Steinernema minutum Maneesakorn,Grewal & Chandrapatya. 2010

Abstract : A new entomopathogenic nematode Steinernema minutum from Thailand is described. Steinernema minutum is characterized by the small size of its infective juveniles (403, 364-455 µm), the location of the excretory pore from the anterior end (34, 31-36 µm), the length of pharynx (95, 85-99 µm) and D% (40, 35-46%) in the infective juvenile, SW% of the first generation male (185, 134-231%), inconspicuous mucron in the first generation male, a prominent mucron (3-4 µm long) in the second generation male, slightly protruding vulval lips with a double epiptygma in the first generation female and no postanal swelling in the second generation female. Hybridization assays between S. minutum and Steinernema siamkayai yielded no progeny. The phylogenetic tree based upon the ITS sequence of 852 base pairs placed S. minutum in the same clade with S. siamkayai, Steinernema tami, Steinernema cumgarense and Steinernema eapokense but shared less than 97% similarity with these sister taxa. The symbiotic bacteria isolated from S. minutum determined by 916 base pairs of the 16S rDNA sequence showed 100% similarity to Xenorhabdus stockiae, the symbiont of S. siamkayai.

The epithet is based on the small body of the species.