Based on published records and original data from recent research, a list is presented of the leeches (Hirudinea) of Montenegro. It includes 29 species and subspecies in 13 genera and 5 families. Numerous new records are reported; Glossiphonia paludosa (Carena, 1824), Helobdella stagnalis (Linnaeus, 1758), Alboglossiphonis hyalina (O. F. Müller, 1774), Alboglossiphonia striata (Apáthy, 1888), Piscicola pawlowskii (Sket, 1968), Piscicola respirans Troschel, 1850, Hirudo verbana Carena, 1820, Erpobdella nigricollis (Brandes, 1900) and Erpobdella vilnensis (Liskiewicz, 1925), are reported for the first time for Montenegro. The characteristics of the leeches fauna in the treated area are briefly outlined.

The bloodfeeding leech genus Placobdella is dominated by North American diversity, with only a single nominal species known from Central America and one from the Palearctic region. This is likely due to considerable underestimation of Palearctic biodiversity, but investigations into potential hidden diversity are lacking. To shed light on this, the present study introduces new data for specimens initially identified as Placobdella costata from Ukraine (close to the type locality),

Glossiphoniid leeches are a diverse group and sometimes abundant elements of the aquatic fauna inhabiting various types of freshwater habitats. In this study, we sampled leeches of the genus Glossiphonia from the Western Balkan in order to test the suitability of the mitochondrial cytochrome c oxidase subunit 1 (COI) marker sequence for species delimitation. Morphological analysis revealed the presence of four taxa, G. complanata with two subspecies, G. c. complanata and G. c. maculosa, the latter an endemic of Ohrid Lake, G. nebulosa and endemic G. balcanica. In total, 29 new barcodes of Glossiphonia were sequenced in the course of this study and compared with the available molecular dataset of the latter genus from GenBank/BOLD databases. The applied ASAP distance-based species delimitation method for the analysed dataset revealed an interspecific threshold between 4-8% K2P distance as suitable for species identification purposes of the Western Balkan Glossiphonia species. Our study revealed that morphologically identified taxa as G. nebulosa and G. concolor each consists of more than one clearly different phylogenetic clade. This study contributes to a better knowledge of the taxonomy of glossiphoniid leeches and emphasises future work on the revision of this genus using a standard molecular COI marker in species identification.

The aim of this study was to reveal faunistic and diversity patterns and to assess the effects of environmental factors on the differentiation of leech communities. This study covers investigations of 82 karst springs in Montenegro from 2009–2017. The communities were analyzed in respect to five wellspring types – caves, sublacustrine, limnocrene, rheo-limnocrene and rheocrene. The percentage of substrate types and aquatic vegetation cover was recorded alongside water parameters. In total, 18 leech species were identified, of which two were recently described as new species for science (Dina minuoculata Grosser, Moritz and Pešić, 2007 and Glossiphonia balcanica Grosser and Pešić, 2016). K-means clustering was used to classify leech assemblages into three homogenous groups. The patterns of leech communities and the components of both alpha and beta diversity were examined in identified groups of assemblages. The significance of environmental factors and the impact of selected factors were assessed through forward selection analysis, CCA and RDA. Our results indicate that the type of spring and the environmental variables, as well as the combination of biotic and abiotic factors in a microhabitat dictate the distribution of leeches.

Two new leech species (Hirudinida) representing the families Glossiphoniidae (Glossiphonia balcanica n. sp.) and Erpobdellidae (Dina prokletijaca n. sp.) are described. The populations from Montenegro assigned by Utevsky et al. (2013) and Grosser et al. (2015) to Glossiphonia nebulosa Kalbe, 1964 represent an new species, here described as G. balcanica n. sp. The new species can be easily be separated from Glossiphonia nebulosa by the reduction of the papillae. Dina prokletijaca n. sp. closely resembles D. dinarica Sket, 1968 and D. montana Sket, 1968 from which can be distinguished in the combination of the small and stocky body, dorsal surface with two wide and dark paramedian longitudinal stripes and ovisacs reaching the fourth somite after the female genital pore, and curled in their entire course. A key to the species of Glossiphonia Johnson, 1816 and Dina R. Blanchard, 1892 from the Western Balkans is presented.