Rediscovery and redescription of Austriocyclops vindobonae Kiefer, 1964 (Copepoda, Cyclopoida) with remarks on the subfamily Eucyclopinae Kiefer

Since the publication of the description of Austriocyclops vindobonae Kiefer, 1964, all known material was represented by a single female collected in a groundwater well in Vienna (Austria), characterized by a strong reduction of leg 5. The recent discovery of several specimens of A. vindobonae in phreatic waters in Vienna allows a redescription of the female and the first description of the male. The rudimentary fifth leg consists of one or two setae and resembles that of some Cyclopinae genera; however, the presence of tube-like, plumed aesthetascs on the male antennula and the spine pattern of the basipod of the antenna reveal that the genus Austriocyclops belongs to the subfamily Eucyclopinae. The inadequacy of using the fifth leg in the definition of this subfamily is discussed, and new characteristics for definition (shape and location of aesthetascs on male antennule and ornamentation pattern of antenna basipod) are proposed.