Hygrobates lacrima Pešić, 2020

Pešić, Vladimir, Jovanović, Milica, Ana, Manović, Zawal, Andrej, Bańkowska, Aleksandra, Broda, Łukasz, Martin, Peter & Dabert, Miroslawa, 2020, Two new species from the Hygrobates nigromaculatus-complex (Acariformes, Hydrachnidia, Hygrobatidae), based on morphological and molecular evidence, Acarologia 60 (4), pp. 753-768 : 756-760

Hygrobates lacrima Pešić sp. nov.

Zoobank: 107B544E-3B5E-41BA-96BB-4D2F2F967F5E

Figs. 3 , 4 , 5 A-B

Material examined — Holotype ♀ [27. CG2020 _3_C7], sequenced, dissected and slide mounted, Montenegro, River Tara near Mateševo, 42°47 ′ 18.78 ″ N, 19°32 ′ 20.71 ″ E, 26.10.2019, leg. Pešić. Paratypes: 1♂, 2♀♀ (1♂ and 1♀ partially dissected [palp, I-L and IV-L from one side slide mounted], River Tara near Trebaljevo, 42°51 ′ 47.68 ″ N, 19°31 ′ 37.30 ″ E, 1.9.2019, leg. Pešić.

Diagnosis — Large in size (mL of Cx-I + gnathosoma ˃ 340, L genital plate ˃ 210, P-4

˃ 170 μm); Cx-I+II apodemes protruding in both sexes, in females mediocaudal margins of Cx-IV with well-developed apodemes; anterior margin of male genital field with a bluntly pointed medial projection; L of IV-L-6 proximoventral seta ♂ ˂ 20, ♀ ˂ 35 μm.

Description — General feature – Colour yellowish to brown. Integument finely striated. Posteromedial margin of Cx-I rounded, caudal apodemes of Cx-I+II well-developed ( Figs. 3A , 4A ); Cx-IV subtriangular, with a distinct nose-like protruding medial margin. Genital field (in female holotype slightly damaged during dissection and mounting): Ac in triangular arrangement ( Figs. 5 A-B). P-2 ventral margin straight, distally forming a right angle, denticles covering distal half of ventral margin; P-3 with denticles covering distal two thirds of ventral margin; P-4 ventral setae on the same level ( Figs. 3 B-C, 4B).

Male – Anterior margin of genital field convex, with a small bluntly pointed medial projection, posterior margin indented, with a small central protrusion not extending beyond posterior genital plate margin ( Fig. 5A ).

Female – Genital plates distinctly longer than gonopore ( Fig. 5B ); P-4 slenderer than in male, L/H ratio 4.2-4.5.

Measurements — Female (holotype; in parentheses measurements of paratype from Trebaljevo, Montenegro, n = 1)

Idiosoma – L (1025), W (944); coxal field: L 481 (506); Cx-II W 458 (485); Cx-III W

600 (653); mL of Cx-I + gnathosoma L 344 (361); distance between lateralmost ends of Cx-II apodemes, 191 (212); genital field L/W 219/294 (244/345); genital plate L 219 (241-248);

gonopore L (203); L gonopore/genital plate ratio (0.82-0.84); L Ac 1-3: 119 (119-125), 128

(108-123), 95-113 (81-84).

Palp – total L 549 (623); dL/H, dL/H ratio: P-1, 44/50, 0.88 (52/53, 0.97); P-2, 147/89, 1.65

(161/98, 1.64); P-3, 99/77, 1.29 (122/82, 1.49); P-4, 192/45, 4.24 (217/48, 4.48); P-5, 67/23,

2.9 (71/29, 2.4); P-2/P-4 ratio 0.77 (0.74).

Legs – dL of I-L-1-6: 92 (95), 116 (141), 164 (184), 241 (259), 242 (272), 247 (266). dL

of IV-L-1-6: 173 (188), 180 (200), 284 (328), 397 (438), 394 (441), 350 (364); L of IV-L-6

proximoventral seta 34 (23).

Male (paratype from Trebaljevo, Montenegro, n = 1)

Idiosoma – L 875, W 680; coxal field: L 477; Cx-II W 428; Cx-III W 577; mL of Cx-I + gnathosoma L 350; distance between lateralmost ends of Cx-II apodemes, 197; genital field L/W 231/300, ratio 0.77; L Ac 1-3: 106-119, 97-100, 106-115.

Palp – total L 511; dL/H, dL/H ratio: P-1, 41/47, 0.87; P-2, 134/86, 1.56; P-3, 95/70, 1.35;

P-4, 177/42, 4.2; P-5, 64/22, 2.9; P-2/P-4 ratio 0.76.

Legs – dL of I-L-1-6: 78, 109, 147, 213, 231, 216. dL of IV-L-1-6: 150, 166, 263, 378,

362, 314; L of IV-L-6 proximoventral seta 18.

Etymology — “ lacrima ” (Latin): tear, in reference to the name of Tara River – The Tear of Europe.

Remarks — Based on molecular analysis, Hygrobates lacrima sp. nov. is closely related to H. nigromaculatus . The distance between these two species was 15.87% (SD = 1.74) K 2P.

In comparison with the new species from Montenegro, H. nigromaculatus (data taken from Martin et al. 2010) generally is smaller in dimensions. In males of H. nigromaculatus , the length of genital plate is ˂ 160 vs (. ˃ 220 μm in H. lacrima ), in females ˂ 175 (vs. ˃ 210 μm

in H. lacrima ); mL Cx-I + gnathosoma in males is ˂ 280 (vs. ˃ 340 μm in H. lacrima ), in females ˂ 350 μm (vs. ˃ 340 μm in H. lacrima ); the length of P- 4 in males H. nigromaculatus is ˂ 130 (vs. ˃ 160 μm in H. lacrima ), in females ˂ 165 μm (vs. ˃ 180 μm in H. lacrima ). Moreover, the species live in different habitats: H. nigromaculatus in lakes, whereas H. lacrima inhabits pools and shallow eddies along faster flowing waters (see Figs. 9 A-C). From H.

setosus (in parentheses, based on material from Farver Au, Germany), male of new species differs in having the bluntly-pointed medial projection of the genital field and comparatively wider genital field (L/W ratio 0.83-0.9; compare Fig. 5A and 5G ). Although Tuzovskij (2017) showed different types of male genital plates for H. nigromaculatus , we cannot exclude that he dealt with several species. Therefore, we think that the differences between the male genital plates of H. lacrima and other species as given in the key are justified.

Due to its larger size and habitat preference for running waters, the new species is similar to H. limnocrenicus sp. nov. (see there for further discussion).

Distribution — Montenegro; know from two localities along the middle course of the Tara River ( Figs. 9 A-C). These two sites were subject of a monthly monitoring survey in 2019 on the river biota of the Tara River during the Bar-Boljare highway development activities (see Pešić et al. 2020a). At the Mataševo site, only one specimen (which was successfully barcoded) was collected, probably due to the negative ecological impact associated with highway development activities in the immediate vicinity (for the controversy surrounding highway construction over the Tara River see Pešić et al. 2020b). At the Trebaljevo site located downstream, the negative impact was less pronounced - here, three individuals were collected.

Figures

Figure 3 Hygrobates lacrima sp. nov., holotype ♀, Mateševo, Montenegro: A – idiosoma, ventral view; B – palp, lateral view; C – palp, medial view; D – chelicera; E – I-L-5 and -6; F – IV-L-5 and -6. Scale bars = 100 µm.

Figure 4 Hygrobates lacrima sp. nov., ♂. Montenegro, Trebaljevo: A – idiosoma, ventral view; B – palp, medial view; C – IV-L-5 and -6. Scale bars = 100 µm.

Figure 5 Genital field: A-B –Hygrobates lacrima sp. nov., paratypes (A, ♂; B, ♀), Trebaljevo, Montenegro; C-F –Hygrobates limnocrenicus sp. nov. (C-D, F, ♀; E, ♂); C, holotype, Mareza, Montenegro; D, paratype, Struga, North Macedonia; E-F, Vitoja, Montenegro; G-HH –. setosus Besseling, 1942, ♂, G, Farver Au, Germany; H, redrawn from Besseling (1964).

Figure 9 Sampling sites: A-B – River Tara near Trebaljevo; C – River Tara near Mateševo; D – the ”Kraljičino Oko” (the Queen’s Eye) spring near Podgorica; E – River Crni Drim near Struga; F – the Vitoja spring located on the north-eastern shore of Lake Skadar flooded in the winter and spring months.