New species Eutobrilus Gagarini sp. n. and a review of species of the genus Eutobrilus from graciliformis-group (Nematoda: Tobrilida, Tobrilidae, Eutobrilinae)

A new species of Eutobrilus gagarini sp. n. from the Leningrad region is described, which included in morphological graciliformis-group genus and differs other group by a high coefficient "b" smaller ratio length spicules to supplementary row body. key for determining Holarctic given composition structure this as whole are discussed. The expediency isolating synonymization Peritobrilus Gagarin, 1993 with Tsalolikhin, 1981 confirmed.