It probably entered the aquarium as an egg or a larva on aquatic plants originating from south-east Asia. One female of the Australian-Oriental dragonfly Pseudagrion microcephalum emerged in a pet shop with fish aquaria containing tropical plants in Kraków (UTM: DA24) (S Poland) in February 2020. The description and report of this species highlights a possible introduction of an alien species to Japan, and facilitates further monitoring. Juveniles as well as adults were recovered, indicating that this species is reproducing in the pet trade, supporting the notion that it has invasive potential to areas outside of its natural range. The most likely origin is Southeast Asia, as evidenced by its close morphological resemblance to particular Southeast Asian species. We review the likelihood of both scenarios, and conclude that although there is insufficient evidence to be sure, it is potentially an alien species in Japan. in pet shops in Japan: it is either native to Japan but has yet to be discovered in its natural habitat, or it is an alien species, perhaps unwittingly imported with plants or fish for the pet trade. There are two scenarios to explain the existence of Pseudostrandesia tenebrarum sp. Of the nine previously described species in the genus, one is exclusively known from Turkey, and the others are found in Southeast Asia and the vicinity, one of which is also recorded in India and east China. It is the second species of the genus for which males are known. nov., is similar to four species previously reported from Southeast Asia, but can be distinguished by carapace and appendage features. This species, herein named Pseudostrandesia tenebrarum sp. Finally, the investigations highlight that the assessment of ingestion and egestion rates can help to clarify whether MPs remain in specific organisms and, thereby, become a potential health threat.Īn undescribed species of freshwater ostracod belonging to the genus Pseudostrandesia Savatenalinton and Martens, 2009 was collected from two pet shops in the Kanto region of central Japan. Furthermore, fragment uptake decreased slightly when co-exposed to food, but was not significantly different to the treatments without food. Medium- and small-sized beads were frequently ingested.
Particle shape did not significantly affect MP ingestion or egestion, but size was a relevant factor. Shrimps egested 59% of beads and 18% of fragments within 4 h. Our results demonstrate that the ingestion of beads and fragments were concentration-dependent. After each treatment, the shrimps were analyzed for retained or excreted particles. To simulate natural conditions, an additional fragment ingestion study was performed in the presence of food. Moreover, shrimps were exposed to 20,000 particles L⁻¹ of either 41 μm PE and 11 μm polystyrene (PS) beads or the PVC fragments for 24 h, followed by a post-exposure period of 4 h to analyze the excretion of particles. Therefore, organisms were exposed to 20–20,000 particles L⁻¹ of either polyethylene (PE) beads (41 μm and 87 μm) or polyvinyl chloride (PVC) fragments (<63 μm). To address this, we investigated if the ingestion and egestion of beads are different to those of fragments in the freshwater shrimp Neocaridina palmata. Furthermore, the accumulation of such particles in the gastrointestinal tract is likely to determine whether adverse effects are induced. However, the retention time and egestion of MPs have been examined less, especially for irregular MPs (fragments) which are predominantly found in the environment. The ingestion of microplastics (MPs) is well documented for various animals and spherical MPs (beads) in many studies.
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