Scientific publications

The taxon Daptonema is very species-rich, with more than 113 valid species from all over the world, occurring in all types of marine, brackish and freshwater habitats. Despite of Daptonema species being are of the most abundant nematode in the sand sediments over the world, this is the first report of this species in Far Eastern Seas. The estuary of the Amur River is the largest estuary of the eastern coast of Russia. Geographically it is located between the Japan Sea and the Okhotsk Sea. A total of 233 species of nematodes was recorded, 15 species of Daptonema were reported from this estuary. Some species (D. articulatum, D. ecphygmaticum, D. longissimecaudatum, D. normandicum, D. procerum, D. tenuispiculum) are widely distributed. In order to unravel the possible relationships between Daptonema species the distribution of species were analyzed in relation to environmental and geographical distribution. The spatial distributions of these nematodes were strongly correlated with salinity. Daptonema (sensu Lorenzen, 1977) represents heterogeneous group, particularly in the structure of their copulatory apparatus, are difficult in relation to taxonomy and systematics. The genus suffers from troubled taxonomy and many species cannot be identified with certainty. There are few morphological characteristics used as distinctive parameters: setae length, amphidial fovea size and position; copulatory apparatus size and structure; tail shape and length. Moreover this genus contains species complexes. Results will hopefully lead to taxonomic revisions of Daptonema Cobb, 1920 and give a better picture of evolution within the major group of nematodes. This work was supported by grant from Russian Government № 11.G34.31.0010.