Ultrastructural, phylogenetic and rRNA secondary structural analysis of a new nematode (Nematoda: Tylenchomorpha) from mushroom with recovery of intestinal crystals

Abursanema quadrilineatum n. sp. was described both morphologically from light microscopy, scanning electron microscopy and transmission electron microscopy and molecularly based on 18S and 28S rRNA. The mycetophagous females were recovered from the old mushroom fruiting body of bracket fungus Trametes sp. growing on decaying wood. The new species is unique in Abursanema, indicated by the presence of four lateral lines. The secondary structures of the D2 and D3 domain of 28S rRNA were predicted for the new species and a general model for the superfamily Sphaerularioidea was built for comparative analysis. The ultrastructure of the cuticle, sperm cells and oocytes was examined and cuticle layers were defined. Needle-shaped crystals were recovered in mycetophagous female intestines and spermatheca, and chemical tests revealed that they are not composed of calcium oxalate or proteins.