Table 1 Mussel-associated leeches of the World (obligate and facultative inhabitants of the mantle cavity of freshwater mussels) with supplement of an overview of free-living species in the genera Batracobdelloides Oosthuizen, 1986 and Hemiclepsis Vejdovsky, 1884 (complete checklist of these genera is presented as Supplementary Note 1).

P. montifera Moore, 1906

Facultative inhabitant of the mantle cavity of freshwater mussels

Long Point, Canada⁷⁶

Widespread throughout USA and Canada¹³

Secondary host and shelter (facultative): freshwater mussels Amblema, Cyclonaias, Fusconaia, Glebula, Lampsilis, Leptodea, Obliquaria, Potamilus, Pyganodon, Utterbackiana (Unionidae: Ambleminae)^1,10,11,12; primary host: freshwater fishes Acipenser, Scaphirhynchus (Acipenseridae), Perca (Percidae), Lepomis, Micropterus (Centrarchidae), Lepisosteus (Lepisosteidae), Ameiurus (Ictaluridae), Moxostoma (Catostomidae), Cyprinus (Cyprinidae), and common musk turtle Stenotherus odoratus (Kinosternidae)^10,13

P. parasitica (Say, 1824)

Facultative inhabitant of the mantle cavity of freshwater mussels¹

The lakes of the north-western region [of North America]⁷⁷

North-central and eastern USA and southern Canada^13,78

Secondary host and shelter (facultative): unspecified freshwater mussels (Unionidae: Ambleminae)¹; primary host: at least 10 freshwater turtle species^72,78, occasional records from the tadpoles of Lithobates pipiens (Ranidae) and a freshwater fish⁷²

B. conchophylus sp. nov.

Possible obligate inhabitant of the mantle cavity of freshwater mussels

Myanmar, Lower Sittaung Basin, ox-bow lake near Taung Gyi village, 17.8807°N, 96.8313°E

Myanmar: Sittaung and Haungthayaw river basins

Secondary host and shelter: freshwater mussels Radiatula and Lamellidens (Unionidae: Parreysiinae); primary host: freshwater fishes Wallago (Siluridae)

B. hlaingbweensis sp. nov.

Possible obligate inhabitant of the mantle cavity of freshwater mussels

Myanmar, Hlaingbwe Basin, small stream, 17.0292°N, 97.8099°E

Myanmar: Hlaingbwe River basin

Secondary host and shelter: freshwater mussels Pseudodon (Unionidae: Gonideinae); primary host: freshwater fishes Hemibagrus (Bagridae)

B. indochinensis sp. nov.

Possible obligate inhabitant of the mantle cavity of freshwater mussels

Myanmar, Salween Basin, fish pond near Demoso, 19.7289°N, 97.1167°E

Myanmar: Bago, Sittaung, Ayeyarwady, and Salween river basins

Secondary host and shelter: freshwater mussels Lamellidens and Trapezidens (Unionidae: Parreysiinae); primary host: freshwater fishes Clarias (Clariidae) and Oreochromis (Cichlidae)

B. yaukthwa sp. nov.

Possible obligate inhabitant of the mantle cavity of freshwater mussels

Myanmar, Middle Sittaung Basin, Chain Stream, 17.9769°N, 96.7650°E

Myanmar: Ayeyarwady and Sittaung river basins

Secondary host and shelter: freshwater mussels Trapezidens and Indochinella (Unionidae: Parreysiinae); primary host: freshwater fishes Macrognathus (Mastacembelidae)

B. koreanus sp. nov.

Possible obligate inhabitant of the mantle cavity of freshwater mussels

South Korea, Seomjin River, 35.7010°N, 127.2845°E

South Korea: Seomjin and Mangyeong river basins

Secondary host and shelter: freshwater mussels Nodularia (Unionidae: Unioninae); primary host: freshwater fishes Channa (Channidae)

*B. reticulatus (Kaburaki, 1921)

Possible obligate inhabitant of the mantle cavity of freshwater mussels^23,24,25

Jullundur [Jalandhar, Punjab, India]²³

India and Nepal^23,25,28,79

Secondary host and shelter: freshwater mussels Lamellidens (Unionidae: Parreysiinae)^23,25; primary host: probably freshwater fishes

B. tricarinatus (Blanchard, 1897)

Facultative inhabitant of the mantle cavity of freshwater mussels

Tanzania, Mbani (Ugogo), Bubu-Bach²⁶

Nile Basin and surrounding endorheic freshwater systems in Africa²⁶, records from Israel²⁶ are questionable

Secondary host and shelter (facultative): freshwater mussels Coelatura (Unionidae: Parreysiinae), Aspatharia, Chambardia, and Mutela (Iridinidae); primary host: freshwater fishes Synodontis (Mochokidae)

B. amnicolus (Moore, 1958) stat. rev.

Free-living species

South Africa, Zululand, Hluhluwe, Engamani River²⁶

South Africa^26,80

Freshwater fishes Clarias (Clariidae), Labeobarbus, Carassius (Cyprinidae), Oreochromis (Cichlidae), and unspecified amphibians^26,80

*B. moogi Nesemann & Csänyi, 1995

Free-living species

Hungary, Kisbalaton near the Zala River²⁸

Europe: Austria, Hungary, Italy, Lithuania, Montenegro, Poland, and Slovakia^28,70,81

Pulmonate freshwater snails, chiefly Planorbarius (Planorbidae)⁷⁰

H. kasmiana Oka, 1910 comb. rev.

Possible obligate inhabitant of the mantle cavity of freshwater mussels

Hondo (Kasumiga-Ura, Owari, Bizen) [Japan, Honshu: Lake Kasumigaura, Owari Province, and Bizen city]¹⁵

Widespread through Russian Far East, Korea, Japan, and China²¹

Secondary host and shelter: freshwater mussels Aculamprotula, Buldowskia, Cristaria, Inversunio, Middendorfinaia, Nodularia, Sinadonta (Unionidae: Unioninae), Lamprotula, Pronodularia, Obovalis (Unionidae: Gonideinae), Margaritifera dahurica (Margaritiferidae)^16,21,82; primary host: freshwater fishes Perccottus (Odontobutidae) and Silurus (Siluridae)

H. khankiana sp. nov.

Possible obligate inhabitant of the mantle cavity of freshwater mussels

Russia, Primorye Region, Khanka Lake Basin, Melgunovka River, 44.5804°N, 132.0803°E

Russian Far East: Khanka Lake, Amur Basin

Secondary host and shelter: freshwater mussels Nodularia (Unionidae: Unioninae); primary host: freshwater fishes Rhodeus (Cyprinidae)

H. myanmariana sp. nov.

Possible obligate inhabitant of the mantle cavity of freshwater mussels

Myanmar, Salween Basin, Nadi Lake, 20.6858°N, 96.9316°E

Myanmar: Ayeyarwady, Sittaung, Bilin, and Salween river basins

Secondary host and shelter: freshwater mussels Lamellidens and Indonaia (Unionidae: Parreysiinae); primary host: freshwater fishes Labeo (Cyprinidae)

H. schrencki sp. nov.

Free-living species

Russia, Primorye Region, Partizanskaya River, 43.0585°N, 133.1540°E

Russian Far East: Partizanskaya and Ussuri river basins

Freshwater fishes Barbatula and Phoxinus (Nemacheilidae)

H. tumniniana sp. nov.

Free-living species

Russia, Khabarovsk Region, Tumnin River, 50.0001°N, 139.9175°E

Russian Far East: Tumnin Basin

Freshwater fishes Pungitius (Gasterosteidae)

H. marginata (O. F. Müller, 1774)

Free-living species

Unknown, but most likely somewhere in Europe

Widespread through Europe and Siberia from the British Isles⁸³ up to the Yenisei Basin and Lake Baikal⁸⁴. Records from East and Southeast Asia^{16,19,25,29,85} refer to other taxa

Chiefly freshwater fishes and amphibian larvae, but also molluscs^29,85

*H. japonica (Oka, 1932)

Free-living species

Japan, Inokasira Pond near Tokyo, Honshu, and one specimen from Sapporo, Hokkaido⁸⁶

Honshu and Hokkaido Islands, Japan⁸⁶

Unknown²⁹

*H. erhaiensis Yang, 1981

Free-living species

China, Yunnan, Erhai Lake^19,87

China: Erhai, Dianchi and Chenghai lakes in Yunnan^19,87

Freshwater fishes^19,87

*H. guangdongensis Tan & Liu, 2001

Free-living species

China, Guangdong Province, Guangzhou (23.02°N, 113.03°E)⁸⁸

China: Lower Pearl River basin⁸⁸

Amboina box turtle Cuora amboinensis (Geoemydidae)⁸⁸

*H. hubeiensis Yang, 1981

Free-living species

China, Hubei, Huangzhou District, Sanshan Lake^19,87

China: Sanshan and Ya’er lakes in Yangtze Basin, Hubei^19,87

Freshwater fishes^19,87

*H. asiatica Moore, 1924 stat. rev.

Free-living species^25,89

India, Kashmir, Srinagar⁸⁹

India and probably Nepal^25,89

Freshwater fishes^25,90

*H. bhatiai Baugh, 1960

Free-living species^25,91,92

India, Bihar, rocky pool ‘Sitkundi’ in Kalipahar, ca. 7 miles SW of Monghyr District⁹¹

India: Bihar and Jammu and Kashmir^25,91,92

Unknown^25,29,91

*H. charwardamensis Mandal, 2013 [=H. chharwardamensis Mandal, 2013 syn. nov.; =H. ischharwardamensis Mandal, 2013 syn. nov. (our first reviser action on the precedence of simultaneous synonyms)]

Free-living species⁹³

India, Jharkhand, Bokaro, Charwardam [=Garga Dam?]⁹³

India: known only from the type locality⁹³

Unknown, although its association with freshwater molluscs and fishes was speculated by the author of this species⁹³ (Supplementary Note 1)

*H. viridis Chelladurai, 1934

Free-living species^25,92,94

India, Trivandrum [Kerala] and Ootacamund [Udagamandalam, Tamil Nadu]⁹⁴

India: Kerala and Tamil Nadu states^25,92

Frogs^29,94

H. sp.1

Unknown

n/a

South Korea: known from a single specimen

Unknown