Abstract
The fish parasite Neoechinorhynchus baueri Mikhailova et Atrashkevich, 2019 is currently widely distributed in AsiaНs subarctic zone. To find the ecological adaptations that enable this species to colonize northern habitats, an experimental study of the acanthocephalan post-embryonic development in intermediate hosts was conducted at the IBPN Chaun station (Western Chukotka). to the research aimed in determining the duration of larval development in the wild. Under the environmental temperature conditions in Chukotka, this period amounts to 40-47 days; however, the regime of variable temperatures prevented identifying the most favorable range on the scale. New experiments, conducted later in Magadan at controlled temperatures, showed larvogenesis acceleration double the temperature increase to 22-25 °C. The eurythermal properties detected in the parasite may ensure its spread in the southern regions of Siberia and of the Far East.