Towards a revision of the genus Parastenocaris Kessler, 1913:: establishment of Simplicaris gen. nov from groundwaters in central Italy and review of the P-brevipes-group (Copepoda, Harpacticoida, Parastenocarididae)

A new genus Simplicaris (Copepoda, Harpacticoida, Parastenocarididae) is established to accommodate two species collected from deep groundwater in Italy, S. lethaea sp. nov. and S. veneris (Cottarelli & Maiolini, 1980) comb. nov. Parastenocaris hippuris Hertzog, 1938 and R aedes Hertzog, 1938 are ranked as incertae sedis within the genus. Members display complete absence of leg 5 in both sexes and an unusual elongation of the first exopodal segments of legs 1-4, in which exp-1 is distinctly longer than exp-2 or -3, or as long as exp-2 and -3 combined. As the systematic status of the family Parastenocarididae and of the type genus Parastenocaris is still in flux, a list of phylogenetically informative characters is proposed, along with a discussion of their various states in representative members of the family The genus Parastenocaris sensu stricto is redefined to comprise only the brevipes-group. The remaining members of the genus are considered Parastenocaris sensu lato pending a thorough revision of the family. (C) 2004 The Linnean Society of London, Zoological Journal of the Linnean Society.