Three new genera, two new species and one new combination of family Hystrignathidae (Nematoda: Thelastomatoidea) from Ceracupes fronticornis (Westwood) (Insecta: Passalidae) in China.

Two new genera and two new species of family Hystrignathidae were collected from Ceracupes fronticornis (Westwood) from the Yunnan Province, China. Pseudoxyo yunnanensis gen. et sp. nov. differs from the related genera by having the cervical region armed with alternating rows of spines, with 22 spines in the first row, and by lacking the first cephalic annule. Sinospinata chitwoodi gen. et sp. nov. can be easily distinguished from the related genera by having the cervical region of females armed with irregularly arranged spines, two or three spines clustered together in their roots in some spines. Meanwhile, Huntinema gen. nov. was proposed to replace Huntia Zhang, Yin, Carreno & Zhang, 2021 because the name of this genus was preoccupied by Huntia Gray & Thompson, 2001 for placement of two new species of spiders. In addition, the 18S and 28S rDNA partial sequences of two new species were obtained.