ИСТИНА

We report the finding of specimens of priapulids collected near the White Sea Biological Station. One of these clades is close to Priapulus caudatusand may represent this species, whereas the other clade is likely to represent a new species. In four studied marker genes Priapulus sp. forms a clade, which is clearly separated from P. caudatus.Phylogenies for all the studied genes are robust and allow us to consider two sympatric species of Priapulus in the White Sea. Investigation of the morphological characters (pharyngeal teeth, scalids, caudal papillae, tail, colour, size) show some variation, but the differences do not clearly characterize the two clades. There are some unique characters in particular specimens, which must be regarded as individual modifications, this accounts especially to the pharyngeal teeth. Only a restricted number of specimens could be investigated, but the main problem is that even for the best known species, Priapulus caudatus, the complete series of character changes during development is not well documented. Therefore, it is difficult to compare stages of priapulids of different size and presumably different age. Molecular genetic analyses arevery helpful, but the exact morphological characterization of species remains a challenge for future investigations.