Search publications of the members of the Royal Belgian institute of natural Sciences
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New insights in the groundwater species diversity of the isopod genus Metastenasellus in Benin and Cameroon
- Among obligate groundwater organisms (stygobiontes), the Stenasellidae is a diverse family of isopods (Crustacea) that is mainly found in tropical Africa. However, our knowledge of the diversity and endemism of stygobiotic crustaceans found in Africa remains limited due to a lack of studies and a deficit in taxonomic expertise. Within the Stenasellidae, the genus Metastenasellus Magniez, 1966 is currently composed of nine species with a trans-Saharan distribution, but the recent descriptions of two new species in Cameroon suggest that its diversity is largely underestimated. Here, we further explore the diversity of Metastenasellus by sequencing the DNA barcode fragment of 57 Beninese and 27 Cameroonian specimens from 24 and 29 localities respectively. A data set of 84 new and 8 GenBank sequences was analysed with four species delimitation methods (ABGD, PTP, GMYC and KoT). All methods agreed on a minimum of 23 putative species, 11 from Benin and 12 from Cameroon. Ongoing morphological scrutiny of the male pleiopods of these putative species confirm that they correspond to distinct species. The coexistence of two putative species in some localities is further evidence that they represent separate evolutionary lineages. The geographical distribution of the 23 putative species suggests a restricted distribution and a low dispersal capacity of Metastenasellus species, as already observed for macrostygobionts in Europe. Given the number of potential species currently observed per sampled station, it is to be expected that many new species could be discovered by increasing the sampling effort. There also appears to be a decoupling between watersheds and species distribution, suggesting that watersheds are a rough approximation of water table boundaries or that the current distribution of Metastenasellus is more the result of historical factors than of dispersal constraints related to the current configuration of the catchment areas.
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Population genomics of introduced Nile tilapia Oreochromis niloticus (Linnaeus, 1758) in the Democratic Republic of the Congo: Repeated introductions since colonial times with multiple sources.
- During colonial times, Nile tilapia Oreochromis niloticus (Linnaeus, 1758) was introduced into non-native parts of the Congo Basin (Democratic Republic of the Congo, DRC) for the first time. Currently, it is the most farmed cichlid in the DRC, and is present throughout the Congo Basin. Although Nile tilapia has been reported as an invasive species, documentation of historical introductions into this basin and its consequences are scant. Here, we study the genetic consequences of these introductions by genotyping 213 Nile tilapia from native and introduced regions, focusing on the Congo Basin. Additionally, 48 specimensfrom 16 other tilapia species were included to test for hybridization. Using RAD sequencing (27,611 single nucleotide polymorphisms), we discovered genetic admixture with other tilapia species in several morphologically identified Nile tilapia from the Congo Basin, reflecting their ability to interbreed and the potential threat they pose to the genetic integrity of native tilapias. Nile tilapia populations from the Upper Congo and those from the Middle-Lower Congo are strongly differentiated. The former show genetic similarity to Nile tilapia from the White Nile, while specimens from the Benue Basin and Lake Kariba are similar to Nile tilapia from the Middle-Lower Congo, suggesting independent introductions using different sources. We conclude that the presence of Nile tilapia in the Congo Basin results from independent introductions, reflecting the dynamic aquaculture history, and that their introduction probably leads to genetic interactions with native tilapias, which could lower their fitness. We therefore urge avoiding further introductions of Nile tilapia in non-native regions and to use native tilapias in future aquaculture efforts.
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Tintigny: A Polymict Eucrite from Belgium
- In February 1971, a meteorite fell on the roof of a barn belonging to Mr. E. Schmitz in Tintigny, a village in southern Belgium. Upon its recovery, its meteoritic origin was confirmed by the schoolteacher, Mr. A. Rossignon who then looked after the sample. In 2017, for the first time, the meteorite was given to specialists for a detailed examina-tion and classification. We used various analytical techniques to characterize its mineralogy, elemental, and isotopic composition. Based on the obtained data, we classified it as a polymict eucrite, a meteorite originating from 4 Vesta, and named it Tintigny [1]. Tintigny is partly covered by shiny black fusion crust. Its interior mainly exhibits a light grey color and shows a brecciated texture composed of a fine-grained matrix, hosting darker crystals and cm-sized dark grey clasts. Under the microscope, a brecciated sub-ophitic basaltic texture mainly composed of plagioclase/maskelynite and clinopy-roxene is dominant. In addition to the dominant sub-ophitic texture, at least three distinct textures exposed in clasts are observable. At least two generations of shock effects (such as fractures), are present in the sample: those limited to clasts and large crystals, and those that crosscut both the large grains and the matrix. The accessory minerals include troilite, ilmenite, chromite, FeNi metal, and silica. Mineral chemistry calculations of pyroxene end-members show ranges from 8.5 to 60.7 mol% for enstatite, 30.1–70.0 mol% for ferrosilite, and 2.6–38.4 mol% for wollastonite. Based on these values, most pyroxenes in Tintigny are pigeonite and augite [2]. The Fe/Mn ratios of pyroxenes range from 27.1 to 39.3, with the highest ratio observed in pyroxene from the symplectitic clast. Fe/Mn and Fe/Mg ratios in low-Ca pyroxene (Wo<10) are 30.2±4.4 and 0.8±0.3, respectively. These ratios in high-Ca pyroxene (n=8) are 34.3±3.7 for Fe/Mn and 2.6±2.4 for Fe/Mg. The average pyroxene Fe/Mn ratio for all pyroxene is 32.5±4.4 (SD, n=14). Fe/Mg ranges from 0.6 to 8.2, with an average value of 1.8±2.0 (SD, n±14). Considering pyroxene Fe/Mn ranges of 40±11, 62±18, 32±6, and 30±2 for basaltic rocks from the Earth, Moon, Mars, and 4 Vesta (eucrites), respectively, and based on our data, particularly those of low-Ca py-roxene, Tintigny falls in the range of basaltic eucrites [3]. The bulk rock Fe/Mn and Fe/Mg ratios of Tintigny are 33.9 and 3.1, respectively. These values overlap with those measured for howardite-eucrite-diogenite (HED) and martian meteorites [4]. With a Ga/Al ratio of 4.17×10-5, Tintigny falls within the range of those of eucrites. Using the CI-normalized elemental concentration, we can see strong simi-larities between Tintigny and noncumulate eucrites, which is also reflected based on the abundance of TiO2 (0.63) and FeO/MgO ratio (2.66) in Tintigny. The bulk oxygen isotopic composition of Tintigny, as determined by laser fluorination, is also consistent with it being an HED (δ17O=1.72±0.04 ‰; δ18O=3.76±0.08‰; Δ17O=-0.25±0.01 ‰ (n=2, errors 2SD)), with a composition that plots close to the Eucrite Fractionation Line [5]. Based on the Meteoritical Bulletin Database, only 70 HED falls have been reported so far. Including Tintigny, only 39 eucrite falls are known to date, 11 of them occurred in Europe, with Tintigny being the only one from Belgium. In addition to the scientific importance of studying a eucrite fall like Tintigny, we emphasize the significance of the discovery of a historical meteorite fall by drawing attention to national scientific heritage that must be properly un-derstood and safeguarded for generations of scientists, scholars, and amateurs to come. Nowadays, together with four other meteorites from Belgium (Hautes Fagnes LL5, Lesves L6, St. Denis Westrem L6, and Tourinnes-la-Grosse L6), the Tintigny achondrite is exhibited in the meteorite gallery of the Institute of Nat-ural Sciences in Brussels and is open to the public for visits.
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FORENSIC CLASSIFICATION OF METEORITES: THE CASE OF AN ORIENTED SPECIMEN FROM THE BELGIAN ANTARCTIC METEORITE COLLECTION
- Introduction: The meteorite classification processes require a sequence of semi-destructive to destructive analyses to elucidate the internal texture and chemical composition of the sample. Several methods have been proposed for classifying meteorites using a non-destructive approach such as magnetic susceptibility [1] or 3D petrographic analysis [2]. Specimens with unique orientation forms such as cone or shield-shaped, are often prioritized for non-destructive classification due to their significant exhibition value and insight into the aerodynamics of extraterrestrial material during their atmospheric entrance [3,4]. In this study, we present a description employing non-destructive analysis to classify a newly found flattened shield-shaped Antarctic meteorite discovered during the Belgian meteorite reconnaissance expedition 2022-2023 in the Sør Rondane area, East Antarctica [5]. This approach promises to provide detailed internal structural and information on physical properties without compromising the integrity of the sample. Methods: We utilized the X-ray Computed Tomography (XCT) RX Solutions EasyTom150 device at the Institute of Natural Sciences (Brussels, Belgique) to analyze the sample with dimensions of 37.1 mm x 44.0 mm x 52.6 mm (Fig. 1). A copper filter of 0.4 mm was used. The sample was scanned at a voxel size of 58.2 μm using the large focal spot mode at 145 kV, 38 W and 260 μA. We employed the program 3D Slicer [6] to analyze the three-dimensional properties and calculate the physical parameters. Additionally, magnetic susceptibility measurements were conducted on the field using an SM30 instrument. Preliminary results: Various forms of deformation, notably radial extension features, were detected, likely indicative of shock experiences undergone by the sample before entering the Earth’s atmosphere, hence corroborating its extraterrestrial origin (Fig. 1). Preliminary magnetic susceptibility measurement on the field indicated a value typical of L chondrites (log χ ~ 4.7 [5]). The interior XCT slices reveal that the sample comprises a dense metallic phase with few non-metallic inclusions, primarily located on the face opposite to the entry direction (red arrow in Fig. 1b). The total volume measures 22.09 cm3, with a corresponding mass of 151.1 g, indicating a meteorite bulk density of 6.8 g cm-3 comparable to iron meteorites (bulk density between 7 and 8 g cm-3 [7]). This is at odds with the preliminary magnetic susceptibility measurement. Additional non-destructive analyzes will be needed, notably μ-XRF measurements to offer a better comprehension of the origin of the sample. This underlines the difficulty of classifying a sample in a non-destructive manner
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De loopkevers van Nederland en België (Carabidae).
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Do agricultural zones on Santa Cruz Island, Galapagos, host native and endemic arthropods?
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Secrets of de Selys Longchamps archives: one watercolour and two records of niniteenth century observations of the grasshopper species Psophus stridulus (Linnaeus, 1758) and Locusta migratoria (Linnaeus, 1758) in Belgium (Orthoptera; Acrididae)
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The harbour porpoise ( Phocoena phocoena ): Consequences of anthropogenic underwater sound on their ecological value
- Mainly due to anthropogenic activities, disturbance to the marine environment by underwater sound sources is an increasing problem in our seas and oceans. One of these activities, i.e. the construction of offshore wind farms, constitutes a relatively new and fast growing industry and potentially induces wide-ranging underwater sound disturbance. It is important to determine the effects on the marine environment and to manage negative impacts with proper mitigation measures, in order to achieve both a good environmental status and renewable energy development. The response of harbour porpoise to impulsive anthropogenic underwater sound is relatively well studied. This animal can thus be used as a highly relevant (due to their representative appearance and biological sensitivity) study object for studies on anthropogenic noise pollution (Wright, 2013). This study focused on the differences in regulatory regimes with regards to offshore wind farm construction in various North Sea countries and how this impacts both harbour porpoise populations and installation costs. The direct and indirect operational consequences of the different regulatory regimes related to underwater sound mitigation with piling activities on the environmental impact of a population of harbour porpoises, in countries around the Southern North Sea was quantified using the interim Population Consequences of Disturbance model (Harwood & King, 2014a, 2014b)
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Digital Animal Sound Archive: a collaborative repository for bio-acoustics
- The use of animal sounds is widespread but yields extensive and scattered individual collections. Making this data FAIR will lead to deeper knowledge. The overall objective of DASA is to set-up a robust data model and a user-friendly website enabling Belgian bio-acoustic workers to collect, archive and explore biological acoustic data. The starting point is bats, but the data model is kept open for any biological or mechanical sounds. We will build a digital archive that adds to RBINS' collections, serves as a reference collection of species and call types, offers a validated dataset for classifiers and will be a resource for meta-analyses.
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Protomedetera, a new genus from the Oriental and Australasian realms (Diptera, Dolichopodidae, Medeterinae)
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Description of a New Mangrove Hercostomus Loew (Diptera: Dolichopodidae: Dolichopodinae) from Bohol, Philippines
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Two new species of mangrove Dolichopodidae from Bohol Island in the Philippines (Insecta: Diptera) and a checklist of the Dolichopodidae of the Philippines
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New data on the marine genera Cymatopus Kertesz and Thambemyia Oldroyed (Insecta, Diptera, Dolichopodidae) from rocky shores in southern Thailand with the description of a new species
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Natuursteen in Limburgse monumenten
- 294 p.
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‘Fake widespread species’: a new mangrove Thinophilus Wahlberg from Bohol, Philippines (Diptera, Dolichopodidae) that is cryptic with a Singaporean species
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Investigating urban ant community (Hymenoptera; Formicidae) in port cities and in major towns along the border in Côte d'Ivoire: a rapid assessment to detect potential introduced invasive ant species.
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Use of Soil and Litter Ants (Hymenopera; Formicidae) as Biological Indicators of Soil Quality under different Land uses in Southern Rwanda.
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An annotated checklist of the leaf beetles (Coleoptera; Chrysomelidae) from El Salvador, with additions from the Bechyné collection in the Royal Belgian Institute of Natural Sciences.
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A database of threat statuses and life-history traits of Red List species in Flanders (Nothern Belgium).
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Use of ground dwelling arthropods as biological indicators of soil quality under conserved tree species, coffee and banana plantations in Rwanda.
