A review of the genus Vitrea Fitzinger, 1833 (Gastropoda, Eupulmonata, Pristilomatidae) in Serbia: diversity, distribution and the description of a new species.

In this paper, the genus Vitrea Fitzinger, 1833 in Serbia is reviewed. All previous literature data on this genus from Serbia are summarised and used to discuss its distribution in the country and create distribution maps, supplemented by new material collected by the authors. All Serbian species are figured. For each species, a brief description of the examined specimens, data on previous findings in Serbia, the material (including types) that were analysed, the distribution and habitats in Serbia they inhabit, as well as remarks on specific species are given. A new species, Vitreavirgo Gojsina & Dedov, sp. nov., is described from a pit on Mt. Devica in eastern Serbia. Vitreapygmaea (O. Boettger, 1880) is reported for the first time for the territory of Serbia. As some Vitrea species have a narrow geographical range and prefer certain habitats, they are particularly vulnerable to habitat changes, which is also discussed in the paper. An identification key for all hitherto known Serbian species is given.

Operculum shape variation in Theodoxus Montfort, 1810 (Gastropoda: Neritidae).

The operculum morphology of neritid snails of genus Theodoxus Montfort, 1810 yields important species-specific taxonomic characters. This study is the first attempt to describe morphological differences in snails based on operculum shapes using a geometric morphometric approach. We examined the variability of opercular shapes between sexes and among populations and species based on 91 opercula of adult specimens belonging to six populations of three species of Theodoxus from the central Balkan and the southern border of the Pannonian plain. There are no sex-related differences in operculum shape and size in the studied species. The presence of shape variations influenced by size (allometry) was confirmed for T. danubialis (C. Pfeiffer, 1828) indicating that allometry could be a component of the morphological variation of this species. At the intraspecific level, phenotypic plasticity of operculum shape was found in T. danubialis and T. fluviatilis (Linnaeus, 1758). Of particular interest is the lack of morphological variability in the rare and endangered T. transversalis (C. Pfeiffer, 1828). At the species level a clear morphological distinction of T. fluviatilis from T. danubialis and T. transversalis was detected, confirming that the operculum with a rib could be used as a species-specific morphological character. The main morphological differences between species are an outwardly-stretched opercular/apophysal rib and a shortened tip of the opercular plate in T. fluviatilis, compared to the same structures in T. danubialis and T. transversalis.

Morphological differentiation of seven species of the genus Heterocypris Claus, 1892 (Ostracoda, Crustacea) based on the upper lip.

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.