Quarterly sampling campaigns were carried out during year 2019 to study the effects of organic pollution on the diversity and abundance of meiofauna from a polluted coastal system in north-western Mexico. Amongst harpacticoids, the family Miraciidae Dana 1846 was by far the most abundant and diverse, and several new species and the proposal of some new genera of Stenheliinae Brady 1880 and Diosaccinae Sars 1906 will be published elsewhere. Amongst the Diosaccinae, the genus Robertgurneya Apostolov & Marinov 1988 was one of the most abundant. This genus was proposed and diagnosed by Lang (1944, 1948) but after a complex taxonomical history, was made available by Apostolov & Marinov (1988) who proposed an amended diagnosis and designated R. similis similis (Scott A. 1896) as the type species of the genus. Here I propose a new species, Robertgurneya mexicana sp. nov., and give a fully illustrated record of the widely distributed R. rostrata (Gurney 1927). The relationships amongst the species of Robertgurneya are not clear, but the new Mexican species shares with R. falklandiensis (Lang 1936) the elongated inner dimorphic spine on the basis of the male P1. Additionally, a new amended diagnosis for the genus Robertgurneya, as well as the reallocation of R. soyeri (Apostolov 1974) into Typhlamphiascus Lang 1944, and the creation of a new genus, Robertgurneyella gen. nov., for R. spinulosa (Sars 1911) are proposed.