The subarctic ancient Lake El'gygytgyn harbours the world's northernmost 'limnostygon community' and reshuffles crangonyctoid systematics (Crustacea, Amphipoda).

The northward distribution limit of groundwater fauna is generally dictated by the extent of glacial ice sheets during the Pleistocene. However, some taxa can be found far above this limit, sometimes on isolated oceanic islands, implying long-term survival in subglacial subterranean refugia. Here we report a peculiar assemblage comprising two new depigmented and blind (stygomorphic) amphipods from the subarctic ancient lake El'gygytgyn (northern Far East): Palearcticarellus hyperboreus sp.

Phylogenomic analysis of the Lake Kronotskoe species flock of Dolly Varden charr reveals genetic and developmental signatures of sympatric radiation.

Recent adaptive radiations provide experimental opportunities to parse the relationship between genomic variation and the origins of distinct phenotypes. Sympatric radiations of the charr complex (genus Salvelinus) present a trove for phylogenetic analyses as charrs have repeatedly diversified into multiple morphs with distinct feeding specializations. However, charr species flocks normally comprise only two to three lineages.

Phylogenomic analysis of the Lake Kronotskoe species flock of Dolly Varden charr reveals genetic and developmental signatures of sympatric radiation.

Recent adaptive radiations provide evolutionary case studies, which provide the context to parse the relationship between genomic variation and the origins of distinct phenotypes. Sympatric radiations of the charr complex (genus ) present a trove for phylogenetics as charrs have repeatedly diversified into multiple morphs with distinct feeding specializations. However, species flocks normally comprise only two to three lineages.

Metapopulation Structure of Two Species of Pikeworm (, Cestoda) Parasitizing the Postglacial Fish Community in an Oligotrophic Lake.

In the present study, we estimated the levels of infestation of the main fish species that are hosts for two species: and . The prevalence of and infestations in the intestine of their definitive host-pike was similar (71.0% and 77.

Bone calcification rate as a factor of craniofacial transformations in salmonid fish: Insights from an experiment with hormonal treatment of calcium metabolism.

Adaptation to different environments can be achieved by physiological shifts throughout development. Hormonal regulators shape the physiological and morphological traits of the evolving animals making them fit for the particular ecological surroundings. We hypothesized that the artificially induced hypersynthesis of calcitonin and parathyroid hormone mutually influencing calcium metabolism could affect bone formation during early ontogeny in fish imitating the heterochrony in craniofacial ossification in natural adaptive morphs.