Search publications of the members of the Royal Belgian institute of natural Sciences
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Wutuchelys eocenica n. gen. n. sp., an Eocene stem testudinoid turtle from Wutu, Shandong Province, China
- We describe here a new turtle from the early Eocene of Wutu, Shandong Province, China. This turtle with a full row of well-developed inframarginal scutes is assigned to the basalmost testudinoids while stem testudinoids were believed to disappear by the Palaeocene–Eocene boundary. This account shows that stem testudinoids crossed this boundary in their original range. The first comprehensive phylogenetic analysis of stem and modern testudinoids performed here demonstrates that the stem testudinoids, previously placed in the family ‘Lindholmemydidae’, do not form a monophyletic group, and the two major clades of testudinoids (Emydidae and Geoemydidae+Testudinidae) split one from another well before the Palaeocene/Eocene boundary, prior to the Late Cretaceous.
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A gymnodont fish jaw with remarkable molariform teeth from the early Eocene of Gujarat, India (Teleostei, Tetraodontiformes)
- The lower jaw of a gymnodont fish collected from the lower Eocene Cambay Shale Formation in Gujarat Province, western India, has fused dentaries without a beak and a remarkable series of teeth that are unique among all known fossil and living Tetraodontiformes. The teeth are molariform, with raised spokes radiating inward from the emarginated peripheral edge of the crown. Tooth development is intraosseous, with new teeth developing in spongy bone before they erupt and attach to the dentary by pedicels. Although many of the 110 tooth loci in the fossil have lost their teeth, in life the teeth would have grown to fit tightly together to form a broad and continuous crushing surface. The estimated age of the Cambay Shale vertebrate fauna is ca. 54.5 Ma, making the jaw the second oldest confirmed gymnodont fossil. Preliminary comparisons with extant taxa of gymnodonts with fused dentaries (e.g., Diodon, Chilomycterus, and Mola) show detailed similarities in jaw structure, but further study of the dentition is needed to better understand the evolutionary position of the new fossil. We describe the new gymnodont as yAvitoplectus molaris, gen. et sp. nov., in yAvitoplectidae, fam. nov., and place the family as incertae sedis within Gymnodontes.
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Phloeosinus rudis Blanford, 1894, scolyte invasif et nouveau pour la faune belge (Coleoptera, Curculionidae, Scolytinae)
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New extralimital record of a narwhal (Monodon monoceros) in Europe
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Het Menapisch varken: de terugkeer van een lang verdwenen huisdier?
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Mobility and origin of camels in the Roman Empire through serial stable carbon and oxygen isotopes variations in tooth enamel
- Although camels are not indigenous to Europe, they have been found at several sites from several Roman provinces dating from the beginning of the 1st century AD onwards. It must have been beneficial to bring them there. Based on finds of remains from juvenile individuals (e.g. from Tanais), it has been suggested that the Romans might have systematically bred camels within Europe. For this study, we took serial samples of the enamel of four camels from European sites (Innsbruck-Wilten, Mamer-Bertrange, Tongeren, and Trier) dating to the 2nd - 4th century AD. We measured the relative abundances of carbon and oxygen isotopes of the carbonate fraction from the tooth enamel. The continuous record of oxygen and carbon isotopic composition of the intra-tooth enamel serial samples reflects the climate and habitat in which an individual lived during the time of tooth mineralization. We used these data to make a rough evaluation of the areas of origin consistent with the relative abundances of the isotopes from the enamel of the camels and attempt to reconstruct their life history and mobility behavior based on the different ecological characteristics of the habitats represented in the isotopic data. Furthermore, the data can function as an additional proxy for species determination, due to the different habitats of Camelus bactrianus and Camelus dromedarius. This work also yields interesting insights on the similarities in the mobility pattern of the camels from Mamer-Bertrange and Trier. In combination with archaeological evidence, it was possible to tentatively connect them with specific military units, i.e. the detachments of the Legio VIII Augusta.
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Analyse van de dierlijke resten uit de vroegmiddeleeuwse landelijke site Het Kamp in Gentbrugge (Oost-Vlaanderen)
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Analyse van de dierlijke resten uit de middeleeuwse-postmiddeleeuwse site Vleminckveld in Antwerpen
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Analyse van de dierlijke resten uit de laat- en postmiddeleeuwse site van de Nieuwstraat, Veurne (West-Vlaanderen)
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Assessment van zaden en vruchten uit een beerputstaal van de site Hombeek (Mechelen) - Bankstraat
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Anthracologisch onderzoek van twee houtskoolbranderskuilen uit Herzele - Solderhout
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Anthracologisch onderzoek van acht Romeinse crematiegraven uit Damme - Stakendijke
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Anthracologisch onderzoek van twee houtskoolbranderskuilen uit Ardooie - Sprietstraat + Stene
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Assessment van zaden en vruchten uit afzettingslagen van de vliet de Melaan op de site ‘Mechelen – Zakstraat’
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Astronomical pacing of flint beds in the European chalk sea (type-Maastrichtian, Upper Cretaceous)
- Upper Cretaceous chalk deposits, commonly containing flint nodules and bands, are found all over north-west Europe. The question still stands, however, how these flints are formed and whether the pacing of these often rhythmically distributed flint beds can be astronomically controlled. To address this question, we investigated a Maastrichtian chalk succession near Hallembaye (BE) in the type-area around Maastricht (NL). The Hallembaye section is characterized by a gradual change in lithology varying from greyish chalk with rare occurrences of flint nodules towards more pure, whitish chalk with clearly expressed flint bands. Micro X-Ray Fluorescence measurements were carried out on powdered chalk samples to determine their elemental composition. ‘Flint Scores (FS)’ were attributed to quantify the distribution of flints in function of the stratigraphic height. Using an integrated stratigraphic approach, we performed a cyclostratigraphic study to evaluate a potential astronomical imprint. The Ti/Al signal, a diagenesis-resistant proxy reflecting changes in the composition of detrital influx or the provenance thereof, reveals short-scale fluctuations superimposed on a gradually decreasing trend. Time-series and spectral analyses of the Ti/Al signal reveal a dominant 40 kyr obliquity component with its 173 kyr modulation, as well as a weaker precession–eccentricity signal. Analysis of the FS equally suggests an astronomical pacing of the flint layers. We tune the FS record to the stable 173 kyr and 405 kyr astronomical cycles to construct a high-resolution age model in absolute time, complementary to a floating 40 kyr obliquity time scale. The exact mechanisms of the flint formation and its astronomical pacing remains subject of further research but seem most likely to be linked to changes in clay content. Possibly, variations in the influx of detrital material could have influenced local redox conditions as well as the paleoproductivity in the water column.
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Boekbespreking: De Nederlandse breedvoetvliegen en basterdbreedvoetvliegen (Platypezidae & Opetiidae) Entomologische tabellen Volume 10.
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Period of public commentary begins on the revised proposal of species-group level names, and on the proposal of genus-group level names of the Candidate Part of List of Available Names (LAN) in the phylum Rotifera
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Placoderm assemblage from the tetrapod-bearing locality of Strud (Belgium, Upper Famennian) provides evidence for a fish nursery
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Reduced host-specificity in a parasite infecting non-littoral Lake Tanganyika cichlids evidenced by intraspecific morphological and genetic diversity
- Lake Tanganyika is well-known for its high species-richness and rapid radiation processes. Its assemblage of cichlid fishes recently gained momentum as a framework to study parasite ecology and evolution. It offers a rare chance to investigate the influence of a deepwater lifestyle in a freshwater fish-parasite system. Our study represents the first investigation of parasite intraspecific genetic structure related to host specificity in the lake. It focused on the monogenean flatworm Cichlidogyrus casuarinus infecting deepwater cichlids belonging to Bathybates and Hemibates. Morphological examination of C. casuarinus had previously suggested a broad host range, while the lake’s other Cichlidogyrus species are usually host specific. However, ongoing speciation or cryptic diversity could not be excluded. To distinguish between these hypotheses, we analysed intraspecific diversity of C. casuarinus. Monogeneans from nearly all representatives of the host genera were examined using morphometrics, geomorphometrics and genetics. We confirmed the low host-specificity of C. casuarinus based on morphology and nuclear DNA. Yet, intraspecific variation of sclerotized structures was observed. Nevertheless, the highly variable mitochondrial DNA indicated recent population expansion, but no ongoing parasite speciation, confirming, for the first time in freshwater, reduced parasite host specificity in the deepwater realm, probably an adaptation to low host availability.
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A distinct island population of threatened freshwater fish: to split or lump?
- Freshwater fishes in the Balkans display high percentages of endemic species, many being limited to restricted distributions. Their management, for example, through identification of priority areas for conservation or through re-introduction, is hampered by a poor understanding of their taxonomic diversity and interrelationships. We evaluate the identity of a sand goby belonging to Knipowitschia, limited to a single wetland on the Greek island of Zakynthos. Its representatives morphologically differ sufficiently from their congeners to qualify as a separate species. However, in view of the similarity in mitochondrial ribosomal DNA sequences, the evolutionary plasticity of said morphological characters, and in the absence of a taxonomic revision of the Ionian Ecoregion’s Knipowitschia gobies, describing it as a new species seems unjustified and premature. Rather, we advocate that its unique habitus and its vulnerability as the island’s only resident freshwater fish necessitate conservation efforts as a kind of ‘‘phenotypically significant unit’’. We also propose sand gobies as flagships for wetlands in the region. This case study suggests a possible approach for fish conservation prioritization in the region, taking a precautionary angle in order to avoid taxonomic inflation, which is an imminent risk given the importance of nominal species and endemics in conservation policy.
