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Pristina (Pristinella) sp. No. 1 (A,B,D), Pristina (Pristinella) sp. No. 2 (C,E–G) and Pristina (Pristinella) sp. No. 3 (H–N) from Vietnam. (A): entire body, lateral view; (B): dorsal bundle of chaetae; (C,H): anterior part of the body, lateral view; (D,E,I): simple-pointed needle chaetae; (F): bifid needle chaeta; (G,K,L): tips of bifid needle chaetae; (J): tip of simple-pointed needle chaeta; (M,N): tips of trifid needle chaetae.
Source publication
This work continues a series of publications on the diversity of the main groups of invertebrates found through the investigation of meiobenthic communities in various inland waterbodies in central and southern Vietnam. Here, a checklist of oligochaetes and aeolosomatids (the annelid worms) discovered for the period 2010–2021 is presented, as well...
Citations
... The basin area is 0.6 km 2 , but it often varies seasonally (wet or dry season) due to flow-through dam operations. The average depth of the reservoir is 1.5 m, with a maximum depth of 9 m, and the bottom sediment type is gray clay with a thin layer of silt (Gusakov et al. 2023). The wide littoral zone, comprising sand and silt soils, covers 10% of the basin area. ...
... This distribution pattern may be related to food availability, which decreases with distance from the river flow and possibly with increasing water depth (deeper locations No. 7-9). The quantity and occurrence of benthic invertebrates in the deep zones of Vietnamese reservoirs are low (Gusakov et al. 2023), which likely influences the distribution of benthic fish in the Suoi Trau reservoir. Our findings align with earlier data indicating that fish in Vietnamese reservoirs often occur in shallow water near the banks (Stolbunov 2014). ...
Several non-native fish successfully occupy many water systems in Vietnam, including reservoirs. The aim of our study was to identify non-native and native fish species in the Suoi Trau reservoir and to estimate their distribution during the dry season. Gill nets and sectional net traps were used at multiple locations of the reservoir to capture and identify fish during the year 2019-2020. To assess the distribution and abundance of fish in the Suoi Trau we maintained numerous gill nets near bottom and near surface across the reservoir from April to May 2024. Thirty-four native species and three non-native species were identified: the African catfish Clarias gariepinus (first recorded in the reservoir), Nile tilapia Oreochromis niloticus, and loricariids Pterygoplichthys spp. In 2024, were captured only eleven native fish species, as well as non-native Nile tilapia and armoured catfish. We observed that loricariids frequently occupied areas in the reservoir along with native fish, and their numbers positively correlated with the numbers of native fish. However, the high occurrence of Nile tilapia did not correspond with a high occurrence of native fish in the reservoir. The total biomass of the two non-native species constituted 19% of the total biomass of all captured native fish in Suoi Trau reservoir, and the biomass of armoured catfish highly dominated in four of the nine sampled locations. The loricariids are gradually could replace the native ichthyofauna in the reservoir.
... This straightening continued through the segmental region and zooid region, where similar contractions occurred before all body regions returned to their original shape. Gusakov et al. (2023) reported that the family Aeolosomatidae employs wriggling movements for swimming. The worm was able to bend itself to an external bending diameter of approximately 0.2 mm. ...
Background
Protists and helminths are considered the main organisms invading different cultures, especially aquatic organisms. Morphometric characteristics remain the most trustworthy descriptors of species identification or, more broadly, pattern recognition.
Aim
This study aimed to provide morphological descriptions of the most prevalent Protista and helminths found in various street wetlands in Port Said, Egypt.
Methods
This study collected three water samples per area each month. The samples were sent to the Parasitology Laboratory at Port Said University, Egypt. The samples were analyzed in two ways according to organism size. Large helminths were observed within 24 hours using a microscope, and their movements were recorded. Protists and helminth eggs were isolated by filtering water through a 0.45 μm cellulose acetate filter, followed by centrifugation. The isolated organisms were counted and imaged.
Results
Nine dominant organisms were identified in the collected samples, including five parasitic species (Protoopalina sp., Balantidium coli, Entamoeba sp., Fasciola sp., and Haemonchus sp.) and four free-living species (Paramecium sp., Euplotes sp., Echiniscus sp., and Aeolosoma sp.). Protoopalina sp. was the most abundant parasite (17.6%), exhibiting a cylindrical, elongated shape (97.3–139 µm in length, 30–48 µm in width). Euplotes sp. were the free-living organisms (17%), measuring 59.7–66.5 µm in length and 32.1–42.5 µm in width, featuring cirri and dark bristles. Paramecium sp., with lengths between 161 and 256 µm, was spindle-shaped and had visible contractile vacuoles. B. coli trophozoites measured 60–107 µm in length and 46.5–83.3 µm in width, with a large posterior macronucleus. Haemonchus sp. larvae were about 700 µm long, with a distinct tail filament assisting their complex movement.
Conclusion
The street wetlands in the surveyed area contain various free-living and pathogenic taxa. There is a need to link the presence of these organisms to physicochemical analyses. Future studies should prioritize broader geographic sampling, the integration of molecular techniques, and the exploration of host-parasite relationships.
... This straightening continued through the segmental region and zooid region, where similar contractions occurred before all body regions returned to their original shape. Gusakov et al. (2023) reported that the family Aeolosomatidae employs wriggling movements for swimming. The worm was able to bend itself to an external bending diameter of approximately 0.2 mm. ...
Background: Protists and helminths are considered the main organisms invading different cultures, especially aquatic organisms. Morphometric characteristics remain the most trustworthy descriptors of species identification or, more broadly, pattern recognition. Aim: This study aimed to provide morphological descriptions of the most prevalent Protista and helminths found in various street wetlands in Port Said, Egypt. Methods: This study collected three water samples per area each month. The samples were sent to the Parasitology Laboratory at Port Said University, Egypt. The samples were analyzed in two ways according to organism size. Large helminths were observed within 24 h using a microscope, and their movements were recorded. Protists and helminth eggs were isolated by filtering water through a 0.45 μm cellulose acetate filter, followed by centrifugation. The isolated organisms were counted and imaged. Results: Nine dominant organisms were identified in the collected samples, including five parasitic species (Protoopalina sp., Balantidium coli, Entamoeba sp., Fasciola sp., and Haemonchus sp.) and four free-living species (Paramecium sp., Euplotes sp., Echiniscus sp., and Aeolosoma sp.). Protoopalina sp. was the most abundant parasite (17.5%), exhibiting a cylindrical, elongated shape (97.3–139µm in length, 30–48µm in width). Euplotes sp. were the free-living organisms (17%), measuring 59.7–66.5 µm in length and 32.1–42.5µm in width, featuring cirri and dark bristles. Paramecium sp., with lengths between 161 and 256 µm, was spindle-shaped and had visible contractile vacuoles. B. coli trophozoites measured 60–107µm in length and 46.5–83.3µm in width, with a large posterior macronucleus. Haemonchus sp. larvae were about 700 µm long, with a distinct tail filament assisting their complex movement. Conclusion: The street wetlands in the surveyed area contain various free-living and pathogenic taxa. There is a need to link the presence of these organisms to physicochemical analyses. Future studies should prioritize broader geographic sampling, the integration of molecular techniques, and the exploration of host-parasite relationships.
This work is the third installment in a series of publications devoted to the diversity, distribution and ecology of major groups of hydrobionts discovered during the study of meiobenthic communities in inland waters of central and southern Vietnam. Here, a checklist of cladoceran crustaceans (Cladocera) found for the period 2010–2022 is presented, as well as generalized and updated data on their taxonomy, ecology and global/local distribution, based on the latest studies. A total of 55 representatives from four families (Sididae, Ilyocryptidae, Macrothricidae and Chydoridae) and 29 genera are recorded. Of these, 13 taxa were detected in Vietnamese water bodies for the first time, including the chydorid Paralona pigra, which was the first registered in the Oriental region as a whole. Another four discovered forms from the genera Ilyocryptus, Macrothrix, Prendalona and Ephemeroporus require additional research. They may belong to not-yet-described species because they exhibit noticeable morphological differences from other known relatives. Based on newly obtained and previously published data, the diversity of Cladocera from the bottom and near-bottom ecological groups in Vietnam today can be estimated at around 95 representatives (four Sididae, seven Ilyocryptidae, one Ophryoxidae, nine Macrothricidae and 74 Chydoridae). A review of the available literature, together with the significant proportion of new and still poorly studied taxa found in our material, indicate the need for further comprehensive studies on the cladocerans in the region.
