A New Species of (Nematoda: Coronostomatoidea) Parasite of (Coleoptera: Passalidae) from Mexico, and the Position of the Family in the Oxyuridomorpha.

A new species of the nematode Kloss, 1962 (Oxyuridomorpha), is described from the wood beetle Truqui from the mountain mesophilic forest in Hidalgo State, Mexico. n. sp. is distinguished from the other 4 congeners species by the presence of an expanded cervical ring, well-developed lateral alae, an obtuse cauda with a short and bifurcated caudal appendage, series of cuticular folds at ventral and dorsal body surface from excretory pore level to anal region, and ellipsoidal eggs ornamented with numerous small mushroom-like structures over the surface. The phylogenetic position of the new species is inferred based on a Maximum Likelihood and Bayesian Inference analysis of partial sequences of . The phylogenetic analysis showed that n. sp., the only representative of the Traklosiidae in our study, is closely related to and species of and all of them members of Hystrignathidae. These relationships are supported by high support values. The present study increases to 5 the number of species assigned to all of them parasites of Passalidae. Additionally, a taxonomic key to the species of the genus is provided.