The Royal Belgian Institute of Natural Sciences(RBINS) holds a collections of well over 7000 Cretaceous fossils that were collected by the RBINS staff in the early 1930ies during the construction of several coal mine shafts in the eastern part of the Belgian Campine Basin. These fossils include ammonites, nautilids, belemnites, bivalves (inoceramids and other), gastropods, crustaceans, brachiopods, echinoderms and other. The majority of the material is from mine shafts 1 and 2 of the Houthalen and Zolder mines, in-between 400 and 600 m below surface. Both mines are located in the eastern part of the Campine Basin. Since their discovery, the majority of this material has never been thoroughly studied and published. Detailed listings of the fauna and an overview in relation to the stratigraphy are absent. In the 1930ies, by the varying amounts of glauconite, chalk, sand, sandstone and the ‘Gyrolithes’ ichnofossils, the sediments between 400 and 600 m depth were interpreted as belonging to the ‘Smectite de Herve’ facies. Therefore, early students referred to fossils from this locality as Campanian in age, while more recent studies and ongoing work document Santonian to Maastrichtian ages with (from bottom to top) the Asdonk and Sonnisheide Members (Vaals Formation), the Zeven Wegen, Beutenaken Marl, Beutenaken Chalk, Vijlen and Lixhe Members (Gulpen Formation). The CRETACAM project aims for fully documenting the lithological, stratigraphical, paleontological and paleo- ecological changes in the Santonian to Maastrichtian sequence of the eastern part of the Campine Basin. In a first step, all locality information of all 7000 specimens was digitalized. In a second and ongoing step, the taxonomy of all specimens will be revised by an international team of paleontologists.
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Marine invertebrates with long-lived planktonic larvae are assumed to have high dispersal potential and broad-scale gene flow. They are thought to disperse over long distances and to be genetically homogeneous over large areas. The periwinkle Melarhaphe neritoides which ranges along much of the European coastline, is such a species. Its long-lived planktonic larval phase lasts 4-8 weeks and previous allozyme studies have shown very little to no population genetic differentiation along the European coast, even over distances of thousands of kilometers. However, a growing number of studies based on DNA markers suggest that there is a poor correlation between pelagic larval duration (PLD) and the level of population genetic differentiation (r² = 0.29). Nevertheless, recent work reaffirms that PLD might still be a good predictor of population genetic differentiation as a function of geographic scale, if based on unbiased FST estimates and appropriate sampling sizes. We explored these conflicting views by assessing mtDNA (COI, 16S, Cytb) differentiation among five intensively-sampled populations of M. neritoides in the Azores. In contrast with previous allozyme data, our mtDNA data reveal remarkably high genetic diversity and differentiation among M. neritoides populations, even those as close as 50 km. Even at this scale, populations do not seem to share haplotypes, despite the assumed high potential of broad-scale gene flow in M. neritoides. Hence, the relationship between PLD and dispersal potential or the level of population genetic differentiation, is indeed not straightforward.
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