Steinernema schliemanni sp n. (Steinernematidae; Rhabditida) - a new species of steinernematids of the 'monticolum' group from Europe

摘要

Steinernema schliemanni sp. n. found on the surface of a cadaver of Osmoderma ceremita (Coleoptera) in Germany in April 2003 is described. The new species belongs to the group of species related to S. monticolum ('monticolum'-group). It differs from the other species of this group in the structure of the lateral field of infective juveniles, viz. 8 equal ridges at mid-body in S. schliemanni sp. n. vs unequal ridges in S. monticolum and S. robustispiculum and five ridges in S. ashiuense. Infective juveniles of S. schliemanni sp. n. are longer (842-1008 mu m) than those of all other species of the 'monticolum' group. Steinernema schliemanni sp. n. differs from the other species of the 'monticolum'-group in at least 115 positions of the ITS rDNA sequence (18%). The nucleotide difference of the D2D3 region of the LSU rDNA between S. schliemanni sp. n. and the closest species, S. monticolum, is 22 bp (3.9% of the compared sequences), which is higher than differences between species such as S. feltiae, S. kraussei and S. oregonense. The 16S rDNA sequence of the bacterium associated with S. schliemanni sp. n. demonstrates close relationships with several Xenorhabdus species; the nucleotide difference is the lowest with X hominickii (28 bp or 2%), isolated from S. monticolum.