ИСТИНА

Tantulocarida is a class of tiny parasitic crustaceans recognized only 30 years ago by Boxshall and Lincoln (1983). They are characterized by a very complicated life cycle including both ectoparasitic and free-swimming stages representing partenogenethic and sexual phases. Tantulocarida maybe the most poorly studied group among Crustacea, their internal structures has never been described using TEM, their relationships with other crustaceans are far from being understood, their life cycle is not fully reconstructed. Intrinsic phylogeny of the group has not been reviewed since 1996 (Boxshall, 1996), and it became clear that the systematics of Tantulocarida is more likely artificial, while formal cladistic analysis has never been carried out at all. Currently, four families of Tantulocarida are recognized: Basipodellidae, Deoterthridae, Microdajidae and Doryphallophoridae. Formal cladistic analysis of the group was conducted for the first time, 64 morphological characters of tantulus larva and adult males were used to estimate the relationship between 34 out of 36 currently described species, belonging to four families. Bootstrap and neighbour joining trees constructed in Paup 4.0 revealed the following results: 1. Families Deoterthridae, Basipodelidae and Doryphallophoridae are more likely polyphiletic 2. The only monophyletic family is Microdajidae. 3. Three monophyletic genera are recognized: Arcticotantulus, Tantulacus and Deoterthron. 3. Previously existing family Onceroxenidae is now formally considered to be invalid as its diagnosis is based on the incorrect features. Our results also show that even such an extensive dataset is not enough to reconstruct the tree of Tantulocarida mainly because real biodiversity of the class is underestimated and it is impossible to score all characters for all known tantulocaridan species due to the insufficient description.