Search

X-ray diffraction (XRD), Scanning Electron Microscope-Energy Dispersive Spectroscopy (SEM-EDS), and Fourier Transform Infrared Spectroscopy (FT-IR), were applied to analyze the organic matrix of two Molluscan shells. The Mollusca shells are mineral structure and calcium carbonate crystallized as aragonite. The FT-IR spectra showed Alkyl Halide, Alkanes, Alcohols, Amides, Aromatic, and Hydroxyl groups in the organic matrix of the whole (organic and mineral) Molluscan shells. SEM images of particles of the two Molluscan shells at different magnifications were taken. The morphologies of the samples show a flake like structures with irregular grains, their sizes are at micrometric scale and the chemical analysis of EDS indicated that the major elements of Cardita and Gastropoda were C, O, and Ca, consistent with the results of XRD analysis. The results of the analysis of the EDS spectra of the shells showed that the content of most of the powder composition of shells is the element carbon, calcium oxygen, aluminium, and lead peaks that appear on the Cardita and Gastropoda and shells powders tap EDS spectra. The present work examined organic matrix of the selected shells of the heavily polluted and light polluted sites, along Nellore Coast, South East Coast of India. The heavily polluted sites have significantly thickened shells. The data demonstrated the sensitivity of this abundant and widely distributed intertidal fragile environment. Keywords: Mollusca shells, Organic matter, FTIR Spectroscopy, XRD, SEM and EDS analysis

In 2015 the locality Borač-Podolí was newly examined. The locality is situated 8 km NW from the town of Tišnov. A large amount of shallow-water fossils of middle Miocene (Badenian) age was collected. The state of preservation of the material enabled us bivalve borings of ichnogenus Gastrochaenolites which were bored into colonies of hermatype corals and other calcareous hard substrates. In some of these borings, bivalves were found in situ. The borings were determined as Gastrochaenolites isp., Gastrochaenolites orbicularis, Gastrochaenolites lapidicus, Gastrochaenolites dijugus and Gastrochaenolites torpedo. The in situ bivalves were determined as Gastrochaena cf. intermedia, Rocellaria cf. dubia, Hiatella arctica and Cardita calyculata. The first three species probably represent primary borers while Cardita calyculata is probably a secondary user (squatter). Based on an analysis of fossil material, we can assume that borings were created aft er the death of corals during the repeated transport of these bioclasts. It led to colonizing of the whole surface of coral bioclasts. The bioclasts were then moved to deeper water. Transport to water with clay sedimentation enabled the preservation of the bivalves in situ in borings.

The population dynamics of the “cholga” Cardita affinis (Sowerby 1833) from Malaga Bay, Colombia, was studied from December 1999 to February 2002, which included the 1999–2000 La Nina event (LN) and the post-LN period 2001–2002. This climatic deviation caused precipitation anomalies in Malaga Bay. Salinity, precipitation, and sea surface temperature anomalies were highly correlated with the bivalve’s body mass cycle. Irregular spawning events were observed during LN by comparison with the regular period. Individual growth and mortality were found significantly higher during LN than during the post-LN period while longevity was almost twofold lower during LN. Increased mortality was probably related to environmental stress. Individual production and productivity were higher during LN, although the annual biomass was lower than during the post-LN period. These results may be related to higher food availability during LN, which agrees well with the results on growth performance. The observed changes provide a base line for future studies regarding effects of El Nino/LN events on population dynamics of tropical bivalves.

Based on the study of available types and extant collections, this paper provides a systematic revision of the living species of Carditoidea occurring in the Magellan and Perú-Chile Provinces. Out of the 19 nominal species reported for the area, eight species are recognized as valid: Cyclocardia compressa, C. spurca, C. thouarsii, C. velutina, Carditella naviformis,C. semen, C. tegulata and Carditopsis flabellum. Other eight nominal species are regarded as synonyms: Cardita magellanica of Cyclocardia velutina; Carditella pallida of C. tegulata; Cardita australis and Actinobolus philippi of Carditella naviformis; Cardium pygmaeum of Carditella semen; Cardita paeteliana of Cyclocardia spurca; Carditella pallida duodecimcostata of Carditopsis flabellum; and Cardita congelascens of Cyclocardia thouarsii. Furthermore, Cardita malvinae and Cardium parvulum are nomina dubia, and the occurrence of Carditella exulata in Magellanic waters is doubtful. Fil: Güller, Marina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; Argentina Fil: Zelaya, Diego Gabriel. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Bivalve molluscs from the Western coast of Senegal were sampled and measured for their cadmium, copper and zinc concentrations. This part of Africa has not been studied as regards heavy metal concentrations in the molluscs. The collected species are two small African bivalve molluscs, living in the sand: Cardita ajar and Dosinia isocardia; the African mussel Perna perna which is the only mussel of this genus in the Western coast of Africa and the oyster Crassostrea gasar, which lives in mangroves attached to the rhizophores, in the intertidal zone. C. gasar and C. ajar present higher cadmium concentrations, respectively 6.82±0.54 and 13.77±0.80 μg Cd/g (d.w.) than the two other species (D. isocardia: 3.88±0.31 μg/g and P. perna 2.37±0.22 μg/g. Copper and zinc concentrations are in the range of the published values for C. gasar and P. perna collected elsewhere in Africa. The results suggest that cadmium may be present in high concentrations in Senegalese waters where upwellings occur. Keywords: Metals, Molluscs, Senegal, Mauritania, Crassostrea gasar, Perna perna, Cardita ajar, Dosinia isocardia, Donax rugosus

New facts relating to the geology of the Paxos and Ionian zones, the outermost zones of the Hellenide structure of western Greece, are reported. In Leukas island, a shaly bituminous dolomite formation has been found to occur below the Cardita guembeli limestones which had previously been thought to be the oldest in Greece. In the eastern part of Cephallonia island there is evidence of transition between the Paxos and Ionian zones, represented principally by the extension of the limestone facies through the Oligocene and the presence of lower Miocene Flysch. The age of the gypsum found in the discordant upper Tertiary deposits is a problem; from their structural position and the nature of the associated limestone breccias, they could be Triassic or even Permian emplaced in two stages by a sort of diapirism.

In a former paper published in the Quarterly Journal of the Geological Society of London (vol. ii. p. 405, May 1846), I stated that the limestone containing abundantly the Nummulites Mantelli , Morton, which occurs near Suggesville, Clarksville, and other places between the rivers Alabama and Tombecbee, in the State of Alabama, was a member of the Eocene tertiary group, and that so far from constituting any part of the cretaceous formation, as had formerly been imagined, it holds in reality a place high up in the Eocene series of the South. In the same memoir I gave a section extending from Claiborne through Suggesville and Macon to the west of Clarksville, Alabama, in which the position of the so-called nummulitic limestone was explained. It was stated to be newer than all the beds of the well-known Claiborne Bluff, and I mentioned that “the bones of the gigantic cetacean called Zeuglodon by Owen were everywhere found in Clarke County, in a limestone below the level of the nummulitic rock and above the beds which contain the greater number of perfectly preserved eocene shells, such as Cardita planicosta and others.”

THE Deccan Traps comprise one of the largest volumes of basaltic volcanics known, covering an area of about 500,000 sq. km in western and central India. Their age and range of age have been the subjects of much debate in the past. In summing up the stratigraphic evidence for the age of the traps, Krishnan states1 that their base lies, in various places, on marine beds of Danian age (Cardita beaumonti beds), of Cenomanian to Senonian age (Bagh beds), and of roughly Turonian age (Lametas). Non-marine sediments within the Deccan Traps (Intertrappean beds) contain fossil plants and fish that are thought to be of Palaeocene age. In several places sediments overlying the traps are Palaeocene in age.