Search publications of the members of the Royal Belgian institute of natural Sciences
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Fifteen species in one: deciphering the Brachionus plicatilis species complex (Rotifera, Monogononta) through DNA taxonomy
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The influence of environmental variables on freshwater rotifers of the family Brachionidae and Lecanidae in Thailand
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Deep-water parasite diversity in Lake Tanganyika: description of two new monogenean species from benthopelagic cichlid fishes
- Background: Lake Tanganyika is the world’s second deepest lake. Its diverse cichlid assemblage offers a unique opportunity for studying a deep-water host-parasite model in freshwater. Low host specificity and a broad host range including representatives of the Bathybatini tribe in the only monogenean parasite described from this habitat, Cichlidogyrus casuarinus Pariselle, Muterezi Bukinga & Vanhove, 2015 suggest a link between lower specificity and lower host density. Conversely, high host specificity and species richness are reported for monogeneans of the lake’s littoral cichlids. We further investigated whether the deep-water environment in Lake Tanganyika is really monogenean species-depauperate by investigating the monogenean fauna of Trematocara unimaculatum (a representative of the tribe Trematocarini, the sister lineage of the Bathybatini) and Benthochromis horii, a member of the tribe Benthochromini, found in the same deep-water habitat as the already known hosts of C. casuarinus. Methods: Sclerotised structures of the collected monogenean individuals were characterised morphologically using light microscopy and morphometrics. Results: Both examined cichlid species are infected by a single monogenean species each, which are new to science. They are described as Cichlidogyrus brunnensis n. sp., infecting T. unimaculatum, and Cichlidogyrus attenboroughi n. sp., parasitising on B. horii. Diagnostic characteristics include the distal bifurcation of the accessory piece in C. brunnensis n. sp. and the combination of long auricles and no heel in C. attenboroughi n. sp. In addition C. brunnensis n. sp. does not resemble C. casuarinus, the only species of Cichlidogyrus thus far reported from the Bathybatini. Also Cichlidogyrus attenboroughi n. sp. does not resemble any of the monogenean species documented from the pelagic zone of the lake and is among the few described species of Cichlidogyrus without heel. Conclusions: As two new and non-resembling Cichlidogyrus species are described from T. unimaculatum and B. horii, colonisation of the deep-water habitat by more than one morphotype of Cichlidogyrus is evident. Based on morphological comparisons with previously described monogenean species, parasite transfers with the littoral zone are possible. Therefore, parasites of pelagic cichlids in the lake do not seem to only mirror host phylogeny and the evolutionary history of this host-parasite system merits further attention.
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The Genus Chaetogaster Baer, 1827 (Annelida, Clitellata) in Switzerland: A First Step toward Cataloguing Its Molecular Diversity and Description of New Species on a DNA Sequence Basis
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Coastal geoarchaeology in the Mediterranean – on the interdependence of landscape dynamics, harbour installations and economic prosperity in the littoral realm, Panel 2.3. Archaeology and Economy in the Ancient World
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High-resolution facies analysis of a coastal sabkha in the eastern Gulf of Salwa (Qatar): A spatio-temporal reconstruction.
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Physiogeographische Geländepraktika in Zeiten der COVID-19-Pandemie.
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The unexpectedly short Holocene Humid Period in Northern Arabia.
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A comprehensive review on structural tsunami countermeasures.
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Insights into Holocene relative sea-level changes in the southern North Sea using an improved microfauna-based transfer function.
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Coastal geoarchaeology in the Mediterranean – on the interdependence of landscape dynamics, harbour installations and economic prosperity in the littoral realm, Panel 2.3. Archaeology and Economy in the Ancient World – Proceedings of the 19th Internationa
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Holocene climatic changes of the northern Arabian Peninsula and their implications for Neolithic incursions and the “oasisation” process
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ISROC—Inundation Signatures on ROcky Coastlines—A new Research Coordination Network targeting coastal boulder deposits
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The unexpectedly short Holocene Humid Period in Northern Arabia
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Development of seafloor mapping strategies supporting integrated marine management: application of seafloor backscatter by multibeam echosounders.
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Redescription of the type species of the genus Cypretta (Ostracoda, Crustacea), with notes on the taxonomy of the genus
- 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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Predicted changes in the distribution of Ostracoda (Crustacea) from river basins in the southern cone of South America, under two climate change scenarios
- While many studies predict changes in the distribution of individual species as a result of climate change, few studies have assessed such changes at the community level for aquatic invertebrates. We used ostracods (bivalved micro-crustaceans) to assess the effects of climate change on regional species richness, (re-) distribution and community composition across the river basins of the Southern Cone of South America. Using a range of niche-based models, we present projections of changes in diversity components in the light of two scenarios on increased carbon emissions: the moderate-optimistic (RCP 4.5) and the pessimistic (RCP 8.5) scenarios from four climate models on 2050 and 2080 scenarios. Future projections show increase in the number of (mapped) cells with a richness up to five species as compared to present-day situations. La Plata basin (LPLA) presents the highest species loss, mainly in the Paraguay and Paraná rivers, while the species gain occurred mainly in the La Puna Region, North Chile-Pacific Coast and southern LPLA basins. Global change might impact ostracod communities even on a medium term (2050). Despite losses of local species in all future scenarios, a small portion of the LPLA was identified as a potential future climatic refugia for ostracod communities, while the distribution area in Patagonia was predicted to be extremely small for some ostracods at the southernmost parts of South Argentina-South Atlantic Coast and South Chile-Pacific Coast basins in both futures. These results indicate that non-model organisms can also contribute greatly to formulate evidence-based management plans for aquatic ecosystems under climate change scenarios.
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Seven new species and two new genera of Physocypria sensu latu (Crustacea, Ostracoda) from Brazilian floodplains
- We describe seven new species in two new genera of the Physocypria sensu latu clade (Cyclocypridinae) from three of the main Brazilian floodplains. Brasilocypria pea gen. et spec. nov. and Brasilocypria ricardopintoi gen. et spec. nov. occur in the Upper Paraná River floodplain and the South Matogrossense Pantanal, Claudecypria mesquitai gen. et spec. nov., Brasilocypria alisonae gen. et spec. nov. and Claudecypria rochei gen. et spec. nov. were found in the South Matogrossense Pantanal, and Brasilocypria lordi gen. et spec. nov. and Brasilocypria namiotkoi gen. et spec. nov. occur in the Amazon River floodplain. All new species here described were found as sexual populations. Generally, they have a short and suboval carapace, with the left valve overlapping the right valve on all sides, except for the dorsal side in some species. The morphology of the hemipenis and the prehensile palps, together with the shape of the valves, were the most important characters to distinguish the species. Size differences between species can be substantial. Several characters, such as the absence in all new species of the short accompanying seta of the five natatory setae on the antenna; the presence in all new species of a long seta next to the two a-setae on the first thoracopod, and the presence/absence or differences in length of specific setae on the second and third thoracopod, are relevant for the generic diagnoses. We also redefine Keysercypria Karanovic, 2011.
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A moderate differential effect of organic and conventional agriculture across taxonomic groups inhabiting farmland ponds
- 1. Organic agriculture is increasingly promoted as a more environmentally friendly alternative to conventional agriculture, as it restricts the use of fertilisers and synthetic pesticides. However, the impact of both farming systems on aquatic biodiversity is strongly debated. Ponds are abundant in agricultural landscapes and strongly contribute to biodiversity. They also respond strongly to land use on a very local scale. The present study assessed the effects of conventional and organic agriculture on the taxonomic diversity of multiple groups of aquatic organisms at local and regional spatial scales. 2. We conducted a broad scale field survey to quantify the differential impact of conventional and organic agriculture on local environmental conditions in ponds, on community composition and on local, among site and regional diversity of macrophytes, cladoceran zooplankton and selected macroinvertebrates in Belgian farmland ponds (Flanders). 3. We observed that organic agriculture was moderately positively associated with higher local species richness for shoreline vegetation, but not for other organism groups. Only minor differences were observed for among-pond variation, and these were mostly related to rare species of cladocerans and heteropterans. At the regional scale, ponds in organic showed higher species richness than in conventional farmland for shoreline vegetation, emergent vegetation, and cladoceran zooplankton, but lower for coleopterans and gastropods. There was no significant effect of agricultural type on water quality. 4. We conclude that organic farming is associated with moderate positive effects on pond biodiversity and regional species richness of plants and zooplankton. We observed no systematic differences between the two types of agriculture in local environmental conditions in ponds. The absence of large differences in biodiversity and water quality between ponds located in organic and conventional farmland might be related to the dominance of intensive conventional farming in our study region and the history of conventional farming around ponds that are now surrounded by organic farming. Future studies should include other factors such as the structure of the landscape and the role of natural elements such as buffer strips surrounding the ponds.
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The gravity database for Belgium