The new geological map of Wallonia permits to obtain a more global view of the tectonic organization of the Palaeozoic terrains around the Variscan Front in southern Belgium. This zone oriented WSW-ENE and passing south of an axis Charleroi-Namur, was firstly highlighted by the coal mining works, but has been significantly documented notably through deep boreholes and seismic profiles. A coherent structural sketch of the Variscan Front is proposed for its entire longitudinal course, where the following structural units are distinguished, from north to south: the Brabant Massif and the base of the cover unaffected by the Variscan orogeny, the Brabant Parautochthon, the Haine-Sambre-Meuse Overturned Thrust sheets (HSM-OTS) and the Ardenne Allochthon. Undeformed terrains during Variscan event constitute the northern border of the Variscan Front. The Brabant Parautochthon includes Devono-Carboniferous terrains, which are folded and faulted. The HSM-OTS are formed by the superposition of several sheets (e.g. La Tombe sheet), which are supported by various thrust faults (e.g. Masse fault). The Ardenne Allochthon, which has been displaced during the Variscan orogeny, rests on the Brabant Parautochthon and the HSM-OTS through a faulted zone, which is locally known as the Midi Fault.
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With 53 formally described species, the genus Cypretta is one of the most common freshwater ostracod genera in the world. It has a mainly circumtropical distribution. The type species, Cypretta tenuicauda (Vávra, 1895), was described from Zanzibar (Africa) in a superficial way. Therefore, the morphology and identity of this species and of the genus remained problematic until today. Here, we redescribe Cypretta tenuicauda from the original type material and discuss the morphology of the species and the diagnosis of the genus. The species is characterized by the presence of anterior marginal septa in both valves, the sub-triangular carapace shape in lateral view, the right valve overlapping the left valve, the generally wide carapace and the presence of a serrated posteroventral inner list in the right valve. In addition, both α and β setae on the mandibular palp are long and thin, claws Ga and Gp on the caudal ramus are elongated and seta-like, while the caudal ramus itself is equally slender. The caudal ramus attachment is reduced to a simple branch. The present redescription of the type species will assist in creating order in what is now a taxonomically confused genus.
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RBINS Staff Publications 2023
