Published online by Cambridge University Press: 18 October 2007
This article is a review of the genus Richtersia (Nematoda: Selachinematidae) with a key to species, genus diagnosis and lists of valid species. Two new Richtersia species from the Golfo San José and Golfo San Matías, Chubut province of Argentina are described: Richtersia bicornis sp. nov. is characterized by having two thorn structures after cuticular collar, and in total 32–40 longitudinal rows of spines arranged in eight groups in cervical region and precloacal spines similar in shape. Richtersia argentinae sp. nov. is characterized by the number of longitudinal rows of spines, amphid size and the precloacal spines configuration.