Revision of Rogneda Uljanin, 1870 (Rhabditophora, Eukalyptorhynchia, Polycystididae) with the description of seven new species

Abstract

A morphological and taxonomical account of the taxon Rogneda is given. A new interpretation of the stylet morphology is presented and a new terminology pertaining to these hard parts is proposed. All known species are discussed and additional information is provided when necessary. Seven new species are described. Five of these are from the Mediterranean: R. colpaerti sp. nov., R. licyae sp. nov., R. schaereri sp. nov., R. valckei sp. nov. and R. vangronsveldi sp. nov. R. verveckeni sp. nov. is from the Atlantic coast of Spain (Galicia). The seventh, R. martensi sp. nov., is from Indonesia and is the first species of Rogneda to be found outside the Northeast Atlantic and the Mediterranean. All new species can be recognized based on the morphology of the stylets in the male system. A discussion on the similarities and differences of the 22 species is provided, resulting in the grouping of the species into seven morphological groups: the capulata-group, the falcata-group, the hibernica-group, the polyrhabdota-group, the steueri-group, the tripalmata-group and the westbladi-group. R. minuta cannot be placed into any of these groups and therefore stands alone within the taxon. An identification key is provided to facilitate further study of the taxon Rogneda.