A further northward expansion of the invasive land snails Monacha cartusiana and M. Fruticola (Stylommatophora: Hygromiidae) in Eastern Europe

Land snails of the genus Monacha are shown to have expanded widely northward in Eastern Europe during the last decade. Previously their ranges there were limited to Southern Ukraine, Caucasus and several isolated colonies in Western Ukraine. Our new reports cover all parts of Ukraine, as well as some regions of southern Belarus and western Russia. We have sampled 5 large colonies of M. cartusiana in Kyiv region (Central Ukraine) and one in Kharkiv city (northeastern Ukraine), as well as two colonies of M. fruticola in Kyiv city. We also report 72 new records of the subgenus Monacha (M. cf. cartusiana) in Eastern Europe, based mostly on the photographs from citizen science databases (iNaturalist, UkrBIN). The distribution of M. cartusiana around Kyiv city has shown an especially rapid and wide expansion; we report on 36 colonies, some of which are very abundant and cover several tens of hectares each, while the oldest known record of Monacha in this region is only from 2017. Origin, expansion and perspectives of the Monacha species in Eastern Europe are discussed.

The complete mitochondrial genome of the terrestrial snail Monachacartusiana (O.F. Müller, 1774) (Gastropoda, Eupulmonata, Hygromiidae)

The mitochondrial genome of Monachacartusiana is the first complete mitochondrial sequence described for the pulmonate snail genus Monacha and for the family Hygromiidae. The identified mitogenome has a length of 13,894 bp and encodes 13 proteins, 22 tRNAs, and two rRNAs. A phylogenetic analysis of available mitogenomes from representatives of helicoid families shows a sister group relationship of Hygromiidae and Geomitridae, which have been recently recognised as separate families.

Redescription of Monacha pantanellii (De Stefani, 1879), a species endemic to the central Apennines, Italy (Gastropoda, Eupulmonata, Hygromiidae) by an integrative molecular and morphological approach

Specimens obtained from ten populations of a Monacha species from the central Apennines were compared with six molecular lineages of Monacha cantiana s. l. (CAN-1, CAN-2, CAN-3, CAN-4, CAN-5, CAN-6) and two other Monacha species (M. cartusiana and M. parumcincta), treated as outgroup, by molecular (nucleotide sequences of two mitochondrial COI and 16S rDNA as well as two nuclear ITS2 and H3 gene fragments) and morphological (shell and genital anatomy) analysis. The results strongly suggest that these populations represent a separate species for which two names are available: the older Helix pantanellii De Stefani, 1879 and the junior M. ruffoi Giusti, 1973. The nucleotide sequences created well separated clades on each phylogenetic tree. Genital anatomy included several distinctive features concerning vaginal appendix, penis, penial papilla and flagellum; instead, shell characters only enabled them to be distinguished from M. cartusiana and M. parumcincta. Remarkably, populations of M. pantanellii show high morphological variability. Shell variability mainly concerns size, some populations having very small dimensions. Genital variability shows a more intricate pattern of all anatomical parts, being higher as regards the vagina and vaginal appendix. Despite this morphological variability, the K2P distance range of COI sequences between populations is narrow (0.2-4.5%), if we consider all but three of the 53 sequences obtained. This research confirmed that the species of Monacha and their molecularly distinguished lineages can only occasionally be recognised morphologically and that they have significant inter- and intra-population variability. The possibility of using an overall approach, including shell, genital and molecular evidence, was taken in order to establish a reliable taxonomic setting.