taxonID	type	description	language	source
C33FF42BCD0CFF9CC682DB10FD0DF9CA.taxon	description	Order Hirudinida Siddall, Apakupakul, Burreson, Coates, Erséus, Gelder, Källersjö & Trapido- Rosenthal, 2001	en	Bolotov, Ivan N., Eliseeva, Tatyana A., Marin, Ivan N., Palatov, Dmitry M., Nguyen, Trung Duc, Kropotin, Alexander V., Gofarov, Mikhail Y., Kondakov, Alexander V. (2025): Arthropod-associated leeches (Annelida: Hirudinida) of the World: Diversity, taxonomic reappraisal, ecological classification of host associations, and convergent evolution. Ecologica Montenegrina 89: 38-86, DOI: 10.37828/em.2025.89.3, URL: https://doi.org/10.37828/em.2025.89.3
C33FF42BCD0CFF9CC682DB10FD0DF9CA.taxon	description	Subfamily Glossiphoniinae Vaillant, 1890	en	Bolotov, Ivan N., Eliseeva, Tatyana A., Marin, Ivan N., Palatov, Dmitry M., Nguyen, Trung Duc, Kropotin, Alexander V., Gofarov, Mikhail Y., Kondakov, Alexander V. (2025): Arthropod-associated leeches (Annelida: Hirudinida) of the World: Diversity, taxonomic reappraisal, ecological classification of host associations, and convergent evolution. Ecologica Montenegrina 89: 38-86, DOI: 10.37828/em.2025.89.3, URL: https://doi.org/10.37828/em.2025.89.3
C33FF42BCD0CFF9FC682D8C1FD2BFC4E.taxon	description	Figure S 2	en	Bolotov, Ivan N., Eliseeva, Tatyana A., Marin, Ivan N., Palatov, Dmitry M., Nguyen, Trung Duc, Kropotin, Alexander V., Gofarov, Mikhail Y., Kondakov, Alexander V. (2025): Arthropod-associated leeches (Annelida: Hirudinida) of the World: Diversity, taxonomic reappraisal, ecological classification of host associations, and convergent evolution. Ecologica Montenegrina 89: 38-86, DOI: 10.37828/em.2025.89.3, URL: https://doi.org/10.37828/em.2025.89.3
C33FF42BCD0CFF9FC682D8C1FD2BFC4E.taxon	type_taxon	Type species. Paraclepsis praedatrix Harding, 1924 (subsequent designation by Soós, 1969).	en	Bolotov, Ivan N., Eliseeva, Tatyana A., Marin, Ivan N., Palatov, Dmitry M., Nguyen, Trung Duc, Kropotin, Alexander V., Gofarov, Mikhail Y., Kondakov, Alexander V. (2025): Arthropod-associated leeches (Annelida: Hirudinida) of the World: Diversity, taxonomic reappraisal, ecological classification of host associations, and convergent evolution. Ecologica Montenegrina 89: 38-86, DOI: 10.37828/em.2025.89.3, URL: https://doi.org/10.37828/em.2025.89.3
C33FF42BCD0CFF9FC682D8C1FD2BFC4E.taxon	diagnosis	Differential diagnosis. Small leeches (length up to 15.5 mm; Harding 1924); three pairs of eyespots on III, IV a 1 and V a 2 (second and third pairs of eyespots are separated by two annuli); body with 70 - 73 annuli, mid-body somites triannulate; dorsum with four rows of ovate shallow papillae; mouth pore is subterminal (near the rim of the anterior sucker); two pairs of compact salivary glands; esophagus with broad, bag-like pharingeal bulb; seven pairs of crop caeca; six pairs of testisacs; gonopores separated by two annuli: male gonopore on XI a 3 / XII a 1, female gonopore on XII a 2 / XII a 3; posterior sucker is small, circular, ventrally directed. Phylogenetically, this genus represents a separate, distant group that is sister to the clade Orientobdelloides + Batracobdella.	en	Bolotov, Ivan N., Eliseeva, Tatyana A., Marin, Ivan N., Palatov, Dmitry M., Nguyen, Trung Duc, Kropotin, Alexander V., Gofarov, Mikhail Y., Kondakov, Alexander V. (2025): Arthropod-associated leeches (Annelida: Hirudinida) of the World: Diversity, taxonomic reappraisal, ecological classification of host associations, and convergent evolution. Ecologica Montenegrina 89: 38-86, DOI: 10.37828/em.2025.89.3, URL: https://doi.org/10.37828/em.2025.89.3
C33FF42BCD0CFF9FC682D8C1FD2BFC4E.taxon	distribution	Distribution. India, Sri Lanka, Thailand, Vietnam, and South-East China (Table 3). List of species. Paraclepsis cancricola (Oka, 1928) [South-East China]; Pa. dongnaiensis sp. nov. [Thailand and Vietnam]; Pa. ceylanica (Harding, 1909) [= Pa. vulnifera Harding, 1924 syn. nov.; = Pa. praedatrix Harding, 1924 syn. nov.; India and Sri Lanka] (Table 3).	en	Bolotov, Ivan N., Eliseeva, Tatyana A., Marin, Ivan N., Palatov, Dmitry M., Nguyen, Trung Duc, Kropotin, Alexander V., Gofarov, Mikhail Y., Kondakov, Alexander V. (2025): Arthropod-associated leeches (Annelida: Hirudinida) of the World: Diversity, taxonomic reappraisal, ecological classification of host associations, and convergent evolution. Ecologica Montenegrina 89: 38-86, DOI: 10.37828/em.2025.89.3, URL: https://doi.org/10.37828/em.2025.89.3
C33FF42BCD0CFF9FC682D8C1FD2BFC4E.taxon	biology_ecology	Hosts. Historically, freshwater turtles (Trionychidae) and crabs (Gecarcinucidae) were considered hosts for leeches in this genus (Harding 1924; Harding and Moore 1927; Soós 1969). However, there are reliable records from frogs (Dicroglossidae) (Kaburaki 1921; Chandra and Mukharjee 1973) and from the buccal cavity of an aquatic snake (Colubridae) (Chandra and Saha 1967). In our opinion, relationships of these leeches with turtles and crabs may be regarded as phoretic / dwelling biotic interactions, whereas frogs and the snake may serve as primary hosts (Table 3). It is well known that various leech species (both parasitic and predatory taxa) may use turtles as phoretic hosts (e. g., Oosthuizen 1991; Marrone et al. 2016; Perera et al. 2019; Watermolen 2021).	en	Bolotov, Ivan N., Eliseeva, Tatyana A., Marin, Ivan N., Palatov, Dmitry M., Nguyen, Trung Duc, Kropotin, Alexander V., Gofarov, Mikhail Y., Kondakov, Alexander V. (2025): Arthropod-associated leeches (Annelida: Hirudinida) of the World: Diversity, taxonomic reappraisal, ecological classification of host associations, and convergent evolution. Ecologica Montenegrina 89: 38-86, DOI: 10.37828/em.2025.89.3, URL: https://doi.org/10.37828/em.2025.89.3
C33FF42BCD0CFF9FC682D8C1FD2BFC4E.taxon	discussion	Comments. Our concept of Paraclepsis is largely based on the morphology-based revision of Sawyer (1986), who transferred the nominal taxa Placobdella ceylanica and Batracobdella cancricola to this genus. This author also assumed that Paraclepsis vulnifera may represent an intraspecific form of Pa. praedatrix but did not formally synonymize these nominal species (Sawyer 1986: 764). Three nominal species from India and Sri Lanka, that is, Paraclepsis ceylanica, Pa. vulnifera, and Pa. praedatrix cannot be delineated using the morphological and anatomical diagnostic characters presented in their original descriptions and subsequent re-descriptions (Figure S 2; Harding 1909; Kaburaki 1921; Harding 1924; Harding and Moore 1927). For instance, Pa. vulnifera is similar to Pa. praedatrix but differs from it by a few minor traits as follows: (1) the head region is continuous with the body and is not separated from it by a posterior constriction; (2) smaller number of annuli (70 vs. 73); and (3) the lack of large vesiculae seminales (Harding 1924; Harding and Moore 1927). It was also noted that the condition of the type series of Pa. vulnifera was unfavorable for observation of the papillae and coloration (Harding 1924). In our opinion, the shape of the head region cannot be used as a reliable diagnostic trait in leeches because this feature may vary depending on the condition of specimens and the methods of their fixation (see the series of specimens on Figure 8 A-F). The precise counting of the total number of annuli can be difficult in contracted specimens, while the development of vesiculae seminales may differ depending on the degree of maturity of individuals. Therefore, we agree with Sawyer’s (1986) assumption that the two nominal species are conspecific. Moreover, they are morphologically indistinguishable from an older nominal species, Paraclepsis ceylanica, and are considered its synonyms. Here, we also confirm the placement of Paraclepsis cancricola, a crab-associated leech from South-East China, in this genus based on the phylogenetic evidence (see Figure 7). Morphologically, this leech fully aligns with the generic diagnosis and has three pairs of eyespots with the two posterior pairs separated by two annuli, body with 70 annuli, seven pairs of crop caeca, esophagus with an esophagial bulb, six pairs of testisacs, and two annuli between gonopores (Yang 1986). Two nominal species in the genus Paraclepsis were recently described from India: (1) Paraclepsis gardensi Mandal, 2004 [holotype: ZSI An 2768 / 1; type locality: King Lake, 22.5598 ° N, 88.2879 ° E, Botanical Garden, Shibpur, Howrah, West Bengal, India; host: unknown] (Mandal 2004); (2) Paraclepsis jorapariensis Mandal, 2015 [holotype: ZSI An 3702 / 1; type locality: Jorapari, 24.1 ° N, 86.3 ° E, Giridih District, Jharkhand, India; host: unknown] (Mandal 2015). Although the DNA sequences of these nominal species are not available, they cannot be considered representatives of the original genus based on morphological criteria. In particular, Paraclepsis gardensi is characterized by (1) three pairs of eyespots with the two posterior pairs separated by one annulus, and (2) the position of the mouth pore in the anterior half of the oral sucker (Figure S 3). There is a peculiar subgroup in the genus Hemiclepsis Vejdovsky, 1884, the representatives of which have three pairs of eyespots in this kind of arrangement, as well as a similar position of the mouth pore. This subgroup contains three species: Hemiclepsis bhatiai Baugh, 1960 [Bihar and Jammu and Kashmir, India], Hm. erhaiensis Yang, 1981 [Erhai, Dianchi and Chenghai lakes, Yunnan, China], and Hm. viridis Chelladurai, 1934 [Kerala and Tamil Nadu, India] (Chelladurai 1934; Baugh, 1960 a; Yang 1996; Bolotov et al. 2019). The second pair of eyespots is the largest in Hemiclepsis bhatiai and Paraclepsis gardensi. However, the latter species can be distinguished from Hemiclepsis bhatiai by having 18 longitudinal greenish stripes on the dorsum (vs. four longitudinal series of brown spots). In turn, dorsum of Hemiclepsis viridis bears 15 to 25 longitudinal green lines but in this nominal species the third pair of eyespots is the largest (Chelladurai 1934). It is known that the size of eyespots in the Glossiphoniidae is rather variable (Soós 1969; but see Eliseeva et al. 2024 for exception). Moreover, a paratype of Paraclepsis gardensi has the second and third pair of eyespots of similar size (Figure S 3). Therefore, we propose the new synonymy as follows: Hemiclepsis viridis Chelladurai, 1934 [= Paraclepsis gardensi Mandal, 2004 syn. nov.].	en	Bolotov, Ivan N., Eliseeva, Tatyana A., Marin, Ivan N., Palatov, Dmitry M., Nguyen, Trung Duc, Kropotin, Alexander V., Gofarov, Mikhail Y., Kondakov, Alexander V. (2025): Arthropod-associated leeches (Annelida: Hirudinida) of the World: Diversity, taxonomic reappraisal, ecological classification of host associations, and convergent evolution. Ecologica Montenegrina 89: 38-86, DOI: 10.37828/em.2025.89.3, URL: https://doi.org/10.37828/em.2025.89.3
C33FF42BCD0FFF95C682DA7EFDA5FCB7.taxon	description	https: // zoobank. org / urn: lsid: zoobank. org: act: E 9738 BC 4 - FA 5 F- 413 B-A 3 CF-EDC 60324 AD 9 D	en	Bolotov, Ivan N., Eliseeva, Tatyana A., Marin, Ivan N., Palatov, Dmitry M., Nguyen, Trung Duc, Kropotin, Alexander V., Gofarov, Mikhail Y., Kondakov, Alexander V. (2025): Arthropod-associated leeches (Annelida: Hirudinida) of the World: Diversity, taxonomic reappraisal, ecological classification of host associations, and convergent evolution. Ecologica Montenegrina 89: 38-86, DOI: 10.37828/em.2025.89.3, URL: https://doi.org/10.37828/em.2025.89.3
C33FF42BCD0FFF95C682DA7EFDA5FCB7.taxon	materials_examined	Holotype. RMBH Hir _ 1190 - H; VIETNAM: Cát Tiên National Park, 11.4369 ° N, 107.4230 ° E, altitude 130 m, Đ ồng Nai River basin, Đ ồng Nai Province, temporary forest pools, on the carapace of freshwater crab Somanniathelphusa triangularis Đăng & Ð ỗ, 2005 (Decapoda: Gecarcinucidae), October 2024, Ivan N. Marin leg. (Figure 8 A). Paratypes (n = 16). VIETNAM: the type locality, the same habitat, host, collecting date and collector – 14 specimens (lot RMBH Hir _ 1190) (Figure 8 B-D). VIETNAM: underside large stones in spring at the entrance of a mountain massif, 3.5 km SW of Tri Tôn city, 10.3959 ° N, 104.9828 ° E, altitude 38 m, Tri Tôn Rural District, An Giang Province, Mekong Delta Region, 11 November 2023, Dmitry M. Palatov leg. – 2 specimens (lot RMBH Hir _ 1137) (Figure 8 E-F).	en	Bolotov, Ivan N., Eliseeva, Tatyana A., Marin, Ivan N., Palatov, Dmitry M., Nguyen, Trung Duc, Kropotin, Alexander V., Gofarov, Mikhail Y., Kondakov, Alexander V. (2025): Arthropod-associated leeches (Annelida: Hirudinida) of the World: Diversity, taxonomic reappraisal, ecological classification of host associations, and convergent evolution. Ecologica Montenegrina 89: 38-86, DOI: 10.37828/em.2025.89.3, URL: https://doi.org/10.37828/em.2025.89.3
C33FF42BCD0FFF95C682DA7EFDA5FCB7.taxon	etymology	Etymology. This species is named after the Đ ồng Nai River, in the drainage of which its type locality is situated.	en	Bolotov, Ivan N., Eliseeva, Tatyana A., Marin, Ivan N., Palatov, Dmitry M., Nguyen, Trung Duc, Kropotin, Alexander V., Gofarov, Mikhail Y., Kondakov, Alexander V. (2025): Arthropod-associated leeches (Annelida: Hirudinida) of the World: Diversity, taxonomic reappraisal, ecological classification of host associations, and convergent evolution. Ecologica Montenegrina 89: 38-86, DOI: 10.37828/em.2025.89.3, URL: https://doi.org/10.37828/em.2025.89.3
C33FF42BCD0FFF95C682DA7EFDA5FCB7.taxon	diagnosis	Differential diagnosis. Small leech with leaf-shaped body; three pairs of eyespots in the genuscharacteristic arrangement; four rows of ovate shallow dorsal papillae of moderate size (outer paramedian and outer paramarginal series); two annuli between the male (XI a 3 / XII a 1) and female (XII a 2 / a 3) genital pores; esophagus with a broad, bag-like pharingeal bulb; two pairs of compact salivary glands; 7 pairs of crop caeca. The new species differs from Paraclepsis ceylanica and Pa. cancricola by having simple crop caeca (vs bilobate). Molecular diagnosis. The mean uncorrected COI p-distance between the new species and Pa. cancricola is 11.2 ± 0.1 %. The GenBank acc. numbers of reference DNA sequences of the new species (COI and 18 S rRNA) are given in Table S 1.	en	Bolotov, Ivan N., Eliseeva, Tatyana A., Marin, Ivan N., Palatov, Dmitry M., Nguyen, Trung Duc, Kropotin, Alexander V., Gofarov, Mikhail Y., Kondakov, Alexander V. (2025): Arthropod-associated leeches (Annelida: Hirudinida) of the World: Diversity, taxonomic reappraisal, ecological classification of host associations, and convergent evolution. Ecologica Montenegrina 89: 38-86, DOI: 10.37828/em.2025.89.3, URL: https://doi.org/10.37828/em.2025.89.3
C33FF42BCD0FFF95C682DA7EFDA5FCB7.taxon	description	Description. Small leech (body length up to 11.6 mm). The measurements of the holotype and paratypes are presented in Dataset S 4 on figshare (Bolotov et al. 2025 c). Body is broad, leaf-shaped, elongate-ovate (Figure 8 A-F). Dorsum with four rows of ovate shallow papillae of moderate size on annulus a 2 (outer paramedian and outer paramarginal series). Posterior sucker is small, circular (maximum diameter of 1.5 mm), and ventrally directed. Proboscis pore at the rim of anterior sucker. Coloration of living animals: dorsum is translucent, light-brown, sometimes with sparse green chromatophores; a median series of 7 - 8 yellow spots of irregular shape, which are larger at the posterior part of the body; four additional series of small yellow round spots at the outer paramarginal and marginal positions; some specimens have dorsum with multiple brown longitudinal lines and a marginal series of light round spots; posterior sucker is brown with light radial stripes (Figures 9 A-C, 10 A-B). It largely agrees with that of the carapace of crab hosts and, at first glance, could be considered a camouflage (cryptic) coloration (Figures 9 A-C). Coloration of ethanol-preserved animals: dorsum is dark brown, sometimes with numerous darker longitudinal stripes; three longitudinal rows of yellow spots at marginal (large ovate spots at a 3), outer paramarginal (smaller ovate spots at a 2) and outer paramedian (minute dots at a 2) position; the anterior eyespots-bearing part with light margin and large light spot around the third pair of eyespots. Some specimens have yellow dorsum with multiple longitudinal brown lines; median line is broad and broken, consisting of several parts, separated by ground yellow color; other lines are narrow, continuous (Figure 8 A-F). Three pairs of circular or cup-shaped eyespots are situated on III, IV a 1 and V a 2 (second and third pairs of eyespots are separated by two annuli) and arranged to a triangle with narrow base: eyespots of the first pair are small, joined to a single spot and usually connected with the second pair; eyespots of the second pair are circular, situated close to each other or connected; eyespots of the third pair are circular, separate (Figure 10 C-F). Venter is smooth, yellowish to whitish, sometimes with sparse brown to dark green chromatophores and a white patch around the gonopores. Total number of annuli: 70. Somites I-III uniannulate, IV biannulate, V – XXIV triannulate, XXV-XXVI biannulate, XXVII uniannulate. The male and female genital pores are separated by two annuli and are located in furrows XI a 3 / XII a 1 and XII a 2 / a 3, respectively (Figure 10 G). Reproductive system: six pairs of large, ovate testisacs intersegmentally from XIV / XV to XIX / XX; atrium spherical, the atrial cornua massive, twisted anteriorly; paired ejaculatory ducts long, extending to XVII; paired ovisacs moderately long, arranged as loops (Figure 11 A-D). Digestive system: proboscis sheath short, of moderate size; esophagus with a broad, bag-like pharingeal bulb; salivary glands compact, two pairs; crop with seven pairs of crop caeca: 1 st – 6 th simple, elongate finger-like, 7 th pair (posterior caeca) with four blind processes; intestine with four simple processes.	en	Bolotov, Ivan N., Eliseeva, Tatyana A., Marin, Ivan N., Palatov, Dmitry M., Nguyen, Trung Duc, Kropotin, Alexander V., Gofarov, Mikhail Y., Kondakov, Alexander V. (2025): Arthropod-associated leeches (Annelida: Hirudinida) of the World: Diversity, taxonomic reappraisal, ecological classification of host associations, and convergent evolution. Ecologica Montenegrina 89: 38-86, DOI: 10.37828/em.2025.89.3, URL: https://doi.org/10.37828/em.2025.89.3
C33FF42BCD0FFF95C682DA7EFDA5FCB7.taxon	distribution	Distribution. Thailand (Moore 1935) and Southern Vietnam (Figure 12). Phoretic / dwelling host. In the type locality, specimens of the new species were collected on the carapace of the freshwater crab Somanniathelphusa triangularis Đăng & Ð ỗ, 2005 (Gecarcinucidae). In Thailand, it was collected from the gill chamber of another crab species in this genus, S. sinensis (H. Milne Edwards, 1853) (Moore 1935). Primary host. The COI sequences of iDNA that was taken from the gut content of three paratypes reveal that they suck blood of the frog species Hoplobatrachus chinensis (Osbeck, 1765) (Dicroglossidae). The accession numbers of the host COI sequences are as follows: PV 132093 (paratype RMBH Hir _ 1137 - 1); PV 132094 (paratype RMBH Hir _ 1190 DNA- 2); and PV 132095 (paratype RMBH Hir _ 1190 DNA- 3) (Bolotov et al. 2025 c: Dataset S 4).	en	Bolotov, Ivan N., Eliseeva, Tatyana A., Marin, Ivan N., Palatov, Dmitry M., Nguyen, Trung Duc, Kropotin, Alexander V., Gofarov, Mikhail Y., Kondakov, Alexander V. (2025): Arthropod-associated leeches (Annelida: Hirudinida) of the World: Diversity, taxonomic reappraisal, ecological classification of host associations, and convergent evolution. Ecologica Montenegrina 89: 38-86, DOI: 10.37828/em.2025.89.3, URL: https://doi.org/10.37828/em.2025.89.3
C33FF42BCD0FFF95C682DA7EFDA5FCB7.taxon	description	Habitats. The type series was collected from temporary forest pools (on crabs) and a spring (free-living, beneath stones). The crop of two available specimens (sample RMBH Hir _ 1137) from a spring is completely filled with frog host blood (Figure 8 E-F), while that of leeches from crabs (sample RMBH Hir _ 1190) is less filled with the same content (Figure 8 A-D). We assume that amphibious crabs may serve as transport hosts and shelter for dispersal through land barriers between separate water bodies, especially during dry season (see Discussion for detail). Biogeographical notes. Available samples of the new species comprises of two distant genetic lineages with an uncorrected COI p-distance of 3.7 %. The first lineage was discovered in the Cát Tiên National Park (the type locality of the new species) and most likely inhabits the Đ ồng Nai River basin. The latter basin is situated east of the Mekong Delta (see Figure 12). The second lineage was recorded from a spring in An Giang, belonging to the Mekong River basin and situated west of the Mekong Delta. We were unable to find any diagnostic differences between the two lineages by means of morphological and anatomical analyses, and these samples are here considered conspecific. The relatively large genetic distance between these populations could be explained by several reasons. First, the deep, turbulent mainstream of the Mekong River itself may serve as an effective barrier to dispersal of the crabs and the leeches using them as transport hosts (e. g., Gascon et al. 2000; Zhang et al. 2010; Wang et al. 2015; Yuan et al. 2016; De Castro Godinho and Silva 2018; Brunke et al. 2019). It is known that the Somanniathelphusa host crabs (Gecarcinucidae) are rather amphibious than fully aquatic (Yeo and Nguyen 1999; Shih et al. 2007). They dwell in shallow water bodies such as forest pools, streams, and flooded paddy fields. The leeches we found were collected from crabs that lived in shallow forest pools or small streams, whereas these leeches were never recorded on crabs collected from the beds of the Đ ồng Nai and Mekong rivers or from paddy fields in the Mekong Delta. These patterns may explain the recent lack of gene flow between populations of leeches. Second, paleogeographic events such as periodical marine transgressions and regressions might have influence the past connectivity of freshwater leech populations in the southern edge of the the Indochina Peninsula (Gupta 2009; Tjallingii et al. 2010). There were large fluctuations in the sea level in the Miocene, ranging between - 300 and + 180 m (Miller et al. 2005). Marine regressions connected the Mekong with other basins such as Đ ồng Nai and Chao Phraya (Morley 2012; Morley and Morley 2013; Arifin et al. 2022; Giao et al. 2023). In turn, massive marine transgressions led to the flooding of the Mekong Delta with saline waters, crossing the modern borders of Cambodia and reaching the Tonle Sap Lake (Penny 2006; Miller et al. 2005). In the Pleistocene, the eustatic sea level fluctuations reached smaller magnitudes from - 120 to + 50 meters (Haq et al. 1987; Woodruff 2003; Miller et al. 2005). The deglacial sea-level rise and the maximum flooding period (19 – 8 and 8 – 6 Kya, respectively) reduced the lower part of the Mekong Delta (Tjallingii et al. 2010; Thanh et al. 2021) and likely divided the basins of the Mekong and Đ ồng Nai rivers. The events, mentioned above, might have contributed to the isolation of freshwater animal populations in the region (De Bruyn et al. 2013; Sholihah et al. 2021; Delrieu-Trottin et al. 2025).	en	Bolotov, Ivan N., Eliseeva, Tatyana A., Marin, Ivan N., Palatov, Dmitry M., Nguyen, Trung Duc, Kropotin, Alexander V., Gofarov, Mikhail Y., Kondakov, Alexander V. (2025): Arthropod-associated leeches (Annelida: Hirudinida) of the World: Diversity, taxonomic reappraisal, ecological classification of host associations, and convergent evolution. Ecologica Montenegrina 89: 38-86, DOI: 10.37828/em.2025.89.3, URL: https://doi.org/10.37828/em.2025.89.3
C33FF42BCD05FF96C682DD28FCB6FD52.taxon	description	Figure S 4	en	Bolotov, Ivan N., Eliseeva, Tatyana A., Marin, Ivan N., Palatov, Dmitry M., Nguyen, Trung Duc, Kropotin, Alexander V., Gofarov, Mikhail Y., Kondakov, Alexander V. (2025): Arthropod-associated leeches (Annelida: Hirudinida) of the World: Diversity, taxonomic reappraisal, ecological classification of host associations, and convergent evolution. Ecologica Montenegrina 89: 38-86, DOI: 10.37828/em.2025.89.3, URL: https://doi.org/10.37828/em.2025.89.3
C33FF42BCD05FF96C682DD28FCB6FD52.taxon	type_taxon	Type species. Helobdella tricarinata Blanchard, 1897 (by original designation).	en	Bolotov, Ivan N., Eliseeva, Tatyana A., Marin, Ivan N., Palatov, Dmitry M., Nguyen, Trung Duc, Kropotin, Alexander V., Gofarov, Mikhail Y., Kondakov, Alexander V. (2025): Arthropod-associated leeches (Annelida: Hirudinida) of the World: Diversity, taxonomic reappraisal, ecological classification of host associations, and convergent evolution. Ecologica Montenegrina 89: 38-86, DOI: 10.37828/em.2025.89.3, URL: https://doi.org/10.37828/em.2025.89.3
C33FF42BCD05FF96C682DD28FCB6FD52.taxon	diagnosis	Differential diagnosis. Small to medium-sized leeches (length up to 20 mm; Oosthuizen 1989); two pairs of eyespots on III (eyespots of the first pair are strongly reduced and usually joined with the second pair; eyespots of the second pair are larger, round or angulate, merging); body with 68 - 70 annuli, mid-body somites triannulate; dorsum with three or five longitudinal rows of prominent tubercles; mouth pore is shifted to the anterior part of the anterior sucker; salivary glands diffuse, extensively developed; proboscis slender; esophagus long, slender, slightly muscular; esophageal organ present; seven weakly branched pairs of crop caeca; gonopores separated by two annuli: male gonopore on furrow XI a 3 / XII a 1 and female gonopore on furrow XII a 2 / XII a 3; six pairs of testisacs; eggs carried in temporary, ventral brood chamber but not attached to the body; posterior sucker is small, circular, ventrally directed.	en	Bolotov, Ivan N., Eliseeva, Tatyana A., Marin, Ivan N., Palatov, Dmitry M., Nguyen, Trung Duc, Kropotin, Alexander V., Gofarov, Mikhail Y., Kondakov, Alexander V. (2025): Arthropod-associated leeches (Annelida: Hirudinida) of the World: Diversity, taxonomic reappraisal, ecological classification of host associations, and convergent evolution. Ecologica Montenegrina 89: 38-86, DOI: 10.37828/em.2025.89.3, URL: https://doi.org/10.37828/em.2025.89.3
C33FF42BCD05FF96C682DD28FCB6FD52.taxon	distribution	Distribution. Africa, South Asia (India and Sri Lanka), South-East Asia (Myanmar, Thailand, and Vietnam), East Asia (South Korea), and the Greater Sunda Islands (Java, Indonesia). The former representative of this genus from Europe was recently transferred to its own monotypic genus: Eurobdelloides moogi (Nesemann & Csányi, 1995) (Bolotov and Pešić 2025). The latter taxon is a relict phylogenetic lineage and does not relate to the Batracobdelloides clade but has some degree of convergent morphological similarity with it. List of species. The genus contains 12 accepted species: Batracobdelloides amnicolus (Moore, 1958) [Republic of South Africa, Namibia, Lesotho, and Botswana]; B. bangkhenensis Chiangkul et al., 2021 [Thailand]; B. conchophylus Bolotov et al., 2019 [Myanmar]; B. fulvus (Harding, 1924) comb. nov. [India]; B. gracilis (Blanchard, 1897) comb. nov. [Java, Indonesia]; B. hlaingbweensis Bolotov et al., 2019 [Myanmar]; B. indochinensis Bolotov et al., 2019 [Myanmar]; B. koreanus Bolotov et al., 2019 [South Korea]; B. reticulatus (Kaburaki, 1921) [India]; B. tricarinatus (Blanchard, 1897) [Tanzania, Kenya, Uganda, Democratic Republic of the Congo, Angola, Sudan, Ghana, Zambia, Egypt, and, probably, Israel]; B. undulatus (Harding, 1924) comb. nov. [Sri Lanka, and, probably, India]; B. yaukthwa Bolotov et al., 2019 [Myanmar] (Oosthuizen 1989; Bolotov et al. 2019; Chiangkul et al. 2021 b). Additionally, our samples contain three new mussel-associated Batracobdelloides species from South-East Asia (see Figure 7 and Table S 1) that will be described elsewhere.	en	Bolotov, Ivan N., Eliseeva, Tatyana A., Marin, Ivan N., Palatov, Dmitry M., Nguyen, Trung Duc, Kropotin, Alexander V., Gofarov, Mikhail Y., Kondakov, Alexander V. (2025): Arthropod-associated leeches (Annelida: Hirudinida) of the World: Diversity, taxonomic reappraisal, ecological classification of host associations, and convergent evolution. Ecologica Montenegrina 89: 38-86, DOI: 10.37828/em.2025.89.3, URL: https://doi.org/10.37828/em.2025.89.3
C33FF42BCD05FF96C682DD28FCB6FD52.taxon	biology_ecology	Hosts. Typically, freshwater molluscs act as shelter / dwelling place and / or secondary host and freshwater fishes serve as primary host (Bolotov et al. 2019; Chiangkul et al. 2021 b). However, available observations indicate that freshwater crabs may act as phoretic / dwelling host for two species (Table 3).	en	Bolotov, Ivan N., Eliseeva, Tatyana A., Marin, Ivan N., Palatov, Dmitry M., Nguyen, Trung Duc, Kropotin, Alexander V., Gofarov, Mikhail Y., Kondakov, Alexander V. (2025): Arthropod-associated leeches (Annelida: Hirudinida) of the World: Diversity, taxonomic reappraisal, ecological classification of host associations, and convergent evolution. Ecologica Montenegrina 89: 38-86, DOI: 10.37828/em.2025.89.3, URL: https://doi.org/10.37828/em.2025.89.3
C33FF42BCD05FF96C682DD28FCB6FD52.taxon	discussion	Comments. Here, we transfer three nominal species from other genera to Batracobdelloides based on morphological features and propose new combinations as follows: (1) Batracobdelloides fulvus (Harding, 1924) comb. nov. [= Placobdella fulva Harding, 1924; = Placobdelloides fulva (Harding, 1924); type locality: Purulia, 23.33 ° N, 86.36 ° E, West Bengal, India; phoretic / dwelling host: freshwater crab Maydelliathelphusa lugubris (Wood-Mason, 1871) (Gecarcinucidae); primary host: unknown (most likely fish)] (Harding 1924; Soós 1969; Sawyer 1986); (2) Batracobdelloides gracilis (Blanchard, 1897) comb. nov. [= Helobdella gracilis Blanchard, 1897; = Placobdella gracilis (Blanchard, 1897); = Batracobdella gracilis (Blanchard, 1897); type locality: Bogor, 6.60 ° S, 106.80 ° E, Java Island, Indonesia; host: phoretic / dwelling host: freshwater crab Parathelphusa sp. (Gecarcinucidae); primary host: unknown (most likely fish)] (Blanchard 1897; Soós 1969; Sawyer 1986); (3) Batracobdelloides undulatus (Harding, 1924) comb. nov. [= Placobdella undulata Harding, 1924; = Placobdelloides undulata (Harding, 1924); type locality: Colombo Lake [Beira Lake, 6.9294 ° N, 79.8542 ° E], Sri Lanka; host: fish Etroplus suratensis (Bloch, 1790) (Cichlidae)] (Harding 1924; Soós 1969; Sawyer 1986). It should be noted that fixed samples of Batracobdelloides often appear as bioculate leeches, because the anterior pair of eyespots is very small and is easily disappeared under the influence of a preservative fluid (Bolotov et al. 2019). For this reason, the nominal species, listed above, were placed in Placobdella, Helobdella and / or Placobdelloides.	en	Bolotov, Ivan N., Eliseeva, Tatyana A., Marin, Ivan N., Palatov, Dmitry M., Nguyen, Trung Duc, Kropotin, Alexander V., Gofarov, Mikhail Y., Kondakov, Alexander V. (2025): Arthropod-associated leeches (Annelida: Hirudinida) of the World: Diversity, taxonomic reappraisal, ecological classification of host associations, and convergent evolution. Ecologica Montenegrina 89: 38-86, DOI: 10.37828/em.2025.89.3, URL: https://doi.org/10.37828/em.2025.89.3
C33FF42BCD06FF96C682DD0AFE65F872.taxon	description	Figure S 5 https: // zoobank. org / urn: lsid: zoobank. org: act: D 085957 B- 0 D 0 A- 47 C 4 - 8 DCF-DE 6629 AA 83 DE	en	Bolotov, Ivan N., Eliseeva, Tatyana A., Marin, Ivan N., Palatov, Dmitry M., Nguyen, Trung Duc, Kropotin, Alexander V., Gofarov, Mikhail Y., Kondakov, Alexander V. (2025): Arthropod-associated leeches (Annelida: Hirudinida) of the World: Diversity, taxonomic reappraisal, ecological classification of host associations, and convergent evolution. Ecologica Montenegrina 89: 38-86, DOI: 10.37828/em.2025.89.3, URL: https://doi.org/10.37828/em.2025.89.3
C33FF42BCD06FF96C682DD0AFE65F872.taxon	type_taxon	Type species. Placobdella ornata Oka, 1929 [= Placobdella okai Soós, 1969; replacement name that is rejected by us based on Art. 59.4 of the Code (ICZN 1999)].	en	Bolotov, Ivan N., Eliseeva, Tatyana A., Marin, Ivan N., Palatov, Dmitry M., Nguyen, Trung Duc, Kropotin, Alexander V., Gofarov, Mikhail Y., Kondakov, Alexander V. (2025): Arthropod-associated leeches (Annelida: Hirudinida) of the World: Diversity, taxonomic reappraisal, ecological classification of host associations, and convergent evolution. Ecologica Montenegrina 89: 38-86, DOI: 10.37828/em.2025.89.3, URL: https://doi.org/10.37828/em.2025.89.3
C33FF42BCD06FF96C682DD0AFE65F872.taxon	diagnosis	Differential diagnosis. Small leeches (length up to 12 mm); one pair of cup-shaped (sometimes triangular or round) eyespots on II (in some cases, eyespots are invisible but can be detected histologically as aggregations of visual cells); characteristic dorsal pigmentation patterns with deep chocolate brown ground color, yellow or white longitudinal medial band and lateral yellow or white band or large spots, two or four series of yellow or white spots at a 2 (outer paramarginal or outer paramarginal and outer paramedian position); posterior sucker with yellow or white edge and a series of light spots along the margin (Figure S 5); body with 66 - 67 annuli, mid-body somites triannulate; dorsum is densely covered with small, closely set papillae; mouth pore is subterminal; one pair of compact salivary glands; seven pairs of crop caeca; six pairs of testisacs; gonopores separated by two annuli: male gonopore on furrow XI a 3 / XII a 1 and female gonopore on furrow XII a 2 / XII a 3 (Palaemobdella horai) or male gonopore on XI a 3 and female gonopore on XII a 2 (Palaemobdella ornata); posterior sucker is small, circular, ventrally directed. Phylogenetic data are not available.	en	Bolotov, Ivan N., Eliseeva, Tatyana A., Marin, Ivan N., Palatov, Dmitry M., Nguyen, Trung Duc, Kropotin, Alexander V., Gofarov, Mikhail Y., Kondakov, Alexander V. (2025): Arthropod-associated leeches (Annelida: Hirudinida) of the World: Diversity, taxonomic reappraisal, ecological classification of host associations, and convergent evolution. Ecologica Montenegrina 89: 38-86, DOI: 10.37828/em.2025.89.3, URL: https://doi.org/10.37828/em.2025.89.3
C33FF42BCD06FF96C682DD0AFE65F872.taxon	etymology	Etymology. The name of this genus is combined from two parts: ‘ Palaemo ’ (reference to its crustacean hosts, the family Palaemonidae) and ‘ bdella ’ (leech in Greek).	en	Bolotov, Ivan N., Eliseeva, Tatyana A., Marin, Ivan N., Palatov, Dmitry M., Nguyen, Trung Duc, Kropotin, Alexander V., Gofarov, Mikhail Y., Kondakov, Alexander V. (2025): Arthropod-associated leeches (Annelida: Hirudinida) of the World: Diversity, taxonomic reappraisal, ecological classification of host associations, and convergent evolution. Ecologica Montenegrina 89: 38-86, DOI: 10.37828/em.2025.89.3, URL: https://doi.org/10.37828/em.2025.89.3
C33FF42BCD06FF96C682DD0AFE65F872.taxon	distribution	Distribution. The new genus seems to have a disjunctive range (Baugh 1960 a; Lai and Chen 2010). In particular, there are records from India (known only from a small lake in West Bengal) and Taiwan (known from a few localities in the middle and southern part of the island) (Figure 12). However, we assume that some additional species of this genus may occur within a continuous gap between India and Taiwan. These inconspicuous shrimp-associated leeches might have been overlooked by researchers, as it was the case for a diverse assemblage of mussel-associated leeches (Bolotov et al. 2019). List of species. Palaemobdella ornata (Oka, 1929) gen. & comb. nov. [Taiwan] and Pe. horai (Baugh, 1960) comb. nov. [India] (Table 3).	en	Bolotov, Ivan N., Eliseeva, Tatyana A., Marin, Ivan N., Palatov, Dmitry M., Nguyen, Trung Duc, Kropotin, Alexander V., Gofarov, Mikhail Y., Kondakov, Alexander V. (2025): Arthropod-associated leeches (Annelida: Hirudinida) of the World: Diversity, taxonomic reappraisal, ecological classification of host associations, and convergent evolution. Ecologica Montenegrina 89: 38-86, DOI: 10.37828/em.2025.89.3, URL: https://doi.org/10.37828/em.2025.89.3
C33FF42BCD06FF96C682DD0AFE65F872.taxon	biology_ecology	Hosts. Freshwater shrimps (Palaemonidae; phoretic / dwelling host) and fishes (Cyprinidae and Synbranchidae; primary host) (Baugh 1960 a; Lai and Chen 2010).	en	Bolotov, Ivan N., Eliseeva, Tatyana A., Marin, Ivan N., Palatov, Dmitry M., Nguyen, Trung Duc, Kropotin, Alexander V., Gofarov, Mikhail Y., Kondakov, Alexander V. (2025): Arthropod-associated leeches (Annelida: Hirudinida) of the World: Diversity, taxonomic reappraisal, ecological classification of host associations, and convergent evolution. Ecologica Montenegrina 89: 38-86, DOI: 10.37828/em.2025.89.3, URL: https://doi.org/10.37828/em.2025.89.3
C33FF42BCD06FF96C682DD0AFE65F872.taxon	discussion	Comments. Previously, the two shrimp-associated species of the new genus were placed in Placobdelloides (see Sawyer 1986) but they differ from its members by the lack of esophageal glands, the smaller number of annuli (66 - 67 vs. 70 - 71), the position of eyespots on II, and a very specific dorsal pigmentation patterns.	en	Bolotov, Ivan N., Eliseeva, Tatyana A., Marin, Ivan N., Palatov, Dmitry M., Nguyen, Trung Duc, Kropotin, Alexander V., Gofarov, Mikhail Y., Kondakov, Alexander V. (2025): Arthropod-associated leeches (Annelida: Hirudinida) of the World: Diversity, taxonomic reappraisal, ecological classification of host associations, and convergent evolution. Ecologica Montenegrina 89: 38-86, DOI: 10.37828/em.2025.89.3, URL: https://doi.org/10.37828/em.2025.89.3
C33FF42BCD07FF91C682DE8DFDBEFECF.taxon	type_taxon	Type species. Clepsine multistriata Johansson, 1909 (by original designations)	en	Bolotov, Ivan N., Eliseeva, Tatyana A., Marin, Ivan N., Palatov, Dmitry M., Nguyen, Trung Duc, Kropotin, Alexander V., Gofarov, Mikhail Y., Kondakov, Alexander V. (2025): Arthropod-associated leeches (Annelida: Hirudinida) of the World: Diversity, taxonomic reappraisal, ecological classification of host associations, and convergent evolution. Ecologica Montenegrina 89: 38-86, DOI: 10.37828/em.2025.89.3, URL: https://doi.org/10.37828/em.2025.89.3
C33FF42BCD07FF91C682DE8DFDBEFECF.taxon	diagnosis	Differential diagnosis. Medium-sized leeches (length up to 40 mm; Oosthuizen 1979); one pair of eyespots on III; body with 70 annuli, mid-body somites triannulate; dorsum with six rows of conical papillae at a 2 and with multiple small, irregularly arranged papillae on each annulus; mouth pore is terminal; one or two pairs of compact salivary glands; esophageal glands present; seven pairs of crop caeca (2 nd to 6 th pairs of crop caeca each with three lobes); six pairs of testisacs; the gonopores separated by two annuli: male gonopore on XI a 3 / XII a 1, female gonopore on XII a 2 / XII a 3; posterior sucker of large or moderate size, circular, ventrally directed. Phylogenetically, this genus is sister to the Marsupiobdella lineage (Figure 7).	en	Bolotov, Ivan N., Eliseeva, Tatyana A., Marin, Ivan N., Palatov, Dmitry M., Nguyen, Trung Duc, Kropotin, Alexander V., Gofarov, Mikhail Y., Kondakov, Alexander V. (2025): Arthropod-associated leeches (Annelida: Hirudinida) of the World: Diversity, taxonomic reappraisal, ecological classification of host associations, and convergent evolution. Ecologica Montenegrina 89: 38-86, DOI: 10.37828/em.2025.89.3, URL: https://doi.org/10.37828/em.2025.89.3
C33FF42BCD07FF91C682DE8DFDBEFECF.taxon	distribution	Distribution. Africa, Madagascar, Yemen, Malaysia, and Singapore (Oosthuizen 1979; Bolotov et al. 2022 b; Bolotov et al. 2023 a). List of species. Apparently, Placobdelloides s. str. contains two reptilian-associated African species, that is, Pl. multistriatus (Johansson, 1909) [the type species of the genus; continental Africa, Madagascar, and Yemen; host: turtles, terrapins, and crocodiles] and Pl. fimbriatus (Johansson, 1909) [Uganda, Kenya, Nigeria; host: crocodiles] (Moore 1939; Cott 1961; Oosthuizen 1979; Oosthuizen 1991; Bolotov et al. 2022 b; Bolotov et al. 2023 a). Morphological features of Pl. stellapapillosus Govedich, Bain & Davies, 2002 [Singapore and Malaysia; host: turtles, crocodiles, and gavials] partly agree with the diagnosis of this genus (one pair of eyespots, one pair of compact salivary glands, six pairs of testisacs, two annuli between the gonopores, seven pairs of lobed crop caeca) (Sawyer 1986; Govedich et al. 2002; Neely et al. 2017). Conversely, two specific traits, that is, the position of eyespots on I or II and the presence of unique star-shaped papillae on its dorsum, indicate that the generic placement of this species needs future research based on the DNA sequence data.	en	Bolotov, Ivan N., Eliseeva, Tatyana A., Marin, Ivan N., Palatov, Dmitry M., Nguyen, Trung Duc, Kropotin, Alexander V., Gofarov, Mikhail Y., Kondakov, Alexander V. (2025): Arthropod-associated leeches (Annelida: Hirudinida) of the World: Diversity, taxonomic reappraisal, ecological classification of host associations, and convergent evolution. Ecologica Montenegrina 89: 38-86, DOI: 10.37828/em.2025.89.3, URL: https://doi.org/10.37828/em.2025.89.3
C33FF42BCD07FF91C682DE8DFDBEFECF.taxon	biology_ecology	Hosts. Crocodiles, gavials, turtles, and terrapins serve as primary hosts (reptilian-associated leeches). Water bugs (Hemiptera) were recorded as phoretic host for the two African species (Table 3).	en	Bolotov, Ivan N., Eliseeva, Tatyana A., Marin, Ivan N., Palatov, Dmitry M., Nguyen, Trung Duc, Kropotin, Alexander V., Gofarov, Mikhail Y., Kondakov, Alexander V. (2025): Arthropod-associated leeches (Annelida: Hirudinida) of the World: Diversity, taxonomic reappraisal, ecological classification of host associations, and convergent evolution. Ecologica Montenegrina 89: 38-86, DOI: 10.37828/em.2025.89.3, URL: https://doi.org/10.37828/em.2025.89.3
C33FF42BCD07FF91C682DE8DFDBEFECF.taxon	discussion	Comments. This genus in its original understanding (Sawyer 1986) was a paraphyletic group (Bolotov et al. 2022 b). Here, four Placobdelloides species transferred to Palaemobdella gen. nov. (two species) and Batracobdelloides (two species) (see the corresponding accounts above for detail). An African member of the genus, Placobdelloides jaegerskioeldi (Johansson, 1909), represents a distant phylogenetic lineage and was recently placed in the monotypic genus Hippobdelloides Bolotov & Pešić, 2025 (Bolotov and Pešić 2025). Turtle-associated Placobdelloides leeches from tropical Asia were also found to be a separate clade that was described as the genus Orientobdelloides Bolotov, Eliseeva & Kondakov, 2022 (Bolotov et al. 2022 b). Three former members of Placobdelloides were placed in the genus Orientobdelloides as follows: Or. siamensis (Oka, 1917) [the type species of the genus], Or. sirikanchanae (Trivalairat, Chiangkul & Purivirojkul, 2019), and Or. tridens (Chiangkul, Trivalairat, Kunya & Purivirojkul, 2021). Based on morphological features, six additional nominal species should be considered representatives of this group: (1) Orientobdelloides emydae (Harding, 1920) comb. nov. [= Placobdella emydae Harding, 1920; = Placobdelloides emydae (Harding, 1920); composite type locality: ‘ Station No. 52, 4 - 9 mi. E. 1 / 2 N. of Patsahanipur, Lake Chilka’; ‘ outskirts of Calcutta’; ‘ Gatiagurh, Dist. Hughly, Bengal’; ‘ R. Mahanaddi, Sambalpur, Orissa’; ‘ near Purulia, Chota Nagpur Div., Bihar’; ‘ Nagpur, C. P. ’, India; range: India; host: turtle Lissemys punctata (Lacépède, 1788) (Trionychidae)] (Harding 1920; Harding and Moore 1927; Sawyer 1986); (2) Orientobdelloides indicus (Baugh, 1960) comb. nov. [= Placobdella indica Baugh, 1960; = Placobdelloides indica (Baugh, 1960); type locality: ‘ a rocky pool ‘ Sitkundi’ in Kalipahar about 7 miles S. W. of Monghyr Dist. (Bihar) ’, approx. 25.3105 ° N, 86.5052 ° E, India; range: India; host: unknown (likely freshwater turtles)] (Baugh 1960 b; Sawyer 1986); (3) Orientobdelloides inleanus (Oka, 1922) comb. nov. [= Glossiphonia inleana Oka, 1922; = Placobdella inleana (Oka, 1922); type locality: ‘ Fort Stedman, Inle Lake’, approx. 20.5773 ° N, 96.9436 ° E, Myanmar; range: Myanmar; host: turtle Cyclemys oldhami shanensis Annandale, 1918 (Geoemydidae)] (Oka 1922; Harding and Moore 1927); (4) Orientobdelloides guangdongensis (Tan & Liu, 2001) comb. nov. [= Hemiclepsis guangdongensis Tan & Liu, 2001; type locality: Guangzhou City, approx. 23.02 ° N, 113.03 ° E, Guangdong Province, China; range: Pearl River basin, South-East China; host: turtle Cuora amboinensis (Daudin, 1801) (Geoemydidae)] (Tan and Liu 2001); (5) Orientobdelloides bancrofti (Best, 1931) comb. nov. [= Helobdella bancrofti Best, 1931; = Placobdella bancrofti (Best, 1931); = Placobdelloides bancrofti (Best, 1931); type locality: Burnett River, Queensland, Australia; range: Australia; host: turtles Emydura macquarii krefftii (Gray, 1871) and Myuchelys latisternum (Gray, 1867) (Chelidae)] (Best 1931; Sawyer 1986; Govedich 2001; McKenna et al. 2005); (6) Orientobdelloides octostriatus (Grube, 1867) comb. nov. [= Clepsine octostriata Grube, 1867; = Placobdelloides octostriata (Grube, 1867); type locality: Rockhampton, approx. 23.3739 ° S, 150.5128 ° E, Queensland, Australia; range: Australia; host: turtles Emydura australis (Gray, 1841) and Chelodina burrungandjii Thomson, Kennett & Georges, 2000 (Chelidae)] (Grube 1867; Grube 1871; Govedich 2001; Tucker et al. 2005). Two nominal species, that is, Orientobdelloides tridens and Or. indicus, are characterized as having trident-shaped (trilobate) crop caeca (Figure S 6). This pattern was considered a unique diagnostic trait of the first species (Chiangkul et al. 2021 a; Kambayashi et al. 2024). However, Orientobdelloides tridens differs from Or. indicus by having one pair of compact salivary glands (vs. two pairs) (Figure S 6). It should be noted that Orientobdelloides tridens was recently discovered from Java, Indonesia (Kambayashi et al. 2024). This record reveals that the range of this turtle-associated species is broader than it was initially expected (Chiangkul et al. 2021 a), although populations of this leech on Java and in Thailand are rather distant phylogenetically (the uncorrected COI p-distance = 5.2 %) (Kambayashi et al. 2024). The data, outlined above, indicate that there may be a species complex of leeches with trident-shaped crop caeca, containing Or. tridens, Or. indicus, and some additional species. Next, Placobdelloides okadai (Oka, 1925) [= Hemiclepsis okadai Oka, 1925; = Placobdella okadai (Oka, 1925)] was described based on a composite type series that contains specimens collected from the Ryukyu Archipelago of Japan [Amami Ōshima Island and Shuri on Okinawa Island; host: frogs Limnonectes namiyei (Stejneger, 1901) (Dicroglossidae) and Babina holsti (Boulenger, 1892) (Ranidae)] and from North China (Beijing; host: unspecified turtle) (Oka 1925; Soós 1969; Sawyer 1986). The description and illustrations of the species are mostly based on the Japanese specimens (Oka 1925) and, hence, the type locality could be restricted to the two islands of the Ryukyu Archipelago. According to the protologue, this nominal species is characterized by the following combination of characters: small leeches (length up to 15 mm); live animal has uniform dark olive ground color, without bands and spots; one pair of eyespots on II (very close to each other); dorsum smooth; body with 66 annuli: somites I-IV uniannulate, V-VI biannulate, VII-VIII ' transitional from biannulate to triannulate' [calculated as biannulate by Oka], IX-XXV triannulate, XXVI biannulate, XXVII uniannulate; the mouth pore is terminal; seven pairs of branched crop caeca; six pairs of testisacs; the gonopores separated by two annuli: male gonopore on XI a 3 / XII a 1, female gonopore on XII a 2 / XII a 3; very large posterior sucker (diameter as great as the body width) (Oka 1925). The salivary glands are not described. Oka (1925) also noted that this species externally resembles the biannulate species Oligobdella orientalis (Oka, 1925) [synonym of Torix tagoi (Oka, 1925); Kambayashi and Nakano 2023] and Oligobdella biannulata (Moore, 1900) [now Placobdella biannulata; Siddall et al. 2005]. Indeed, most features of Placobdelloides okadai agree with the diagnosis of the genus Torix Blanchard, 1893, except for triannulate mid-body somites (vs. biannulate) (Kambayashi and Nakano 2023). In our opinion, Placobdelloides okadai could be considered a member of the latter genus, morphologically representing a transitional form from triannulate to biannulate condition. It is known that triannulate and biannulate species may occur within one genus (e. g., Placobdella biannulata) (Siddall et al. 2005). As a conclusion, we propose a new combination as follows: Torix okadai (Oka, 1925) comb. nov. It can be considered endemic to the Ryukyu Islands and may represent a sister lineage to Torix tagoi, although this preliminary hypothesis needs to be confirmed in the future by means of a DNA-based approach. The part of the type series of this nominal species collected from the mouth of a turtle in Beijing may belong to a species of the genus Mooreotorix Lukin, 1976. In turn, records of ‘ Placobdelloides okadai ’ from Honshu (Yamauchi et al. 2008) most likely belong to Torix tagoi (see Kambayashi and Nakano 2023). A specimen of ‘ Placobdella okadai ’ from Nanking, China described by Moore (1930) may belong to an additional species of Torix. Finally, morphological features of Placobdelloides bdellae (Ingram, 1957) and Placobdelloides maorica (Benham, 1907) from Tasmania and New Zealand, respectively (Benham 1907; Ingram 1957; Mason 1974; Sawyer 1986; Govedich 2001) do not fully consistent with the differential diagnosis of Placobdelloides s. str. (see above). In particular, these species can be distinguished from representatives of the latter genus by having a greatly enlarged and anteriorly directed first pair of crop caeca (vs. small, laterally or antero-laterally directed) (Figure S 7). Therefore, we propose a new genus to incorporate these two species (see below).	en	Bolotov, Ivan N., Eliseeva, Tatyana A., Marin, Ivan N., Palatov, Dmitry M., Nguyen, Trung Duc, Kropotin, Alexander V., Gofarov, Mikhail Y., Kondakov, Alexander V. (2025): Arthropod-associated leeches (Annelida: Hirudinida) of the World: Diversity, taxonomic reappraisal, ecological classification of host associations, and convergent evolution. Ecologica Montenegrina 89: 38-86, DOI: 10.37828/em.2025.89.3, URL: https://doi.org/10.37828/em.2025.89.3
C33FF42BCD01FF91C682DFE1FEC5FACA.taxon	description	Figure S 7 https: // zoobank. org / urn: lsid: zoobank. org: act: 439 BA 4 D 8 - D 762 - 4 D 71 - B 805 - CC 28 FF 06865 C	en	Bolotov, Ivan N., Eliseeva, Tatyana A., Marin, Ivan N., Palatov, Dmitry M., Nguyen, Trung Duc, Kropotin, Alexander V., Gofarov, Mikhail Y., Kondakov, Alexander V. (2025): Arthropod-associated leeches (Annelida: Hirudinida) of the World: Diversity, taxonomic reappraisal, ecological classification of host associations, and convergent evolution. Ecologica Montenegrina 89: 38-86, DOI: 10.37828/em.2025.89.3, URL: https://doi.org/10.37828/em.2025.89.3
C33FF42BCD01FF91C682DFE1FEC5FACA.taxon	type_taxon	Type species. Placobdella maorica Benham, 1907.	en	Bolotov, Ivan N., Eliseeva, Tatyana A., Marin, Ivan N., Palatov, Dmitry M., Nguyen, Trung Duc, Kropotin, Alexander V., Gofarov, Mikhail Y., Kondakov, Alexander V. (2025): Arthropod-associated leeches (Annelida: Hirudinida) of the World: Diversity, taxonomic reappraisal, ecological classification of host associations, and convergent evolution. Ecologica Montenegrina 89: 38-86, DOI: 10.37828/em.2025.89.3, URL: https://doi.org/10.37828/em.2025.89.3
C33FF42BCD01FF91C682DFE1FEC5FACA.taxon	diagnosis	Differential diagnosis. Small leeches (length up to 16 mm; Mason 1974); one pair of eyespots on III; body with 69 - 70 annuli, mid-body somites triannulate; mouth pore is subterminal; one pair of compact salivary glands; small esophageal glands present; seven pairs of branched crop caeca; the first pair of crop caeca are anteriorly directed and are approximately 1.5 - 2 times longer than those of the 2 nd – 6 th pairs; six pairs of testisacs; gonopores separated by two annuli: male gonopore on furrow XI a 3 / XII a 1 and female gonopore on furrow XII a 2 / XII a 3; posterior sucker is small, circular, ventrally directed; phylogenetic data are not available.	en	Bolotov, Ivan N., Eliseeva, Tatyana A., Marin, Ivan N., Palatov, Dmitry M., Nguyen, Trung Duc, Kropotin, Alexander V., Gofarov, Mikhail Y., Kondakov, Alexander V. (2025): Arthropod-associated leeches (Annelida: Hirudinida) of the World: Diversity, taxonomic reappraisal, ecological classification of host associations, and convergent evolution. Ecologica Montenegrina 89: 38-86, DOI: 10.37828/em.2025.89.3, URL: https://doi.org/10.37828/em.2025.89.3
C33FF42BCD01FF91C682DFE1FEC5FACA.taxon	etymology	Etymology. the name of this genus is combined from two parts, that is, ‘ Aotearoa ’ (Maori name for New Zealand) and ‘ bdella ’ (leech in Greek).	en	Bolotov, Ivan N., Eliseeva, Tatyana A., Marin, Ivan N., Palatov, Dmitry M., Nguyen, Trung Duc, Kropotin, Alexander V., Gofarov, Mikhail Y., Kondakov, Alexander V. (2025): Arthropod-associated leeches (Annelida: Hirudinida) of the World: Diversity, taxonomic reappraisal, ecological classification of host associations, and convergent evolution. Ecologica Montenegrina 89: 38-86, DOI: 10.37828/em.2025.89.3, URL: https://doi.org/10.37828/em.2025.89.3
C33FF42BCD01FF91C682DFE1FEC5FACA.taxon	distribution	Distribution. New Zealand and Tasmania. List of species. Two new combinations are proposed as follows: (1) Aotearoabdella maorica (Benham, 1907) gen. & comb. nov. [= Placobdella maorica Benham, 1907; = Placobdelloides maorica (Benham, 1907); type locality: Ruapuke Island, 46.76 ° S, 168.52 ° E, New Zealand; range: New Zealand; host: Pacific black duck Anas superciliosa Gmelin, 1789 (Anatidae) and man] (Benham 1907; Mason 1974; Sawyer 1986; Govedich 2001); (2) Aotearoabdella bdellae (Ingram, 1957) comb. nov. [= Placobdella bdellae Ingram, 1957; = Placobdelloides bdellae (Ingram, 1957); type locality: Salmon Ponds, 42.7557 ° S, 146.9682 ° E, Plenty River, Tasmania (based on the label of syntypes from D. M. Ingram leech collection: TMAG K 0737; K 0738; K 0739; K 0740; K 0741; and K 0784); range: Tasmania; host: pouched lamprey Geotria australis Gray, 1851 (Geotriidae)] (Ingram 1957; Mason 1974; Sawyer 1986).	en	Bolotov, Ivan N., Eliseeva, Tatyana A., Marin, Ivan N., Palatov, Dmitry M., Nguyen, Trung Duc, Kropotin, Alexander V., Gofarov, Mikhail Y., Kondakov, Alexander V. (2025): Arthropod-associated leeches (Annelida: Hirudinida) of the World: Diversity, taxonomic reappraisal, ecological classification of host associations, and convergent evolution. Ecologica Montenegrina 89: 38-86, DOI: 10.37828/em.2025.89.3, URL: https://doi.org/10.37828/em.2025.89.3
C33FF42BCD01FF91C682DFE1FEC5FACA.taxon	discussion	Discussion	en	Bolotov, Ivan N., Eliseeva, Tatyana A., Marin, Ivan N., Palatov, Dmitry M., Nguyen, Trung Duc, Kropotin, Alexander V., Gofarov, Mikhail Y., Kondakov, Alexander V. (2025): Arthropod-associated leeches (Annelida: Hirudinida) of the World: Diversity, taxonomic reappraisal, ecological classification of host associations, and convergent evolution. Ecologica Montenegrina 89: 38-86, DOI: 10.37828/em.2025.89.3, URL: https://doi.org/10.37828/em.2025.89.3
