Search

Eisenia nordenskioldi (Eisen, 1879) is the only autochthonous Siberian earthworm with a large distribution that ranges from tundra to steppe and broadleaved forests. This species has a very high morphological, ecological, karyological, and genetic diversity, so it was proposed that E. nordenskioldi should be split into several species. However, the phylogeny of the complex was unclear due to the low resolution of the methods used and the high diversity that should have been taken into account. We investigated this question by (1) studying the diversity of the COI gene of E. nordenskioldi throughout its range and (2) sequencing transcriptomes of different genetic lineages to infer its phylogeny. We found that E. nordenskioldi is monophyletic and is split into two clades. The first one includes the pigmented genetic lineages widespread in the northern and western parts of the distribution, and the second one originating from the southern and southeastern part of the species' range and representing both pigmented and non-pigmented forms. We propose to split the E. nordenskioldi complex into two species, E. nordenskioldi and Eisenia sp. 1 (aff. E. nordenskioldi), corresponding to these two clades. The currently recognized non-pigmented subspecies E. n. pallida will be abolished as a polyphyletic and thus a non-natural taxon, while Eisenia sp. 1 will be expanded to include several lineages earlier recognized as E. n. nordenskioldi and E. n. pallida. [ABSTRACT FROM AUTHOR]

Summary: Two new nematode species of Phasmarhabditis were isolated from land snails in North and West Caucasus, Russian Federation. Phasmarhabditis circassica sp. n. originated from Oxychilus sp. collected by the Nickel settlement in the Adygea Republic while P. clausiliiae sp. n. came from Clausiliidae gen. sp. in the Stavropol district. Phasmarhabditis circassica sp. n. is characterised morphologically by male spicules with a hollow tip, a widely conoid, spicate female tail, ensheathed dauer juveniles 896 (813-982) μ m long with a tiny but distinct cuticular apical cap and a long filamentous tail, and exsheathed dauers 773 (670-950) μ m long with a tail half as long as in the ensheathed dauers and with a rounded tip. Phasmarhabditis clausiliiae sp. n. is very close to P. circassica sp. n. in having similar morphological traits and is differentiated mainly in having a longer female tail of 94 (79-111) vs 82 (54-125 μ m) and the much smaller ratio c of 13.7 (10.3-18.4) vs 22.7 (16.8-27.5) and by its molecular characteristics. The molecular analysis based on partial sequences of LSU rDNA, and ITS rDNA regions has been performed and showed that the closest match for both new species was P. bohemica. Despite the morphological similarity between the species described, significant difference between these two new species was reported both for LSU rDNA and ITS rDNA. [ABSTRACT FROM AUTHOR]