| abstract | Trhypochthoniellus comprises nine species, being mostly associated to aquatic vegetation; T. chilensis Ermilov & Weigmann as the only known species from North and South America. This genus is recorded for the first time in Mexico. Herein we present the description, illustrations and SEM photographs of Trhypochthoniellus churincensis sp. nov., which was found in association to lignocellulolytic microfungal taxa in the oligotrophic freshwater oasis of Cuatro Ciénegas Basin, Coahuila, México. T. churincensis sp. nov. is morphologically similar to T. longisetus (Berlese) and T. brevisetus Kuriki; however, it differs from both taxa by the presence of nine genital setae (11 to 13 setae), setae h3 subequal to other posterior notogastral setae; subcapitular setae h very short, and notogastral c1 larger. Additionally, we discuss information on food preferences and reproductive mode obtained through the observation of one cultured population maintained under laboratory conditions. A key to the species of Trhypochthoniellus is provided. |