It is widely accepted among the Cladocera (Crustacea) taxonomists that almost all cosmopolitan taxa are represented by some un-revised complexes of cryptic species. But many macro taxa of the cladocerans are still unrevised. The aim of this work is to analyze the taxonomic status of Oriental populations of the genus Bosminopsis Richard, 1895 (Anomopoda: Bosminidae) based on morphological characters. We have studied populations from India, Myanmar, Cambodia, Thailand, Laos, Vietnam, Philippines, Malaysia and Papua New Guinea and concluded that Oriental populations belong to a single species, Bosminopsis africanus (Daday, 1908), initially described from Africa. Analysis of literature data confirms that is widely distributed through whole Oriental zone. A single large mucro, or the mucro accompanied by an additional small spine in both sexes, is the main trait which differentiates B. africanus from B. zernowi Linko, 1901 distributed in more northern regions of Eurasia.
Per- and polyfluoroalkyl substances (PFAS) are gaining worldwide attention because of their toxicity, bioaccumulative and resistance to biological degradation in the environment. PFAS can be categorised into endocrine disrupting chemicals (EDCs) and identified as possible carcinogenic agents for the aquatic ecosystem and humans. Despite this, only a few studies have been conducted on the aquatic toxicity of PFAS, particularly in invertebrate species such as zooplankton. This study evaluated the acute toxicity of two main PFAS, perfluorooctanoic acid (PFOA) and perfluorooctanesulfonate (PFOS), by using freshwater cladocerans (Moina micrura) as bioindicators. This study aimed to assess the adverse effects at different levels of organisations such as organ (heart size and heart rate), individual (individual size and mortality) and population (lethal concentration, LC50). PFOA was shown to be more hazardous than PFOS, with the LC50 values (confidence interval) of 474.7 (350.4-644.5) μg L-1 and 549.6 (407.2-743.9) μg L-1, respectively. As the concentrations of PFOS and PFOA increased, there were declines in individual size and heart rate as compared to the control group. The values of PNECs acquired by using the AF method (PNECAF) for PFOA and PFOS were 0.4747 and 0.5496 μg L-1, respectively. Meanwhile, the PNEC values obtained using the SSD method (PNECSSD) were 1077.0 μg L-1 (PFOA) and 172.5 μg L-1 (PFOS). PNECAF is more protective and conservative compared to PNECSSD. The findings of this study have significant implications for PFOS and PFOA risk assessment in aquatic environments. Thus, it will aid freshwater sustainability and safeguard the human dependency on water resources.
Fauna of Cladocera (Crustacea: Branchiopoda) of Sabah state of Malaysia, Borneo Island, was evaluated for the first time. Samples from 40 locations were studied, and 31 species of Cladocera were revealed, including three species of Sididae, one species of Daphnidae, one species of Moinidae, four species of Macrothricidae, two species of Ilyocryptidae, and 20 species of Chydoridae. One species of Ilyocryptidae, Ilyocryptus yooni Jeong, Kotov and Lee, 2012, is recorded for Malaysia for the first time, and one more, Anthalona sp., is probably new for science. Of 31 species recorded for Sabah, only three are true planktonic species and 28 are substrate-associated species. Absence of large natural lakes, habitats with most rich cladoceran fauna, can be an important factor limiting diversity of Cladocera in Sabah.
Study of Ephemeroporus Frey, 1982 populations from Peninsular Malaysia revealed a new species. Ephemeroporus malaysiaensis sp. nov. is characterized by the presence of four-five large denticles on anal margin of postabdomen instead of two-three, and five distinctive pigmented spots on each valve. Pigmented spots on the valves were never recorded for any species of family Chydoridae. E. malaysiaensis sp. nov. seems to be another endemic Chydoridae species of South-East Asia. E. malaysiaensis sp. nov. is a rare species, associated with emergent macrophytes in the littoral zone of shallow lake. Most of Ephemeroporus populations from Peninsular Malaysia belong to eurybiotic Paleotropical species Ephemeroporus barroisi (Richard, 1984).
Matched MeSH terms: Cladocera/anatomy & histology; Cladocera/classification*; Cladocera/growth & development
Acute and chronic effects of insecticide-endosulfan on the survival and reproduction performance of Moina macrocopa were determined in a laboratory study. Endosulfan concentrations that cause 50% mortality (LC50) after exposure for 24 and 48 h were 3.34 and 0.16 mg L(-1), respectively. Average longevity, initial age of reproduction and intrinsic rate of natural increase were reduced at 0.002 mg L(-1). Fecundity was greatly reduced by about 70% at 0.0004 mg L(-1) and approximately 97% at 0.002 mg L(-1) as compared to control organisms throughout the whole life span of 15 days. If environmental concentration of endosulfan do not exceed 0.0004 mg L(-1), application of this insecticide is unlikely to induce detrimental effects on these cladoceran populations in agro-ecosystem.
The distribution and abundance of zooplankton species of Harapan and Aman
Lakes were investigated in relation to physical parameters and chlorophyll-a content. Both
lakes were characterised by the occurrence of algal bloom problem. The composition of
zooplankton was collected at monthly intervals from November 2013 to February 2014.
The total number of taxa in Harapan and Aman Lakes were 23 and 27, respectively.
Rotifera was the highest abundance group represent 64% of the total species recorded
followed by Copepoda (29%) and Cladocera (7%). Three dominant zooplankton that been
recorded in both the lakes are Brachionus forficula, Brachionus nilsoni, and Trichocerca
sp. High abundance of these species indicates that the lakes are eutrophic water bodies.
Overall, zooplankton species distribution and abundance in the study sites are influenced
by various environmental factors such as water transparency and chlorophyll-a content.
Unlike those in the mainland of Southeast Asia, the Cladocera of the Malay Archipelago has not been intensively studied, except for the state of Sabah in the north-eastern part of the Borneo island. This study aimed to complete the inventory of the Cladocera in Sabah by looking at different types of water bodies including oxbow lakes, small lakes, reservoirs, ponds, ditches and paddy fields. From 32 sites examined, 35 species of cladocerans, nine of which were new records to Sabah, were found from 25 localities. With this new finding, the total number of cladoceran species in Sabah increased to 39 species, including five species of Sididae, four species of Daphniidae, one species of Moinidae, five species of Macrothricidae, two species of Ilyocryptidae, and 22 species of Chydoridae. Only 8 % ( three species) of Sabah cladocerans are true planktonic. This study illustrated that most cladocerans were associated with substrates in the littoral zone and thus appropriate sampling methods should be employed in different microhabitats for comprehensive biodiversity assessment.
Zooplankton were sampled in Lake Ikeda at a fixed station every month with the aid of a plankton net in order to observe whether cyclomorphism was exhibited by the neonates of Bosmina longirostris. In Lake Ikeda the relative sizes of the antennules and mucrones of B. longrostris neonates decreased in relation to carapace length from 65% in winter to 50% in summer. Mucrone lengths also decreased from 30% in winter to 20% in summer. Both appendages were inversely correlated with surface temperature of the lake. Predation seems to be one of the reasons why neonates of B. longirostris exhibited seasonal cyclomorphism in their antennule and mucrone.