<i>Steinernema tarimense</i> n. sp. (Rhabditida: Steinernematidae), a new entomopathogenic nematode from Tarim Basin, Xinjiang, China

A novel entomopathogenic nematode (EPN) species, <i>Steinernema tarimense</i> n. sp., was isolated from soil samples collected in a <i>Populus euphratica</i> forest located in Yuli County within the Tarim Basin of Xinjiang, China. Integrated morphological and molecular analyses consistently place <i>S. tarimense</i> n. sp. within the '<i>kushidai-</i>clade'. The infective juvenile (IJ) of new species is characterized by a body length of 674-1010 μm, excretory pore located 53-80 μm from anterior end, nerve ring positioned 85-131 μm from anterior end, pharynx base situated 111-162 μm from anterior end, a tail length of 41-56 μm, and the ratios D% = 42.0-66.6, E% = 116.2-184.4, and H% = 25.5-45.1. The first-generation male of the new species is characterized by a curved spicule length of 61-89 μm, gubernaculum length of 41-58 μm, and ratios D% = 36.8-66.2, SW% = 117.0-206.1, and GS% = 54.8-82.0. Additionally, the tail of first-generation female is conoid with a minute mucron. Phylogenetic analyses of ITS, 28S, and <i>mt12S</i> sequences demonstrated that the three isolates of <i>S. tarimense</i> n. sp. are conspecific and form a sister clade to members of the '<i>kushidai-</i>clade' including <i>S. akhursti</i>, <i>S. anantnagense</i>, <i>S. kushidai</i>, and <i>S. populi.</i> Notably, the IJs of the new species exhibited faster development at 25°C compared to other <i>Steinernema</i> species. This represents the first described of an indigenous EPN species from Xinjiang, suggesting its potential as a novel biocontrol agent against local pests.