Feeding habits shape infection levels by plerocercoids of the tapeworm Triaenophorus crassus in muscle of a sympatric pair of whitefish in an oligotrophic lake.

Lake Teletskoye (West Siberia, Russia) is inhabited by a sympatric pair of whitefish, with each member of the pair being characterized by different feeding habits. Coregonus lavaretus pidschian (Gmelin, 1789) is a large 'benthivorous' form, while C. l. pravdinellus (Dulkeit, 1949) is a small 'planktivorous' form. Fish were collected from the end of August to the middle of September in 2017 and 2019-2020 in the north part of Lake Teletskoye. For the 'benthivorous' form the prevalence, intensity and abundance of T. crassus ranged from 22.4% to 51.9%, 1.9-2.8 and 0.4-1.3, respectively, whereas the same indices for the 'planktivorous' form ranged from 94.7% to 97.5%, 4.2-4.8 and 4.0-4.7, respectively. The level of prevalence of infection and abundance of T. crassus in muscle was relatively stable among studied years for both forms. The level of prevalence was higher in the years 2019 and 2020 than in 2017 for the 'benthivorous' form, whereas for the 'planktivorous' form this index did not change during the studied years. For the first time, a partial sequencing of the cox1 gene (593 bp) for T. crassus was sequenced. All 15 plerocercoids of T. crassus were represented by four haplotypes.

[Genetic polymorphism, haplotype distribution, and phylogeny of Daphnia (Cladocera: Anomopoda) species from the water bodies of russia as inferred from the 16S mtDNA gene sequencing].

The data on the genetic polymorphism of the most widespread Daphnia species occupying different water bodies of Russia are presented. The phylogenetic relationships between the examined species were established, and the haplotype networks were constructed. A fragment of the 16S mitochondrial DNA gene was used as a genetic marker. The results of molecular phylogenetic analysis generally coincided with modern concepts in the systematics of the genus Daphnia. The representatives of the divergent mitochondrial lineages within the D. longispina, D. pulex, and D. magna complex remain poorly investigated morphologically. For D. dentifera, a new habitat on the territory of Russia, namely, the water bodies of the Lake Baikal basin, was identified. A conclusion was made that the 16S mtDNA gene could be successfully used in phylogeographic analysis of the genus Daphnia.

[Molecular genetic identification and phylogeny of Daphnia species (Crustacea, Cladocera) from water bodies of Lake Chany basin].

The data on the molecular genetic identification of Daphnia species from the water bodies of Lake Chany basin are presented. Phylogenetic relationships between these species have been established. The fragments of the mitochondrial DNA 16S and 12S genes were used as genetic markers. According to the data obtained, the water bodies examined were inhabited by five Daphnia species, including Daphnia (Daphnia) galeata Sars, D. (D) longispina O. E Müller, D. (D) curvirostris Eylmann, D. (D) pulex Leydig, and D. (Ctenodaphnia) magna Straus. In addition, a group of longispina-like individuals that form a separate phylogenetic cluster was identified.