Steinernema
ichnusae Tarasco et al.,
2008
Summary: inernema species
was isolated from three different sandy soil samples along the Platamona Beach,
in the north-west coast of Sardinia Island (Italy). This new species is
characterized by the following morphological characters: infective third-stage
juvenile with a body length of 866 ± 61 (767–969) µm, distance from head to
excretory pore of 63 ± 2.7 (59–68) µm, tail length of 81 ± 3.2 (76–89) µm,
ratio E (%) 77 ± 3.4 (68–83); male tail
with a mucron only in the second generation, spicule length of 66 ± 1.4 (64–67)
µm and gubernaculum length of 44 ± 1.4 (43–46) µm in the first generation male;
female of irst generation with a slight vulval protrusion and ratio D (%) of 53 ± 4.0 (47–63). The new species differs distinctly from
the related species (S. feltiae, S. kraussei, S. litorale,
S. oregonense and S. cholashanense) in some morphometric values such
as percentage of hyaline portion, ratios of gubernaculum/spicule length, spicule
head length/width. The DNA analyses of the internal transcribed spacers and
D2D3 regions show that the studied nematode isolates are a new species. Cross
hybridisation tests with S. feltiae, S. kraussei, S.
litorale, S. weiseri and S. oregonense showed that these species were reproductively isolated.