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Limnesia (Limnesia) acuminata Walter, 1925 Type material: Holotype one male catalogue number NMB-ACWA 2713 deposited at NHMB (Pers. comm, U. Wüest) Type locality: Algeria: Jijel Province, Oued Nil (Walter 1925). Geographical distribution: European (France, Iberian Peninsula and Italy) and North African Mediterranean area (Gerecke et al. 2016). Distribution in Portugal: Centre: Beira Alta (in Santa Comba Dão, and Côa River, near 10 km to Vilar Formoso); South:Alentejo (in Ribeira de Odivelas, Ribeira do Roxo, and Guadiana River-between Serpa and Beja municipalities), Estremadura (in Colares-Sintra municipality) (Lundblad 1956; Valdecasas 1988). Ecological notes: Freshwater, at standing and slow-flowing freshwater ecosystems (Gerecke et al. 2016), shaded and clear tributaries, on a sandy bottom; present in plants, such as grasses Azolla spp., Batrachium spp., Carex spp., Juncus spp., Myriophyllum spp., Nymphea spp., Scirpus spp. (Lundblad 1956)., Published as part of Cantallo, Harold, Gomes, Nuno, Antunes, Carlos, Martins, Duarte & Costa, Dimítri De Araújo, 2022, Checklist of water mites from mainland Portugal and its archipelagos, pp. 336-370 in Zootaxa 5213 (4) on page 358, DOI: 10.11646/zootaxa.5213.4.2, http://zenodo.org/record/7381432, {"references":["Walter, C. (1925) Hydracariens de l'Algerie et de la Tunisie (Collections de M. H. Gauthier), Premiere liste. Bulletin de la Societe d'Histoire Naturelle de l'Afrique du Nord, 16, 189 - 238.","Gerecke, R., Gledhill, T., Pesic, V. & Smit, H. (2016) Susswasserfauna von Mitteleuropa. Bd. 7 / 2 - 3. Chelicerata: Acari III. Band 7 / 2 - 3. Springer Spektrum, Heidelberg, Dordrecht, London and New York, pp. i - xi + 1 - 429. [http: // link. springer. com / 10.1007 / 978 - 3 - 8274 - 2689 - 5]","Lundblad, O. (1956) Zur Kenntnis sud- und mitteleuropaischer Hydrachnellen. Arkiv for Zoologi 10, 1 - 306, tafel LXXXIV.","Valdecasas, A. G. (1988) Lista sinonimica y bibliografica de las Hidracnelas (Acari, Hydrachnellae) de la Peninsula Iberica, Islas Baleares e Islas Canarias. Lista de la flora y fauna de las aguas continentales de la Peninsula Iberica. Publicacion no 5. Asociacion Espanola de Limnologia, Museo Nacional de Ciencias Naturales (CSIC), Madrid, 81 pp. [http: // www. limnetica. net / documentos / listas / Lista _ 5 _ Hidracnelas. pdf]"]}

Limnesia (Limnesia) arevaloi Viets, 1918 Synonyms: Limnesia granulosa Walter, 1931; Limnesia martianezi Lundblad, 1962 Type material: Holotype one female (Viets 1918), Syntypes deposited in SMF, catalogue numbers 45385-2009- VIE/193, 45386-2010-VIE/193, 45387-2011-VIE/193 (GBIF 2022). Type locality: Spain (GBIF 2022): Valencia (Valdecasas 1988; Viets 1918). Geographical distribution: Iberian Peninsula, Canary Islands, South France, Italy and North Africa (Gerecke et al. 2016). Distribution in Portugal: South: Estremadura (Valdecasas 1988), in Sintra-Monserrate Park and Palace (Lundblad 1956). Ecological notes: Freshwater, at temporary and small permanent waters (Gerecke et al. 2016; Viets 1918). Limnesia (Limnesia) atlantica Lundblad, 1941 Type material: Holotype one male NHRS-GULI000089977, one female Allotype NHRS-GULI000089978, and one nymph type NHRS-GULI000089979 deposited at NRM (Pers. comm., G. Lindberg). Type locality: Portugal: Madeira Island (Lundblad 1941b). Geographical distribution: Portugal: Madeira Island (Borges et al. 2008; Hughes et al. 1998; Lundblad 1941b). Distribution in Portugal: Madeira Island (Borges et al. 2008; Hughes et al. 1998). Ecological notes: Freshwater environment (Borges et al. 2008; Hughes et al. 1998). Limnesia (Limnesia) fulgida Koch, 1836 Type material: Unknown, possibly lost. Geographical distribution: Holarctic (Gerecke et al. 2016; Smit & Van der Hammen 2000). Distribution in Portugal: South: Alentejo, in Ribeira de Odivelas (Gerecke et al. 2016; Smit &Van der Hammen 2000). Ecological notes: At standing freshwaters; larvae parasites of Chironomidae and Sphaeroceridae dipterans (Gerecke et al. 2016); present in plants, such as Batrachium spp., Myriophyllum spp., and Nymphea spp. (Lundblad 1956). Limnesia (Limnesia) iberica Lundblad, 1954 Type material: Holotype one male deposited in NRM, Lundblad No. Präp. 4478 (Lundblad 1954); Paratype: One female, Lundblad No. Präp. 4479 (Lundblad 1956). Type locality: Portugal: Beira Alta, in Santa Comba Dão (Lundblad 1954, 1956). Geographical distribution: Portugal: Beira Alta, in Santa Comba Dão (Lundblad 1954, 1956). Distribution in Portugal: Centre: Beira Alta, in Santa Comba Dão (Lundblad 1954, 1956). Ecological notes: Freshwater, at slow-moderate motion streams, on a sandy substrate; present in Carex spp. plants (Lundblad 1956). Limnesia (Limnesia) maculata (Müller, 1776) Synonym: Hydrachna maculata Müller, 1776 (original designation) Type material: Unknown, possibly lost. Type locality: Denmark or Norway (Müller 1776). Geographical distribution: Holarctic (Gerecke et al. 2016). Distribution in Portugal: South: Alentejo, in Ribeira de Odivelas (Lundblad 1956). Ecological notes: Freshwater, at standing and temporary waters; present in plants, such as Batrachium spp., Myriophyllum spp., Nymphea spp. (Lundblad 1956); Deutonymph larvae parasites of insect-chironomids Trichoptera and Cladocera larvae (Böttger 1969; Gerecke et al. 2016). Limnesia (Limnesia) manubriata Walter, 1928 Type material: Syntypes deposited at NHMB two male catalogue numbers NMB-ACWA 2815 and 2816, two female 2813 and 2814 and a deuteronymph 2812. Type locality: Algeria, in Kabylie, Agoulmine Temjout; and Tunisia, in Ajim, Djerba Island (Walter 1928). Geographical distribution: Portugal and North of Africa (Lundblad 1956; Valdecasas 1988; Walter 1928). Distribution in Portugal: South: Estremadura (Valdecasas 1988), in Sintra-Monserrate Park and Palace (Lundblad 1956). Ecological notes: Freshwater, at standing environments (Lundblad 1956). Limnesia (Limnesia) walteri Migot, 1926 Type material: Syntypes: Deposited in SMF, catalogue numbers 45725-3914-VIE/210, 45724-3905-VIE/210, and 45723-3901-VIE/210 (GBIF 2022). Type locality: France: Banyuls-sur-Mer, Barrage de la Baillaury (Migot 1926), Spain (GBIF 2022). Geographical Distribution: Russia, Southwestern Europe from Portugal to Greece, and North Africa, including the Sahara desert (Gerecke et al. 2016). Distribution in Portugal: Centre: Beira Alta (Valdecasas 1988), in Santa Comba Dão, and Côa River, near 10 km to Vilar Formoso (Lundblad 1956). Ecological notes: In standing freshwaters, characteristic of remnant pools in streams (Gerecke et al. 2016), and can be found at an altitude of 50 m (Migot 1926); clear water, on a sandy bottom, present in plants, e.g. grasses, Carex spp., Juncus spp. and Myriophyllum spp. (Lundblad 1956).

Limnesia hesperia Lundblad, 1930 New record — 1/0/0, Saut Sonnelle, Inini River, 3.668227°N, 53.960857°W, 28 Sept. 2017. Distribution — Peru (Lundblad 1930), Paraguay (Lundblad 1941), Surinam (Besseling 1949), French Guiana (this study). Remarks. According to Viets (1954b) Besseling’s material from Surinam does not belong to this species. When compared with the description in Lundblad (1941) there are indeed differences in the setation of P4. However, Besseling’s material and illustrations (Besseling 1949) matches the original description of Lundblad (1930), and, therefore, we disagree with Viets (1954b)., Published as part of K, Harry Smit, Pešić, Vladimir, K & K, Simon Clavier, 2022, Water mites from French Guiana, with the description of 14 new species (Acari: Hydrachnidia), pp. 1119-1153 in Acarologia 62 (4) on page 1124, {"references":["Lundblad O. 1930. Sudamerikanische Hydracarinen. Zugleich Revision von E. Daday aus Paraguay beschriebenen Arten. Zool. Bidr. Uppsala, 13: 1 - 86.","Lundblad O. 1941. Die Hydracarinenfauna Sudbrasiliens und Paraguays. Erster Teil. Kungl. Svensk. Vetenskapsakad. Handling., (s. 3), 19: 1 - 183.","Besseling A. J. 1949. Watermijten uit Suriname. Tijdschr. Entomol., 91: 159 - 179. (in Dutch with German summary)","Viets K. 1954 b. Wassermilben aus dem Amazonasgebiet (Hydrachnellae, Acari). (Systematische und okologische Untersuchungen). Bearbeitung der Sammlungen Dr. R. Braun, Arau, und Dr. H. Sioli, Belem. Schweiz. Zschr. Hydrol., 16: 78 - 247. https: // doi. org / 10.1007 / BF 02483636"]}

Limnesia guianaensis Smit & Pešić sp. nov. Zoobank: 5F31FFDF-7DCA-457B-9F70-63D862939FE8 (Figures 2 A-D) Material examined — Holotype male, National Reserve La Trinité / Parc Amazonien de Guyane, Courcibo River, French Guinea, 4.475657°N, 53.219474°W, 14 Nov. 2019, leg. S. Clavier, dissected and slide mounted (MNHN). 100 µm, C = 50 µm., Published as part of K, Harry Smit, Pešić, Vladimir, K & K, Simon Clavier, 2022, Water mites from French Guiana, with the description of 14 new species (Acari: Hydrachnidia), pp. 1119-1153 in Acarologia 62 (4) on pages 1121-1122

Limnesia surinamensis Besseling, 1949 (Figures 3 A-D), Published as part of K, Harry Smit, Pešić, Vladimir, K & K, Simon Clavier, 2022, Water mites from French Guiana, with the description of 14 new species (Acari: Hydrachnidia), pp. 1119-1153 in Acarologia 62 (4) on page 1125, {"references":["Besseling A. J. 1949. Watermijten uit Suriname. Tijdschr. Entomol., 91: 159 - 179. (in Dutch with German summary)"]}

Limnesia (Limnesia) jolova Cook, 1986 New record — New South Wales. 2/0/0, Waterfall Creek at Gunulla Flat, Royal NP, 8 Nov. 2001. Distribution — Thus far known only from the holotype male collected in Queensland and reported here for the first time from New South Wales., Published as part of Smit, Harry, 2022, New records of water mites of the family Limnesiidae Thor from Australia (Acari: Hydrachnidia), with the description of seven new species, pp. 193-222 in Acarologia 62 (1) on page 201, DOI: 10.24349/yu9v-w0lf, http://zenodo.org/record/7160186, {"references":["Cook D. R. 1986. Water mites from Australia. Mem. Amer. Entom. Inst., 40: 1 - 568."]}

Limnesia (Limnesia) surroma Cook, 1986 New records — New South Wales. 0/1/0, Upper Minnamurra River, W of Robertson, 6 Nov. 2001; 1/3/0, Leather Barrel Creek at crossing with Alpine Way, Mt Kosciuszko NP, 36°31.559′ S 148°11.611′ E, 999 m a.s.l., 8 Dec. 2003 ; 1/0/0, Thredbo River at Thredbo Diggers Picnic Area, Mt Kosciuszko NP, 36°26.753′ S 148°25.487′ E, 1136 m a.s.l., 8 Dec. 2003; 6/9/1, Swampy Plains River at crossing with Alpine Way, Mt Kosciuszko NP, 36°23.121′ S 148°10.837′ E, 425 m a.s.l., 9 Dec. 2003 ; 1/1/0, Six Mile Creek, SE Forests NP, 10 Dec. 2003. Victoria. 0/1/0, Eurobin Creek downstream of Mt Buffalo NP entrance, 36°41.745′ S 146°51.453′ E, 293 m a.s.l., 10 Mar. 2008. Remarks — Cook (1986) stated that “it would not surprise me to have one or no pairs of glandularia incorporated into the anterior dorsal plate and either one, two or three on the posterior plate”. Indeed, the female from the Upper Minnamurra River has the posterior dorsal plate with one pair of glandularia incorporated. Distribution — Previously known from Victoria only and reported here for the first time for New South Wales., Published as part of Smit, Harry, 2022, New records of water mites of the family Limnesiidae Thor from Australia (Acari: Hydrachnidia), with the description of seven new species, pp. 193-222 in Acarologia 62 (1) on page 212, DOI: 10.24349/yu9v-w0lf, http://zenodo.org/record/7160186, {"references":["Cook D. R. 1986. Water mites from Australia. Mem. Amer. Entom. Inst., 40: 1 - 568."]}

Limnesia (Heterolimnesia) tasmanica (Lundblad, 1941) New records — Tasmania. 2/19/5, Reservoir of Darlington, Maria Island NP, 42°35′23.28” S 148°5′7.78” E, 18 Oct. 1997 ; 0/1/0, Apsley River at crossing with Tasman Highway, 19 Oct. 1997; 0/3/0, Swamp 12 km S of Gladstone, along road B82, 20 Oct. 1997 ; 0/1/0, Little Waterhouse Lake, Waterhouse Protected Area, 21 Oct. 1997 ; 0/1/0, Blackmans Lagoon, Waterhouse Protected Area, 21 Oct. 1997 ; 1/0/1, Nive River at crossing with A10, 42°09.456 S 146°28.130 E, 588 m a.s.l., 26 Mar. 2008 ; 1/1/0, Macquairy River at crossing with road C522, 41°54.472′ S 147°23.546′ E, 162 m a.s.l., 28 Mar. 2008. Victoria. 1/1/1, swamp at junction of Victoria Valley Road and Bundol Road, SW of Grampians NP, 37°35′14.50” S 142°18′58.36” E, 30 Sept. 1997 ; 7/21/1, pond along Buckland Valley Road, near crossing with Buckland River, W of Bright, 11 Oct. 1997. Distribution — Known from Tasmania, Victoria, South Australia and New South Wales., Published as part of Smit, Harry, 2022, New records of water mites of the family Limnesiidae Thor from Australia (Acari: Hydrachnidia), with the description of seven new species, pp. 193-222 in Acarologia 62 (1) on page 212, DOI: 10.24349/yu9v-w0lf, http://zenodo.org/record/7160186

Limnesia szalayi K. Viets, 1955 syn. nov. Material examined — Limnesia patens. Syntypes: Two males, three deutonymphs, Kratersee Telaga, Buitenzorg, Java, 21.11.1928, (Type, slide 45621, SMF); two males, one female, Sindanglaja Quelle, Buitenzorg, Java, 21.11.1928 (Types, slide 45622, SMF). Limnesia szalayi. Holotype female, Kuranda, N Queensland, Laird coll., 13.6.54 (slide 45696, SMF). New record — Queensland. 1/1/0, Spear Creek at crossing with Bypass Road, Cape York Peninsula, 12°03.206′ S 142°39.138′ E, 76 m a.s.l., 23 Oct. 2014. Remarks — The specimens from this study match the description of K. Viets (1935) well. K. Viets (1955) described a very similar species from northern Queensland, i.e. L. szalayi. The description of the latter species was based on one female only, and Viets didn′t compare it with other species. Moreover, the holotype of L. szalayi was fixed in ethanol, which makes it often difficult to see the morphological structures well. Cook (1986) noticed the similarity between the two species. When comparing the original descriptions, the only difference I find between the two species is that L. patens has no posteromedial platelet (K. Viets 1935), and in L. szalayi an indistinct platelet should be present (K. Viets 1955). I examined the holotype and only known specimen thus far of L. szalayi, but I do not see a posteromedial platelet. In the shape of palp and genital field the two species are identical. Therefore, I propose to synonymize L. szalayi with L patens. Distribution — Limnesia patens is widespread, and has been reported from Java, Indonesia (K. Viets 1935), India (Cook 1967) and Burma (Lundblad 1969). Within Australia known only from Queensland., Published as part of Smit, Harry, 2022, New records of water mites of the family Limnesiidae Thor from Australia (Acari: Hydrachnidia), with the description of seven new species, pp. 193-222 in Acarologia 62 (1) on page 205, DOI: 10.24349/yu9v-w0lf, http://zenodo.org/record/7160186, {"references":["Viets K. 1955. Kleine Sammlungen europaischer und aussereuropaischer Wassermilben (Hydrachnellae, Acari). Abh. naturw. Verein Bremen, 34: 1 - 26.","Viets K. 1935. Die Wassermilben von Sumatra, Java und Bali nach den Ergebnissen der Deutschen Limnologischen Sunda-Expedition. Arch. Hydrobiol., Suppl., 13: 484 - 594? 14: 1 - 113.","Cook D. R. 1986. Water mites from Australia. Mem. Amer. Entom. Inst., 40: 1 - 568.","Cook D. R. 1967. Water mites from India. Mem. Amer. Entom. Inst., 9: 1 - 411.","Lundblad O. 1969. Indische Wassermilben, hauptsachlich von Hinterindien. Ark. Zool., 22: 289 - 443."]}

Limnesia (Limnesia) ekama Cook, 1986 New records — Tasmania. 1/1/0, unnamed creek at crossing of Rosendale Road, 2.5 km off Tasman Highway, Bicheno, 19 Oct. 1997 ; 0/1/0, Betka River at crossing with Stony Creek Road, SW of Genoa, 24 Oct. 1997. Victoria. 2/3/2, Aire River at Aire Crossing, Great Otway Ranges NP, 38°42.190′ S 143°28.536′ E, 202 m a.s.l., 1 Apr. 2008. New South Wales. 0/1/0, tributary of Sawyers Creek, N of Kangaroo Valley, 6 Nov. 2001. Queensland. 0/1/0, Lacey Creek, Mission Beach, 17 Sept. 2000 ; 2/2/0, Babinda River, Wooroonooran NP, 17°20.484′ S 145°52.113′ E, 16 Oct. 2005 ; 1/0/0, Tully River at campground, Tully Gorge NP, 17°46.280′ S 145°39.073′ E, 86 m a.s.l., 4 Nov. 2014. Distribution — Previously known from Tasmania and New South Wales (Cook 1986) and reported here for the first time from Victoria and Queensland., Published as part of Smit, Harry, 2022, New records of water mites of the family Limnesiidae Thor from Australia (Acari: Hydrachnidia), with the description of seven new species, pp. 193-222 in Acarologia 62 (1) on page 196, DOI: 10.24349/yu9v-w0lf, http://zenodo.org/record/7160186, {"references":["Cook D. R. 1986. Water mites from Australia. Mem. Amer. Entom. Inst., 40: 1 - 568."]}

Limnesia (Limnesia) hopa Cook, 1986 (Figure 4) New records — Queensland. 0/1/0, Little Yabba Creek, hyporheic, at crossing with road Kenilworth-Maleny, 26°37.427′ S 152°41.334′ E, 98 m a.s.l., 19 Nov. 2014 ; 1/0/0, same location, 1 Dec. 2014 ; 0/1/0, Sandy Creek, W of Maleny, 26°42.241′ S 152°41.120′ E, 115 m a.s.l., 1 Dec. 2014. Description — Female: Idiosoma dorsally 494 long and 284 wide. Dorsum with two large plates, anterior plate with two pairs of glandularia and the postocularia, 184 long and 202 wide. Posterior dorsal plate with three pairs of glandularia, 292 long and 232 wide. Coxae in most aspects similar to male, except Cx-IV, these forming a genital bay (Figure 4). Genital field 136 long and 104 long, with three pairs of acetabula, the anterior pair distanced from the two posterior pairs. Length of P1-5: 28, 58, 44, 76, 30. Palp as in male. Length of I-leg-4-6: 82, 98, 82. Length of IV-leg-4-6: 92, 108, 103; subterminal seta of IV-leg-6 52 long. Legs without swimming setae. Remarks — Thus far, known from the holotype male only. Therefore, a description is given of the female. Distribution — Queensland., Published as part of Smit, Harry, 2022, New records of water mites of the family Limnesiidae Thor from Australia (Acari: Hydrachnidia), with the description of seven new species, pp. 193-222 in Acarologia 62 (1) on pages 200-201, DOI: 10.24349/yu9v-w0lf, http://zenodo.org/record/7160186, {"references":["Cook D. R. 1986. Water mites from Australia. Mem. Amer. Entom. Inst., 40: 1 - 568."]}

Limnesia (Limnesia) gledhilli sp. nov. Zoobank: 6B036679-A3D6-41B3-9406-413CE473335C (Figure 3 A-E) Material examined — Holotype male, Toolona Creek downstream of Toolona Falls, Lamington National Park, Queensland, Australia, 28°14′50.63” S 153°10′11.36” E, 16 Nov. 2003 (QM). Paratypes: one male, three females (QM), two males, three females (RMNH), same data as holotype ; 3 females, one deutonymph, Coomera River upstream of Coomera Falls, Lamington National Park, Queensland, Australia, 28°14′7.21” S 153°11′28.81” E, 14 Nov. 2003 (RMNH). Diagnosis — Idiosoma with extensive secondary sclerotization surrounding Cx-IV and genital field in male, posterior to Cx-IV in female; Cxgl-4 located on Cx-III close to associated seta. Male: Gonopore large, nearly as long as genital field; Cxgl-3 distanced from Vgl-1. Description — Male: Idiosoma dorsally 895 (919-936) long and 672 (689-725) wide, ventrally 842 (875-895) long. Integument coarsely lineated. Postocularia on small platelets. Dorsum with a relatively large posteromedial platelet (Figure 3A), 186 (194-198) long and 130 (120-134) wide. Gnathosomal bay shorter than fused portion of Cx-I. Cx-I fused medially. Cxgl-4 lying on Cx-III, close to associated seta (Figure 3B). Extensive secondary sclerotization surrounding Cx-IV, this sclerotization extending onto lateral margins of dorsum. Genital field 174 long and 184 wide, with three pairs of glandularia, surrounded by secondary sclerotization. Anterior acetabula elongated, posterior two pairs of acetabula more rounded. Gonopore large, nearly as long as genital field, 154 (154-164) long and 66 (64-76) wide. Cxgl-3 distanced from Vgl-1. Length of P1-5: 26, 110, 72, 154, 44. P2 ventrally with a relatively small peg-like setae (Figure 3C). Length of I-leg-4-6: 112, 132, 106. Length of IV-leg-4-6: 204, 202, 188. Terminal seta of IV-leg-6 102 long. IV-leg-5 with one long, stiff seta, and IV-leg-4 with two such setae (Figure 3D). III-leg-5 with 5-6 thin, relatively long setae along entire segment, these a little more than half the length of segment, which could act as swimming setae. Female: Idiosoma and integument as described for male, dorsally 883 (895-1000) long and 753 (721-778) wide, ventrally 867 (830-927) long. Dorsum with a posteromedial platelet, 190 (186-211) long and 130 (112-128) wide. Cx-I fused medially. Gnathosomal bay shorter than fused portion of Cx-I. Cxgl-4 lying on Cx-III, close to associated seta. Extensive secondary sclerotization surrounding Cx-IV, this sclerotization extending onto lateral margins of dorsum. Cxgl-3 incorporated in sclerotization, well distanced from Vgl-1 (Figure 3E). Genital field 178 long, pregenital sclerite 182 wide. Posterior to genital field a large platelet. Length of P1-5: 22, 134, 72, 155, 44. Palp as in male. Length of I-leg-4-6: 110, 130, 142 (till tip of segment). Length of IV-leg-4-6: 194, 194, 190; terminal seta of IV-leg-6 96 long. Legs as in male. Deutonymph. Idiosoma coarsely lineated, dorsally 551 long and 470 wide, ventrally 543 long. Along Cx-IV an indistinct small band of secondary sclerotization. Provisional genital field with two pairs of acetabula. P2 without peg-like setae. Etymology — Named after Terry Gledhill for working 60 years on water mites., Published as part of Smit, Harry, 2022, New records of water mites of the family Limnesiidae Thor from Australia (Acari: Hydrachnidia), with the description of seven new species, pp. 193-222 in Acarologia 62 (1) on page 198, DOI: 10.24349/yu9v-w0lf, http://zenodo.org/record/7160186

An illustrated description of male of a new species Limnesia mongolica sp. nov. from Dergun reservoir of Mongolia is given. The genital field with three pairs of small acetabula, distance between ac.1 and ac.2 two to three times larger than length of any acetabulum, distance between ac.2 and ac.3 equal or larger than length of any acetabulum; P-4 distally strongly curved, with two simple ventral setae near middle of segment.