Bivalves record seasonal environmental changes in their shells, making them excellent climate archives. However, not every bivalve can be used for this end. The shells have to grow fast enough so that micrometre- to millimetre-sampling can resolve sub-annual changes. Here, we investigate whether the bivalve Angulus benedeni benedeni is suitable as a climate archive. For this, we use ca. 3-million-year-old specimens from the Piacenzian collected from a temporary outcrop in the Port of Antwerp area (Belgium). The subspecies is common in Pliocene North Sea basin deposits, but its lineage dates back to the late Oligocene and has therefore great potential as a high-resolution archive. A detailed assessment of the preservation of the shell material by micro-X-ray fluorescence, X-ray diffraction, and electron backscatter diffraction reveals that it is pristine and not affected by diagenetic processes. Oxygen isotope analysis and microscopy indicate that the species had a longevity of up to a decade or more and, importantly, that it grew fast and large enough so that seasonally resolved records across multiple years were obtainable from it. Clumped isotope analysis revealed a mean annual temperature of 13.5 ± 3.8 ∘C. The subspecies likely experienced slower growth during winter and thus may not have recorded temperatures year-round. This reconstructed mean annual temperature is 3.5 ∘C warmer than the pre-industrial North Sea and in line with proxy and modelling data for this stratigraphic interval, further solidifying A. benedeni benedeni's use as a climate recorder. Our exploratory study thus reveals that Angulus benedeni benedeni fossils are indeed excellent climate archives, holding the potential to provide insight into the seasonality of several major climate events of the past ∼ 25 million years in northwestern Europe.
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RBINS Staff Publications 2023
Tropical rain forests are inhabited by a wide range of plant and animal diversity. However, little is known about the diversity of ant (Hymenoptera: Formicidae) species in these areas. To fill the gap, a study has been conducted in seven sites inside Nyungwe National Park, a tropical rain forest located in South-Western Rwanda. Data have been collected in October 2021 through a quick sampling using pitfall traps, arboreal traps, baiting, Winklers, and hand searching of nests in leaf litter, soil, rotten and fallen wood, and under stones. Collected ant specimens have been identified to subfamily, genus and species levels by using the identification keys. Names of species have been confirmed after comparing the findings with the specimens housed at the Royal Belgian Institute of Natural Science (Brussels, Belgium) and at Kiko Gomez’s personal collection (Barcelona, Spain). A total of 7 subfamilies, 28 genera and 74 species were sampled. The subfamily Myrmicicnae had more genera and species compared with other subfamilies. Further, 9 genera and 43 species were collected in Rwanda for the first time, while 13 species were potentially undescribed ant species. High number of species has been sampled in the sites located in secondary forest at Karamba (53 species) and Pindura (33 species). We recommend intensive sampling in other locations of Nyungwe tropical rainforest and in the rest of Rwanda mountain tropical rain forests to get a clear view on the diversity of ant species in Rwanda.
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RBINS Staff Publications 2022
