Hygrobates (Hygrobates) ponticu, Pešić, Vladimir, Esen, Yunus, Gerecke, Reinhard, Goldschmidt, Tom, Mumladze, Levan, Smit, Harry & Zawal, Andrzej, 2022

Pešić, Vladimir, Esen, Yunus, Gerecke, Reinhard, Goldschmidt, Tom, Mumladze, Levan, Smit, Harry & Zawal, Andrzej, 2022, Evidence of cryptic speciation in the Hygrobates calliger complex (Acariformes, Hydrachnidia, Hygrobatidae) with the description of two new species, Ecologica Montenegrina 59, pp. 101-122 : 117-120

Hygrobates (Hygrobates) ponticu s Pešić, Esen & Mumladze sp. nov.

https://zoobank.org/ urn:lsid:zoobank.org:act:23CF87A9-01BB-459A-9A76-C3884E3718EA

Figures 10-11

Material examined — Holotype ♀ ( RMNH), dissected and slide mounted [sequenced; BOLD /GenBank: HYDME054-22 /OP620941; voucher code: CCDB 41823 E06], Türkiye, Bingöl Province, Capakcur stream, 38.8936 N, 40.4772 E, 1147 m asl., 28 May 2021, leg. Esen. Paratypes: 1♀ [sequenced; BOLD /GenBank: NOVMD004-21 /OP620935; voucher code: CCDB 41822 A04], Georgia, Saghamo , 41.304 N, 43.7586 E, 1999 m asl., 13 May 2016, leg. Mumladze, Japoshvili, Bikashvili & Shubitidze, one palp dissected and slide mounted ( RMNH) ; 1♂ [sequenced; BOLD /GenBank: NOVMD076-21 /OP620933; voucher code: CCDB 41822 G04], Georgia, Saghamo , 41.304 N, 43.7586 E, 1999 m asl., 30 July 2016, leg. Mumladze, Japoshvili, Bikashvili & Shubitidze, dissected and slide mounted ( RMNH) .

Diagnosis — Dorsal lines interspace 5-8; P-2 with triangular, bluntly pointed, comparatively shortened (L/W ratio about 1.0) ventrodistal projection. Anterior margin of genital field with a very shallow indentation and a small knob-shaped medial projection in the centre of indentation; Ac-2 and Ac-3 placed next to each other; Ac-3 subtriangular; female gonopore longer than the genital plates.

Description. General Features — Colour yellow to brown. Integument soft, strongly lineated. Posteromedial margin of Cx-I+II obtuse-triangular, caudo-lateral apodemes of Cx-I+II moderately developed; Cx-IV subtriangular, with a distinct nose-like protruding medial margin ( Figure 10A ). Acetabula in triangular arrangement. P-2 ventral margin proximally concave, distally forming a triangular, bluntly pointed projection covered by small, scattered denticles; P-3 with denticles covering distal two thirds of ventral margin; P-4 ventral setae separated ( Figures 10B, D ). Male — Anterior margin of genital field with a very shallow indentation and a small knob-shaped medial projection in the centre of indentation, genital plate typically with an irregular margin of secondary sclerotization, posterior margin of genital field deeply indented with a small protrusion in the centre of indentation, not extending beyond posterior margin, Ac-2 and -3 placed next to each other, Ac-3 subtriangular ( Figure 10C ). Female — Genital plates with a narrow border of porose secondary sclerotization, gonopore longer than genital plates ( Figure 10A ); P-4 more slender than in male.

Measurements. Female (holotype; in parentheses some measurements of paratype from Georgia [CCDB 41822 A04]) — Idiosoma L 850 (1090), W (840); coxal field: L 384 (381); Cx-III W 483 (544); mL of Cx-I + gnathosoma 315 (306); distance between lateralmost ends of caudo-lateral Cx-II apodemes 147 (153); genital field L/W 209 (250)/236 (303); genital plates L 122-141 (141-144); pregenital sclerite W 90 (103); gonopore L 163 (213); L Ac 1-3: 50-56 (53-56), 59-68 (69-73), 56-59 (66-69). Egg maximum diameter (n = 1) (186).

Chelicera total L 323, L basal segment 244, claw 109, L basal segment/claw ratio 2.2. Palp: total L 497 (548); dL/H, dL/H ratio: P-1, 34/41, 0.83 (39/47, 0.84); P-2, 127/84, (139/91, 1.5); P-3, 105/77, 1.37 (113/78, 1.44); P-4, 172/39, 4.4 (198/44, 4.5); P-5, 59/22, 2.75 (59/20, 2.9); P-2/P-4 ratio 0.74 (0.7); P-4 ventral setae distance 32.

Legs: dL of I-L-1-6: 68, 94, 100, 163, 169, 159; L of longest I-L-6 distoventral seta 56; L distoventral seta/I-L-6 ratio 0.35; dL of IV-L-1-6: 138, 131, 175, 253, 277, 244.

Male (paratype [CCDB 41822 G04]) — Idiosoma L 960; coxal field: L 394; Cx-III W 525; mL of Cx-I + gnathosoma 306; distance between lateralmost ends of caudo-lateral Cx-II apodemes 128; genital field L/W 163/213, ratio; L Ac 1-3: 63-65, 74-75, 78-81. Ejaculatory complex L 148.

Chelicera total L 263. Palp: total L 480; dL/H, dL/H ratio: P-1, 39/45, 0.86; P-2, 120/78, 1.54; P-3, 106/73, 1.44; P-4, 163/38, 4.3; P-5, 52/19, 2.75; P-2/P-4 ratio 0.74; P-4 ventral setae distance 23.

Legs: dL of I-L-1-6: 69, 91, 106, 172, 178, 169; L of longest I-L-6 distoventral seta 58; L distoventral seta/I-L-6 ratio 0.34; dL of IV-L-1-6: 149, 138, 181, 259, 290, 250.

Etymology — Named after its distribution in the region around the Black Sea.

Discussion — Molecular analysis reveals a high interspecific distance between Hygrobates ponticus sp. nov. and the European clades of the H. calliger species complex. Morphologically, it resembles most closely European clade 1. The analysed specimens of the latter clade differ from the new species by a comparatively wider male genital plate, a shortened P-2 ventrodistal projection (L/W ratio ˂1.0) and a slightly more slender P- 4 in both sexes.

The molecular analysis based on COI data placed the specimens of Hygrobates ponticus sp. nov., as most similar to a clade containing specimens of H. quanaticola from southeastern Türkiye with a genetical distance of 21.0±2.0% K2P between these two species. Hygrobates quanaticola belongs to the polyacetabulate subgenus Rivobates , characterized by the genital field with more than three, often numerous pairs of acetabula. It was originally described from Iran ( Schwoerbel & Sepasgozarian 1976), and later on reported from Türkiye ( Erman et al. 2010); a redescription is given by Moradifaradonbeh et al. (2015).

Distribution — Türkiye (Bingöl Province), Georgia.

Figures

Figure 10. Hygrobates ponticus sp. nov. (A-B, ♀ holotype CCDB 41823 E06, Capakcur stream, Türkiye; C-D, ♂ paratype CCDB 41822 G04, Saghamo, Georgia): A – genital and coxal field; B, D – palp, medial view (inset: P-2 ventrodistal projection, 2x enlarged); C – genital field. Scale bar = 100 μm.

Figure 11. Hygrobates ponticus sp. nov., ♀ holotype CCDB 41823 E06, Capakcur stream, Türkiye: A – I-leg; B – IV- L-5 and -6. Scale bar = 100 μm.