Cryptaphelenchus diversispicularis n.sp. (Tylenchida, Aphelenchoididae) - a new nematode of the bark beetle, Ips subelongatus (Coleoptera, Ipidae).
The males, females and juvenile females of C. diversispicularis n.sp. are described. The inseminated immature females were found in the coxal depressions of the front legs of the imago of I. subelongatus, a pest of larches in the Magadan area, Far-Eastern USSR. C. diversispicularis is characterized by the dimorphism of spicules (the right spicule is longer with a better formed handle) and by the presence of one pair of preanal and 2 pairs of subterminal caudal papillae. The free-living stages were also found in the tunnels of Orthotomicus laricis or 2 other beetle species but no parasitic forms were found in these beetles. The new species is widespread in the examined area, 4.8% of young beetles in the Omolon and 12.5% in the Ten'kinsk district were infected, with 10 to 50 specimens/beetle. Flying stages appeared to carry the nematodes but none was actually found infected. The nematode was able to develop through several non-parasitic generations. The nematode culture survived for over a year on myceto-bacterial substrate, the "egg-to-egg" development took 4 days and the females laid an average of 8 eggs/day for 7 to 10 days. No morphological differences between free-living and parasitic females were observed.