1,720,989 research outputs found
An endemic species flock of Candonidae Kaufmann, 1900 (Crustacea, Ostracoda) from wells in Benin (Africa), with the description of a new subfamily, a new genus and five new species
No full textBetween 2015 and 2022, over 200 wells were sampled in four catchment areas of Benin, using both Cvetkov plankton nets (funnel 200 mu m mesh size, 150 mu m below valve) and baited traps. As artificial wells serve as ecotones (interfaces between surface and groundwater ecosystems), the ostracod fauna is mostly represented by two families; Cyprididae (mainly epigeic) and Candonidae (hypogeic). Here, we describe a new subfamily of Candonidae from the wells in Benin, the Benincandoninae subfam. nov. Hot & egrave;kpo & Martens, represented by one genus, Benincandona gen. nov. Hot & egrave;kpo & Martens. We found 35 species belonging to this evolutionary radiation, of which we describe five new species: Benincandona martini gen. et spec. nov. Hot & egrave;kpo & Martens, B. ibikounlei gen. et spec. nov. Hot & egrave;kpo & Martens, B. sakitii gen. et spec. nov. Hot & egrave;kpo & Martens, B. cebios gen. et spec. nov. Hot & egrave;kpo & Martens and B. trapezoides gen. et spec. nov. Hot & egrave;kpo & Martens. The new subfamily and genus are characterised by a unique combination of characters, such as a seven-segmented antennula and a caudal ramus with a fully developed ramus, a single apical (anterior) claw and three short setae. Species within the genus can be distinguished by their carapace and hemipenis morphology, together with some limb characteristics. Whereas extensive subterranean candonid radiations have previously been reported from Europe, North and Central America and Northwest Australia (Pilbara), this is the first time such a vast radiation of subterranean candonids is reported from (West) Africa.The present research forms part of the projects supported by UHasselt through the “Bijzonder Onderzoeks Fonds” (Ref: BOF22BL07/R – 12889), which enabled SJH to conduct this joint PhD research between UHasselt (Belgium) and the University of Abomey-Calavi (Benin). e also acknowledge the lobal Minds program, which funded SJH’s predoctoral visit in 2021. The Belgian national Focal Point of TI (lobal Taxonomic Initiative), within
the framework of the CEBioS programme, funded this research work in Benin, including the first research stay of SJH at the RBINS and the provision of microscope equipment for work in Benin. e are grateful to Dr. Luc Janssens, Anne-Julie Rochette, and the CEBioS team for facilitating SJH’s stay in Belgium. Special thanks to Dr. Patrick Martin for his significant contributions to groundwater biodiversity research in Benin and his continuous support of the career of SJH. e acknowledge Laetitia Despontin and Julien Cillis (RBINS, Belgium) for providing technical assistance with the SEM work. Prof. Dr. Thierry Backeljau and Dr. Yves Samyn are thanked for their help with collections. Jeroen Venderickx and the RBINS Freshwater Biology team, part of the OD Nature directorat are thanked for logistical help and their much appreciated collegiality. SJH would also like to express gratitude to the authorities of the University of Abomey-Calavi (Benin) for facilitating various field trips and laboratory work in Benin, and to Prof. Moudachirou Ibikounlé for his continuous support. Many thanks also to Dr. Moïssou Lagnika, Dr. Darius Tossavi, and the UAC/Department of Zoology team, as well as to ahabou Yarsekou, the local authorities and people from the villages in the different localities where we conducted fieldwork
Evidence for a single population expansion event across 24,000 km: the case of the deep‑sea scavenging amphipod Abyssorchomene distinctus
No full textAnthropogenic activities such as mining pose a putative threat to deep-sea ecosystems and baseline studies of key indicator species are required to assess future loss of biodiversity. We examined population genetic structure, connectivity, cryptic diversity and phylogeography of the deep-sea scavenging amphipod, Abyssorchomene distinctus, using DNA sequence data (mitochondrial COI and nuclear 28S genes) from 373 specimens collected from six abyssal basins. We observed a striking absence of cryptic diversity, suggesting a single, widely distributed species in the Pacific and Indian Ocean. A single event of population expansion across distances up to 24,000 km is further supported by a main ancestral haplotype in the star-like shaped COI haplotype network, a skewed nucleotide mismatch distribution and deviations from evolutionary neutrality tests. In the Pacific, A. distinctus showed weak genetic population structure and low differentiation between the basins of the Clarion-Clipperton Zone and the DISCOL Experimental Area, suggesting a possible higher chance of recovery from deep-sea mining impacts. However, since our data indicate a single recent historic population expansion event, A. distinctus populations will likely be affected to unknown extents, as the exact drivers shaping distribution and dispersion of A. distinctus are still unclear.We would like to acknowledge funding by the Belgian Science and Policy Ofce (BELSPO) for both JPI-Oceans “Mining Impact” Projects (BR/15/MA/JPI-DEEPSEA1 and BR/15/MA/JPI-DEEPSEA2).
We would like to thank the crew of the Research Vessel “Sonne” for their support during sampling. The authors thank Henri Robert for assistance during the feld campaign and Cedric d’Udekem d’Acoz for taxonomic identifcations. We furthermore are grateful to Ms. Dorien Aerts for the provided guidance to Deborah W. E. Dupont in morphological verifcation and dissection as well as practical support during molecular work
Natural populations of the putative ancient asexual Darwinula stevensoni (Crustacea, Ostracoda) differ in their microbiomes
No full textAlthough ostracods are important components in aquatic ecosystems, little is known about their microbiomes. Here, we analyzed the microbiomes of the putative ancient asexual ostracod species, Darwinula stevensoni, in three natural populations from different freshwater habitats in the UK, Belgium, and Spain. We applied high-throughput amplicon sequencing approaches to analyze the V3-V4 part of the bacterial 16S rRNA region. We tested for host-specific microbiomes by comparing bacterial assemblages of ostracods with those of sediment and water samples from the same locations. Around 2,200 Amplicon Sequence Variants (ASVs) were identified from ostracod samples with universal primers and 1,700 ASVs with endosymbiotic-specific primers, illustrating a high microbiome diversity in D. stevensoni. Most bacterial taxa were unique to the microbiome of D. stevensoni as compared to other freshwater invertebrates and to non-marine ostracods. Alpha diversity of ostracod microbiomes did not differ significantly between the three populations, but PERMANOVA detected significant differences in bacterial compositions. Microbiomes varied highly among ostracod specimens from the same population. Possible factors shaping ostracod microbiomes could be latitude, food, age, and environmental variables. Preliminary functionality analyses showed that Darwinula-specific microbiomes contribute to lipid, carbohydrate, nucleotide, and amino acid metabolic processes and the synthesis of co-factors and vitamins.Belgian Federal Science Policy (Belspo) [BR/314/PI/LATTECO]
This research was funded by Belgian Federal Science Policy (Belspo BR/314/PI/LATTECO). We thank Tijs Vandenberghe and Bart Hellemans for technical support
Ecology of ostracods inhabiting groundwaters in Benin, West Africa, with potential use of stygobites as indicators of groundwater quality
No full textOstracods are a significant component of groundwater ecosystems, affected by both abiotic environmental factors and biotic interactions. This study investigates the factors influencing ostracod communities in groundwater from dug wells in several regions of Benin, West Africa, which experiences chronic anthropogenic disturbances such as nutrient enrichment from sewage and fertilizer infiltration. We evaluated the presence of ostracod species in 219 wells across seven catchment areas, examining 31 predictor variables, which include a variety of water quality parameters, hydrology as well as several well characteristics such as closure, usage and well construction type. The influence of these variables was analyzed using distance-based linear models and redundancy analysis. Our research identified 60 ostracod species, which we classified into two ecological groups: 1) 36 stygobitic species from the family Candonidae, representing an endemic evolutionary radiation, and 2) 24 non-stygobitic species, mostly from the family Cyprididae. Through our analysis, we identified several key factors influencing ostracod community structure, with consistent patterns observed at both species and genus levels. The primary predictors, aside from well descriptors, included water chemical and physical properties, such as electrical conductivity, pH, temperature, and bicarbonate concentration, along with NO2- concentration, a factor not previously demonstrated to be crucial for ostracod assemblages. Elevated nitrite levels in groundwater were found to significantly affect the distribution of stygobitic and non-stygobitic ostracods. Stygobites were notably less frequent in environments with higher NO2- concentrations, likely due to their greater vulnerability to periodic or chronic anthropogenic disturbances compared to non-stygobites. Therefore, we suggest that stygobiticostracod species, identifiable even at the genus level, have a potential as reliable indicators of groundwater quality in the tropical regions of western Africa
New species of groundwater Candonidae (Crustacea, Ostracoda) from Benin: towards their use as bioindicators of water quality
No full textAquatic ecosystems are currently being subjected to major transformations as a result of anthropogenic actions and the effects of climate change, with a significant impact on public health by increasing the prevalence of water-borne diseases in Africa. Monitoring of groundwater quality is therefore becoming crucial to ensure clean drinking water supplies and preserving local ecosystems. Ostracods are small and bivalved aquatic crustaceans and due to their sensitivity to environmental variations, they are considered to be reliable bioindicators, although an accurate understanding of their ecology and distribution is required. Between 2015 and 2022, ostracods were sampled from more than 200 wells distributed over four catchment areas in Benin to explore the potential of ostracods as bioindicators. Sixty species of ostracods were identified and divided into two distinct ecological groups: 36 new to science stygobitic species from the family Candonidae, marking an endemic evolutionary radiation, and 24 non-stygobitic species, mainly from the family Cyprididae. Five new species of Candonidae were described, belonging to a new genus and subfamily, characterised by distinctive features such as a sevensegmented antennule, a specific caudal ramus, and other features of carapace and hemipenis morphology. Presence of ostracods was studied as a function of predictor variables, including water quality variables and other characteristics of the wells. The results showed that factors such as electrical conductivity, pH, temperature, bicarbonate concentration and NO2- levels significantly influenced the structure of ostracod communities. Stygobitic species compared to non-stygobites were found to be particularly sensitive to high nitrite levels, highlighting their vulnerability to anthropogenic disturbance. Thus, we conclude that the new stygobitic ostracod species, show promising potential to serve as reliable bioindicators for groundwater quality in tropical West Africa.
Keywords: Freshwater Ostracoda, Africa, water quality, ecology, bioindicator
Ecology of ostracods inhabiting groundwaters in Benin, West Africa, with potential use of stygobites as indicators of groundwater quality
No full textOstracods are a significant component of groundwater ecosystems, affected by both abiotic environmental factors and biotic interactions. This study investigates the factors influencing ostracod communities in groundwater from dug wells in several regions of Benin, West Africa, which experiences chronic anthropogenic disturbances such as nutrient enrichment from sewage and fertilizer infiltration. We evaluated the presence of ostracod species in 219 wells across seven catchment areas, examining 31 predictor variables, which include a variety of water quality parameters, hydrology as well as several well characteristics such as closure, usage and well construction type. The influence of these variables was analyzed using distance-based linear models and redundancy analysis. Our research identified 60 ostracod species, which we classified into two ecological groups: 1) 36 stygobitic species from the family Candonidae, representing an endemic evolutionary radiation, and 2) 24 non-stygobitic species, mostly from the family Cyprididae. Through our analysis, we identified several key factors influencing ostracod community structure, with consistent patterns observed at both species and genus levels. The primary predictors, aside from well descriptors, included water chemical and physical properties, such as electrical conductivity, pH, temperature, and bicarbonate concentration, along with NO2- concentration, a factor not previously demonstrated to be crucial for ostracod assemblages. Elevated nitrite levels in groundwater were found to significantly affect the distribution of stygobitic and non-stygobitic ostracods. Stygobites were notably less frequent in environments with higher NO2- concentrations, likely due to their greater vulnerability to periodic or chronic anthropogenic disturbances compared to non-stygobites. Therefore, we suggest that stygobiticostracod species, identifiable even at the genus level, have a potential as reliable indicators of groundwater quality in the tropical regions of western Africa
Distribution of freshwater ostracoda (Crustacea) collected from wells of Benin: a preliminary study
No full textContext: Ostracods are small bivalved crustaceans that abound in almost all water bodies, marine and non-marine (including estuarine), surface waters both permanent and temporary and groundwater. They can be used as environmental tracers in several research domains through their response to different environmental conditions and anthropogenic impacts. Objective: The present research aims to study the distribution of freshwater ostracods from wells across the catchment areas of Benin. Material and methods: From 2015 to 2021, nearly 200 wells were sampled in four catchment areas using two sampling methods: the use of a phreatobiological net (100-150 µm) and the installation of baited traps. Sorted from all samples in the laboratory using a binocular microscope, ostracods were identified using existing literature. Identification of some taxa required complete dissections with valve morphology illustrated by scanning electron microscopy and limbs drawn under a microscope equipped with a lucid camera. Results: Thanks to the ecotone aspect of the sampled wells, the ostracod species are represented by two families: the Cyprididae collected in 70% of the sampled stations on the one hand and the Candonidae in 11% on the other. The Cyprididae, with about fifteen species, belong to several different biogeographic categories: circumtropical, afrotropical and endemic to West Africa and represent all surface dwelling and mostly well-described taxa. Despite the relative rarity of groundwater-dwelling Candonidae, they represented by more than twenty-five potentially new species. This reveals an exceptional diversity with a very high rate of endemism: each well harbors its own species and some wells contain up to three distinct species. This is the first time such a vast radiation of subterranean ostracods is reported from (West) Africa.
Keywords: Distribution, ostracods, wells, biogeographic categories, endemism
Distribution of freshwater ostracoda (Crustacea) collected from wells of Benin: a preliminary study
No full textContext: Ostracods are small bivalved crustaceans that abound in almost all water bodies, marine and non-marine (including estuarine), surface waters both permanent and temporary and groundwater. They can be used as environmental tracers in several research domains through their response to different environmental conditions and anthropogenic impacts. Objective: The present research aims to study the distribution of freshwater ostracods from wells across the catchment areas of Benin. Material and methods: From 2015 to 2021, nearly 200 wells were sampled in four catchment areas using two sampling methods: the use of a phreatobiological net (100-150 µm) and the installation of baited traps. Sorted from all samples in the laboratory using a binocular microscope, ostracods were identified using existing literature. Identification of some taxa required complete dissections with valve morphology illustrated by scanning electron microscopy and limbs drawn under a microscope equipped with a lucid camera. Results: Thanks to the ecotone aspect of the sampled wells, the ostracod species are represented by two families: the Cyprididae collected in 70% of the sampled stations on the one hand and the Candonidae in 11% on the other. The Cyprididae, with about fifteen species, belong to several different biogeographic categories: circumtropical, afrotropical and endemic to West Africa and represent all surface dwelling and mostly well-described taxa. Despite the relative rarity of groundwater-dwelling Candonidae, they represented by more than twenty-five potentially new species. This reveals an exceptional diversity with a very high rate of endemism: each well harbors its own species and some wells contain up to three distinct species. This is the first time such a vast radiation of subterranean ostracods is reported from (West) Africa.
Keywords: Distribution, ostracods, wells, biogeographic categories, endemism
New species of groundwater Candonidae (Crustacea, Ostracoda) from Benin: towards their use as bioindicators of water quality
No full textAquatic ecosystems are currently being subjected to major transformations as a result of anthropogenic actions and the effects of climate change, with a significant impact on public health by increasing the prevalence of water-borne diseases in Africa. Monitoring of groundwater quality is therefore becoming crucial to ensure clean drinking water supplies and preserving local ecosystems. Ostracods are small and bivalved aquatic crustaceans and due to their sensitivity to environmental variations, they are considered to be reliable bioindicators, although an accurate understanding of their ecology and distribution is required. Between 2015 and 2022, ostracods were sampled from more than 200 wells distributed over four catchment areas in Benin to explore the potential of ostracods as bioindicators. Sixty species of ostracods were identified and divided into two distinct ecological groups: 36 new to science stygobitic species from the family Candonidae, marking an endemic evolutionary radiation, and 24 non-stygobitic species, mainly from the family Cyprididae. Five new species of Candonidae were described, belonging to a new genus and subfamily, characterised by distinctive features such as a sevensegmented antennule, a specific caudal ramus, and other features of carapace and hemipenis morphology. Presence of ostracods was studied as a function of predictor variables, including water quality variables and other characteristics of the wells. The results showed that factors such as electrical conductivity, pH, temperature, bicarbonate concentration and NO2- levels significantly influenced the structure of ostracod communities. Stygobitic species compared to non-stygobites were found to be particularly sensitive to high nitrite levels, highlighting their vulnerability to anthropogenic disturbance. Thus, we conclude that the new stygobitic ostracod species, show promising potential to serve as reliable bioindicators for groundwater quality in tropical West Africa.
Keywords: Freshwater Ostracoda, Africa, water quality, ecology, bioindicator
Stygobitic Candonidae (Crustacea, Ostracoda) Are Potential Environmental Indicators of Groundwater Quality in Tropical West Africa
No full textOstracods are important components of groundwater communities that are influenced by abiotic environmental conditions and biotic interactions. We aimed to identify the factors associated with ostracod assemblages inhabiting groundwaters accessed through dug wells in several regions of Benin in West Africa, exposed to chronic influences of anthropogenic disturbances such as nutrient enrichment from infiltration of sewage or fertilisers from the surface. Ostracods were collected from 219 wells in seven catchment areas using two complementary methods: active sampling with a phreatobiological net and passive trapping with a baited trap. Associations with 31 statistical predictor variables (a range of abiotic descriptors of water, hydrology, protection, usage and the type of well) and ostracod occurrence was evaluated using distance-based linear models and redundancy analysis. We identified 60 ostracod species representing two ecological groups: 36 species of stygobites of the family Candonidae, an endemic species flock of a vast evolutionary radiation, and 24 species of non-stygobites, mostly of the family Cyprididae. This is the first large groundwater ostracod species flock reported from the entire African continent. A number of variables associated with the structure of ostracod assemblages were identified. Except for the descriptors of wells, these included well-known chemical and physical properties (electrical conductivity, pH, temperature or bicarbonate concentration), but also the concentration of NO2-. Although NO2- has not yet been demonstrated to be important for ostracod assemblages, stygobites occurred significantly less frequently in higher concentrations of NO2- than most non-stygobites. We determined that stygobitic (candonid) ostracod species and genera may be a good potential environmental indicator of groundwater quality especially nitrite pollution of groundwater in tropical West Africa. In tropical West Africa, many human populations rely on groundwater for domestic use and agricultural irrigation, while these aquatic resources are also often affected by anthropogenic disturbances. The use of stygobitic ostracods as potential indicators of groundwater quality offers a valuable tool for environmental monitoring and protection in tropical regions in West Africa, and may be also globally.Funding:
This study was supported by Global Taxonomy Initiative, Programme “Capacities for Biodiversity and Sustainable Development” (CEBioS),Hasselt University and Université d'Abomey- Calavi.
This work was supported by the Belgian national Focal Point of GTI (Global Taxonomy Initiative), through various Programme “Capacities for Biodiversity and Sustainable Development” (CEBioS) GTI Projects (Refs.: 2459LJB2_SO1-SBES-2.1_Martin_2015; 2459LJB2 SO1-SBES-2.1_ Martin_2016; 2459LJB2_SO1-SBES-2.1_Martin_2017; 2018/SO1-
SBES-2.1/183; 1.1-2/2019/008; R1.1-2/2020/072; Ref.: R.1.1-2/2022/137) for fieldwork in Benin. These projects also funded the first research stay of SJH at the RBINS and the provision of microscope equipment for work in Benin. Hasselt University (UHasselt) supported the work of SJH through the “Bijzonder Onderzoeks Fonds” (Ref: BOF22BL07/R—12889) and the Global Minds program and attributed the Special Research Fund (BOF24kV06) to a research visit of TN, which facilitated SJH's joint PhD research conducted at the UHasselt (Belgium) and the Université d'Abomey - Calavi (Benin). We also thank the Ministry of Higher Education and Scientific Research of Benin for their support via the “Appui aux Doctorant” Program and the Laboratory of Water Analysis at the Regional Water Service of Borgou, where physical and chemical analyses of water samples were conducted. We are particularly grateful to Dr. Luc Janssens, Anne-Julie Rochette, and the CEBioS team for their support, to Dr. Yves Samyn for his help with collections, to Jeroen Venderickx and the RBINS Freshwater Biology team for logistical help, to Mr. Jean-Pierre Montcho, Mr. Farouk Mazou to the authorities of the Université d'Abomey-Calavi
(Benin) for facilitating various field trips and laboratory work in Benin, to Dr. Darius Tossavi, Dr. Onzo and the UAC/Department of Zoology team, as well as to Mr. Wahabou Yarsekou, Mr. Orou Goura Doussi, the local authorities and people from the villages in the different localities where we conducted fieldwork. We thank two anonymous referees for their important input
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