Occurrence and ecological characteristics of Mixodiaptomus kupelwieseri (Brehm, 1907) (Copepoda, Calanoida) in mountain water bodies of the northern Apennines, Italy

The calanoid copepod Mixodiaptomus kupelwieseri, widely distributed in southeastern Europe, is considered a typical inhabitant of lowland waters, both permanent and astatic. This species was first reported in the 1990's in the Ligurian and Emilian Apennines (northern Italy), where an extensive limnological campaign carried out from 1998 to 2000 demonstrated that it is quite common, mostly occurring up to an altitude of 1728 m a.s.l. in small pools that dry out in summer. The remarkably broader distribution of this species reported by the present research depends to a large extent on a greater sampling effort in temporary and ephemeral environments. Also, previous identification of calanoids in the study area might have been wrong. The possibility of a recent expansion of M. kupelwieseri in the northern Apennines is discussed. Notes on morphological variability and ecological traits of the species are also offered.