Steinernema ichnusae sp. n. (Nematoda: Steinernematidae) a new entomopathogenic nematode from Sardinia Island (Italy)

• Published in: Journal of invertebrate pathology Vol. 99; no. 2; pp. 173 - 185
• Main Authors: Tarasco, Eustachio, Mráček, Zdenek, Nguyen, Khuong B., Triggiani, Oreste
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.10.2008
• Subjects: 28S rDNA sequence; Animals; Entomopathogenic nematode; Female; Italy; Male; Molecular taxonomy; New species; Phylogeny; rDNA ITS sequence; Rhabditida - anatomy & histology; Rhabditida - classification; Rhabditida - genetics; Sardinia; Steinernema ichnusae sp. n; Italy; 28S rDNA sequence; rDNA ITS sequence; Sardinia; Steinernema ichnusae sp. n; New species; Entomopathogenic nematode; Phylogeny; Molecular taxonomy
• ISSN: 0022-2011; 1096-0805
• DOI: 10.1016/j.jip.2008.05.001

A new Steinernema 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 first 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.