Cunea russae Kudryavtsev et Volkova, 2020. Strain RUS17.3B.2 (RC CCMAm 0458)

Taxonomic assignment: Amoebozoa: Discosea: Dactylopodida: Paramoebidae This is the third cryptic species of the genus Cunea Kudryavtsev et Pawlowski, 2015. The previous two were isolated from the oceanic benthos (Western Atlantic Ocean, 5 km deep, and the Red Sea, ca. 59 m deep). By contrast, Cunea russae originates from the continental brackish-water habitat - Царицынский источник ("Tsaritsynsky Spring"), a fountain of underground brackish water (19 ppt) on the territory of the town of Staraya Russa (Старая Русса), Novgorod Region, northwest of Russia. What is really unique, is that this species shows no morphological differences from its marine counterparts (hence, "sibling species"). Primary reference: Kudryavtsev A, Volkova E (2020). Cunea russae n. sp. (Amoebozoa, Dactylopodida), another cryptic species of Cunea Kudryavtsev and Pawlowski, 2015, inhabits a continental brackish-water biotope. Eur. J. Protistol., https://doi.org/10.1016/j.ejop.2020.125685 Location: upper 1 cm of bottom sediments (sand with detritus) from Tsaritsynsky Spring (Town Staraya Russa, Novgorod Region, North-Western Russia); 57.98318N, 31.33482E. Reference culture: RC CCMAm 0458; kept with the Resource Centre "Culture Collection of Microorganisms" (Research Park, St-Petersburg State University) Imaging: Leica DM2500 upright microscope, Leica DFC495 video camera, 100x planapochromate oil immersion object lense with 1x camera adaptor, differential interference contrast. Observation conditions: Amoebae picked out from the culture, placed on a coverslip in a drop of medium and allowed to settle in a moist chamber. Then the coverslip is placed on a slide with the sealing Vaseline border to prevent the preparation from drying out too quickly. The preparation is then placed on the microscope with the coverslip up. Observation starts immediately. Contact: Dr. Alexander Kudryavtsev, Zoological Institute RAS and St-Petersburg State University (alexander.kudryavtsev@zin.ru); Ekaterina Volkova, Zoological Institute RAS (arcellinidae@gmail.com)