Prendalona undetermined

39. ** Prendalona sp. (Fig. 4A–F) Localities and specimens found: 50 – 1♀. Distribution and ecology. This peculiar female was found amid the roots of a water hyacinth (see Appendix 1). Remarks. Based on the main diagnostic characteristics, this unidentified individual most likely belongs to the genus Prendalona and is most similar to P. (formely Alona) guttata (Sars, 1862) (Sousa et al. 2016 a, 2018; Sinev et al. 2023a). At the same time, it has a number of noticeable differences from P. guttata and other representatives of the genus; mainly the presence of atypically long (up to 38 μm) setae on the posterior parts of the ventral margin of the valves (Fig. 4A, B) (in other species, these setae are distinctly shorter) and the presence of a noticeably longer and thicker setula in the distal part of the groups of lateral setulae of the postabdomen (Fig. 4A, C, F) (in other species, these groups have the other configuration of the setulae in length and thickness) (Sinev et al. 2023a). Unfortunately, the only specimen found does not allow for a complete analysis of the morphological structure. It is possible that this is a new representative of the chydoridae. Further finds and study of more specimens are needed to clarify the status of this form.