservation and management in the unprotected areas.

Conidae (Mollusca, Gastropoda) of Lakshadweep, India.

Lakshadweep, the northernmost region of the Chagos-Maldives-Lakshadweep group of islands located southwest of the Malabar coast of India in the Arabian Sea, is the only chain of coral atolls in India. This paper documents the diversity of the molluscan family Conidae from the seas around all ten inhabited islands of Lakshadweep. Of the 78 species of cone snails now reported from Lakshadweep, 49 were recorded in this study. Threeof these had not previously been reported from India, and four are newly reported from Lakshadweep. The results increase the number of Conidae species known from Lakshadweep by 10%.

Spondylids of Eastern Pacific Ocean

Fil: Lodeiros, Cesar. Centro Nacional de Acuicultura e Investigaciones Marinas. Escuela Superior Politecnica del Litoral. Guayaquil; Ecuador. Instituto Oceanografico de Venezuela Universidad de Oriente; Venezuela

Female-dependent transmission of paternal mtDNA is a shared feature of bivalve species with doubly uniparental inheritance (DUI) of mitochondrial DNA

Several species from a number of bivalve molluscan families are known to have a paternally transmitted mitochondrial genome, along with the standard maternally transmitted one. The main characteristic of the phenomenon, known as doubly uniparental inheritance (DUI), is the coupling of sex and mtDNA inheritance: males receive both genomes but transmit only the paternal to their progeny; females either do not have the paternal genome or, if they do, they do not transmit it to their progeny. In the families Mytilidae and Veneridae, both of which have DUI, a female individual is either female-biased (it produces only, or nearly so, female progeny), male-biased (it produces mainly male progeny) or non-biased (it produces both genders in intermediate frequencies). Here we present evidence for a same pattern in the freshwater mussel, Unio delphinus (Unionidae). These results suggest that the maternal control of whether a fertilized egg will develop into a male or a female individual (and the associated feature of whether it will inherited or not inherit the paternal mtDNA) is a general characteristic of species with DUI.

Cypraeidae: How Well-Inventoried is the Best-Known Seashell Family?*

Cowries (Cypraeidae) are diverse and occur in all tropical and some temperate seas, from shallow waters to the deep sea. There is a vast literature documenting the distribution, taxonomy, and shell variation, among many other topics. Because of its popularity among shell collectors, amateurs have contributed more to the cowrie literature than to most molluscan families. Traditionally, taxa have been described based on shell characters, and the majority of species descriptions continue to be published in non-peer-reviewed journals, magazines and books. Molecular studies in the last two decades have largely confirmed phylogenies based on morphology and anatomy. Currently, 245 species and 166 subspecies (or 411 operational taxonomic units) are recognized in 48 genera in the family. Despite being the best-known seashell family, the discovery curve suggests that there are still more taxa to be discovered. A review of the knowledge of the family is presented, and information on each genus is summarized.

Terrestrial Mollusc Species Richness and Diversity in Omo Forest Reserve, Ogun State, Nigeria

The terrestrial mollusc species richness and diversity in Omo Forest Reserve, Ogun State, Nigeria, was studied using a combination of direct search and leaf-litter sieving techniques. In total, 28 species and 639 individuals in 7 molluscan families were collected from 17 plots of 400 m2 each. Species richness varied from 3 to 14 (mean 8.59) and the number of individuals from 8 to 67 (mean 37.59) per plot. Species richness was dominated by the carnivorous Streptaxidae (36%) and herbivorous Subulinidae (32%), and numerical abundance by the Subulinidae (56%) and Streptaxidae (32%). The most abundant species was the large subulinid, Subulona pattalus, contributing almost 25% of the total number of individuals. Terrestrial molluscs with small populations and narrow distributional ranges are at great risk of local extinction if forest destruction continues unabated. Studies on the molluscan diversity in Omo Forest Reserve will assist in producing an inventory for biodiversity conservation management in Nigeria.

Composition of macrobenthos in the Wouri River estuary mangrove, Douala, Cameroon

The macrobenthos of mangroves is dominated by crabs and molluscs, which have a significant ecological role in terms of the structure and function of mangroves. The aim of this study was to determine the abundance and biological diversity of these groups in the Wouri River estuary mangrove in Douala, Cameroon. Three methods of crabs capture (excavation, sight harvest and visual count) were used in 10 × 10 m2 plots for the crabs and quadrats of 1 × 1 m2 were employed for mollusc counts. In all, 24 species, evenly distributed between the two groups, were collected. Five families of crabs and six families of molluscs were identified. Sesarmidae (eight species) and Pachymelaniidae (four species) were best represented in terms of species richness, whereas Sesarmidae (94.6%) and Potamididae (45.6%) were the most abundant taxa. The inventory of macrobenthos of mangroves in Cameroon currently consists of 60 species, including nine (three crabs and six of molluscs) reported from this study.

Molecular characterization of a novel tetraspanin from the oyster, Crassostrea ariakensis: Variation, localization and relationship to oyster host defense

We identified a tetraspanin family member gene, named Ca-TSP, in the oyster Crassostrea ariakensis and found that the transcription profiles of Ca-TSP were variable in the oyster hemocytes. Three distinct patterns of variation of Ca-TSP were observed. Using immunofluorescence and immunoelectron microscopy, we show that Ca-TSP was present in granules and in vesicular structures of the oyster hemocyte. Sequence analysis, structural features and immunogold electron microscopy showed that Ca-TSP is an integral membrane glycoprotein of granules of hemocyte and may be a novel CD63-like gene of the tetraspanin family of molluscs. The gene expression analysis of Ca-TSP using isolated oyster hemocytes, was done following challenge of the oysters with LPS and Poly I:C. The Ca-TSP mRNA levels increased in hemocytes in the first 12 h after LPS and Poly I:C stimulation, and decreased after the addition of H2O2. Western blot analysis using anti-Ca-TSP antibody indicated that gene expression and protein levels were similar. The recombinant Ca-TSP was found to significantly inhibit hemocytes aggregation. Our results suggested that Ca-TSP participates in the innate immunity of the oyster.

Large‐scale species delimitation method for hyperdiverse groups

Accelerating the description of biodiversity is a major challenge as extinction rates increase. Integrative taxonomy combining molecular, morphological, ecological and geographical data is seen as the best route to reliably identify species. Classic molluscan taxonomic methodology proposes primary species hypotheses (PSHs) based on shell morphology. However, in hyperdiverse groups, such as the molluscan family Turridae, where most of the species remain unknown and for which homoplasy and plasticity of morphological characters is common, shell-based PSHs can be arduous. A four-pronged approach was employed to generate robust species hypotheses of a 1000 specimen South-West Pacific Turridae data set in which: (i) analysis of COI DNA Barcode gene is coupled with (ii) species delimitation tools GMYC (General Mixed Yule Coalescence Method) and ABGD (Automatic Barcode Gap Discovery) to propose PSHs that are then (iii) visualized using Klee diagrams and (iv) evaluated with additional evidence, such as nuclear gene rRNA 28S, morphological characters, geographical and bathymetrical distribution to determine conclusive secondary species hypotheses (SSHs). The integrative taxonomy approach applied identified 87 Turridae species, more than doubling the amount previously known in the Gemmula genus. In contrast to a predominantly shell-based morphological approach, which over the last 30 years proposed only 13 new species names for the Turridae genus Gemmula, the integrative approach described here identified 27 novel species hypotheses not linked to available species names in the literature. The formalized strategy applied here outlines an effective and reproducible protocol for large-scale species delimitation of hyperdiverse groups.

Polypropionates from Bulla occidentalis: chemical markers and trophic relationships in cephalaspidean molluscs

A chemical investigation on the cephalaspidean Bulla occidentalis from the Gulf of Mexico led to known niuhinones A ( 1) and B ( 2) along with a new acyclic polypropionate, named niuhinone C ( 3). A complete NMR assignment of niuhinone A has been achieved by spectroscopic experiments, thus revising the Δ 14 configuration. The occurrence of structurally related polypropionates in Bullidae species from different geographical areas is in agreement with a de novo origin in this family of molluscs and adds a further piece of evidence on prey–predator relationships among cephalaspideans.