ИСТИНА

Free-swimming definitive males of two species of the Tantulocarida Arcticotantulus pertzovi (Basipodellidae) and Microdajus tchesunovi (Microdajidae) were reared for the first time. Free-living individuals were studied using light microscopy, some aspects of their behavior especially the way of swimming were observed for the first time. Their morphology and ultrastructure were studied using scanning electron microscopy. A detailed analysis of morphological characters of all currently described species revealed several features typical of all known males of the tantulocaridans, such as 8 aesthetascs, 7 pairs of multifid sensillae on the head shield, paired brush setae on the protopods of thoracopods, three furcal setae etc. The morphology of the tantulocaridan males indicates the possible paraphyly of the families Deoterthridae and Basipodellidae, while the families Microdajidae and Doryphallophoridae are proved to be monophyletic.