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In order to illuminate taxonomic significance of cyst variability (as a part of total morphological variability) in the genus Branchipus, cysts (fertilized eggs) originating from southern parts of the Pannonian Plain are described on the basis of scanning electron microscopy (SEM) observations. The present study sets out to: 1) improve knowledge on use of egg morphology as a reliable taxonomic criterion in the genus Branchipus; 2) discuss egg variability in Pannonian populations; and 3) briefly discuss possible adaptive implications of egg morphology from the evolutionary point of view.

During 2004 conchostracans Imnadia and Leptestheria were recorded near the Serbian-Bulgarian border, in the foothills of the Western Stara Planina Mountains. Leptestheria occurred in relatively large density and was presented by adults of both sexes. Imnadia was identified only by resting eggs separated from the pond sediment. This is the first report of genus Imnadia in the Balkans, and also a first record of the second genus in the limnological area of the "Eastern Balkans".

Widely distributed in Europe, the genus Branchipus is found only at several localities in the Balkans. One locality in Western Macedonia is inhabited by B. intermedius (the only known locality of this species known other than the type locality in Romania), the others by B. schaefferi.

Morphological differences of upper lip shape were analyzed in seven Heterocypris species occurring in the Mediterranean region. Descriptive observations and morphometric analysis of upper lip length, height and maximum height position are given for 17 populations from the Pannonian Plain, Balkan Peninsula and Iberian Peninsula. We found high variation in relative upper lip measurements between the species, indicating that upper lip traits can be used as additional taxonomic characters. The most distinctive upper lip shapes were noted in H. exigua and H. gevgelica, while the greatest intraspecific variability was present in H. barbara, H. incongruens and H. rotundata. Previously described qualitative characters in the form of differently arranged patches of pseudochaetae on the upper lip surface were also observed.