| Author Title Journal |
Brehm V (1943) Das Disjunktionsproblem und die Siisswasserfauna. [The problem of discontinuous distribution and the freshwater fauna]. Arch f Hydrobiol 40(2): 589-614 |
Abstract / Notes
In discussing this problem the author lists some spp. recognized recently to be boreo-alpine: Arcticocamptus rhaeticus, A. arctiens, A. cuspidatus, A. van douwei, Moraria duthiei among the Harpacticida, the Ostra-coda spp. Leucocythere mirabilis, the Chironomid sp. Eukief-feriella cyanea and the turbellarians Otomesostoma auditivum, Dalyellia bardeaui and Castrada luteola. In some cases the discontinuous distr. of spp. occurring in n. Europe and in the Alps may be explained more easily by the theory of Scharff, according to which the animals did not reach their present areas starting from the ice-free regions in middle Europe after the diluvial period, as Zschokke has pointed out, but migrated from Asia along 2 paths entering northern Europe and the Alps independently. The organisms entering the Alps are considered to have used the broad land connection existing in the Miocene Age between Asia Minor and the Balkans. Diaptomus laticeps, for example, occurs in Scandinavia, the British Isles, the Balkans and the southern Alps, but is missing in the northern Alps. Heterocope appendiculata is distr. in the Baltic regions and in Montenegro. These facts cannot be explained by Zschokke's theory.
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