The revision of the genus Trochulus Chemnitz, 1786 is based on conchological and anatomical characters of 4,377 adult specimens (3,190 dry shells and 1,187 alcohol-preserved snails) from 303 localities. Shell descriptions with the variation ranges, based on morphometric analysis, reproductive system descriptions with figures, identification key, synonymy, and distribution maps are provided. The most significant diagnostic characters are: shell shape and colour, umbilicus shape and size, durability of hairs, penis/epiphallus length ratio, flagellum/epiphallus length ratio, number and arrangement of mucous glands, length and location of dart sacs. Three names are synonymised: T. plebeius, T. concinnus and T. hispidus. Phylogenetic analysis yielded 96 equally parsimonious trees; the strict consensus procedure resulted in an incompletely resolved cladogram, with two distinct monophyletic groups of species: the villosus group including villosus, czarnohoricus, unidentatus and bielzi, and the striolatus group, with striolatus, graminicolus, montanus, caelatus, hispidus, suberectus, edentulus, bakowskii, luridus, filicinus and leucozonus. These two groups and erjaveci, biconicus, villosulus, clandestinus, lubomirskii and piccardi, form a phylogenetic bush. The monophyletic groups appearing in the cladogram are not compatible with any of the earlier proposed divisions. Most members of Trochulus inhabit the Alps and the Carpathians. The only widely distributed species is T. hispidus. The second most widespread species is T. striolatus. The remaining species are endemics with limited ranges. The number of species within particular parts of the range points to the Alpine-Carpathian area as the diversity centre of the genus.

The taxonomic status of Trochulus phorochaetius and its phylogenetic relationships to Trochulus plebeius and Trochulus hispidus were evaluated based on molecular, morphological, and genital anatomy data. The canonical discriminant analysis (CDA) of shell morphology allowed the clear differentiation between these three nominal species, whereas the genitalia revealed their high similarity. Analyses of cytochrome c oxidase subunit I (COI) sequences were not always congruent with the differentiation between these three species by shell characters. None of them formed a monophyletic group covering all its sequences. Instead, many sequences obtained from individuals classified to the same morphospecies, and/or usually collected from the same region or country, created highly supported separate clades and delimited clusters. Three distinct clades containing sequences of two morphospecies originating from the same country were identified in molecular phylogenetic and species delimitation studies: (1) T. plebeius + T. hispidus from Great Britain; (2) T. plebeius + T. hispidus from Poland; and (3) T. phorochaetius + T. hispidus from France. In the latter case some of the sequences were even identical. Their genetic similarity could indicate the ability to hybridize, which may be evidenced by the lack of major differences in their reproductive system. The assignment of distinctive morphospecies, and thus existing taxonomic names, to genetically defined evolutionary lineages is premature and arbitrary to some extent at this stage. © 2013 The Linnean Society of London

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For the first time the life cycle of the common land snail Trochulus hispidus was completely described in Central Europe (Poland). This is a semelparous species predominantly with an annual life cycle and the reproductive period lasting from April till October. The first young snails hatch in spring, grow rapidly in summer and reach ca. 4 whorls until winter. In spring of the next year they mature and reproduce. After that they die. There is hardly any growth from late autumn till early spring. The average proportional growth rate is ca. 0.3 whorl/month in the wild. The fastest growth is present in the youngest snails and then gradually decreases over the course of their age. Laboratory and field observations allowed for establishing the following life cycle parameters: eggs calcified, almost spherical, ca. 1.5 mm, laid in spring and summer in batches of between 1 and 47. Time to hatching is 6-24 days, hatching is asynchronous; newly-hatched snails have approximately 1.5 whorls. Analysis of food preferences revealed, that T. hispidus tends to restrict its diet during the life. Generally the youngest snails equally consumed leaves of all four tree species offered (Fraxinus excelsior, Acer pseudoplatanus, Tilia cordata and A. platanoides) whereas adults preferred F. excelsior over A. pseudoplatanus and A. platanoides.

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Monacha claustralis (Rossmässler) and M. cartusiana (O. F. Müller) are frequently confused due to their great shell similarity. The only reliable identification of these species can be based on the genital and molecular characters. Based on sequences of two mitochondrial gene (COI and 16SrDNA) fragments we identified the distribution of these species. M. claustralis was recognised as a species spreading northwards from its typical Turkish and Greek localities since its occurrence was discovered in Montenegro and Bosnia-Herzegovina on the basis of anatomical and molecular evidence. Moreover, its several new localities in Poland are reported. The occurrence of M. cartusiana is for the first time molecularly confirmed in Germany, Slovakia, Austria, Croatia and Kosovo, and some new localities are also reported from Poland, Hungary, and Bosnia-Herzegovina.

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Geographical isolation, selection and genetic drift can cause the geographical diversification of populations and lead to speciation. Land snail species in the genus Trochulus show overlaps in geographical ranges as well as in morphology, but genetic data do not always support the species-level taxonomy based on morphological characters. Such a group offers an excellent opportunity to explore the processes involved. We have addressed the problem by determining the status of the restricted endemic T. graminicola within the larger context of Trochulus taxonomy. We used an integrated approach based on morphological features, ecological preferences and two molecular markers: mitochondrial COI sequences and microsatellites. Comparison of these results demonstrated: (i) conchological distinction of T. striolatus and T. sericeus; (ii) anatomical, ecological and genetic differentiation of T. graminicola and (iii) concordance between morphological characters and mtDNA markers in T. striolatus. Moreover, our data showed an intricate evolutionary history within the genus Trochulus, which can be best explained by: (i) recent or ongoing gene flow between taxa or (ii) their large ancestral polymorphism. Both of these hypotheses suggest that diversification within this group of snails has occurred relatively recently. The mismatches between species defined on morphology and on molecular genetics indicate the complexity of the processes involved in the diversification of this genus.