Lebertia (Pilolebertia) mongolica, Tuzovskij, 2022

Tuzovskij, Petr V., 2022, Two a new water mite species of the genus Lebertia Neuman, 1880 (Acari, Hydrachnidae: Lebertiidae) from Mongolia, Zootaxa 5195 (5), pp. 485-491 : 488-491

Lebertia (Pilolebertia) mongolica sp. n.

( Figs. 11–20 )

Holotype: male, slide 9948, Asia, West Mongolia , Orkhon reservoir, depth 1.5 m, 01.09.2017, leg. A. Prokin.

Diagnosis. Integument finely striated, seta Fch short, thick serrate; coxal shield wider than long, ml of coxal plates I/II equal in length, genital flap with 31–35 medial and 6–7 lateral setae each; P-2 ventrodistal seta long but not exceeding total length of segment; P-3 distance between mediodistal and dorsodistal setae a little smaller than distance between mediodistal and ventrodistal setae; P-4 ventral sectors 3:2:1, mediodistal seta short, thin; IV-Leg-6 with two short, thick ventral setae.

Description. Male. Colour in life unknown. Integument soft and finely striated. Setae Fch ( Fig. 11 ) short serrate and much thicker than others idiosomal setae. Trichobothria Fp, Oi and setae Pi not associated with glandularia ( Fig. 12 ), other idiosomal setae associated with glandularia ( Fig. 13 ). Coxal shield ( Fig. 14 ) wider than long (L/W ratio 0.94), medial length of coxal plates I and suture line between coxal plates II subequal in length. Coxal plates I fused to each other nearly complete, fragment of suture line present only in their posterior portion. Posterior margin of coxal plates II narrow. Capitular bay deep U-shaped, genital bay comparatively short and a little wider than long.

Pedipalp slender ( Fig. 15 ): P-1 short, with single dorsodistal seta; P-2 large, with concave ventral margin, ventrodistal seta inserted close to ventrodistal edge, longer than ventral margin but shorter than total length of segment, anterior dorsoproximal seta shorter than both others dorsoproximal setae, both dorsodistal setae equal in length and longer than dorsoproximal ones; P-3 slender slightly thickened distally, both dorsoproximal setae distinctly separated; distance between mediodistal and dorsodistal setae a little smaller than distance between mediodistal and ventrodistal setae; P-4 slender a little thickened in proximal part, gradually tapering distally, with concave distal end, ventral setae inserting in the distal half of segment and dividing segment into three sectors 3:2:1, mediodistal seta short, thin situated in distal cavity.

Genital field ( Figs 14 , 16 ) with three pairs of acetabula, anterior two pairs subequal in length and large than posterior pair, flaps with 31–35 medial and 6–7 lateral setae each; pregenital sclerite small triangular with straight posterior margin, postgenital sclerite much broadly than anterior one. Excretory pore unsclerotized.

Capitulum with short rostrum, ventral margin strongly convex ( Fig.17 ). Chelicera basal segment large, narrowed proximally and thickened in distal half; chela short sickle-shaped ( Fig.18 ).

Legs II–IV with swimming setae, their number as following: six to seven on II-Leg-5 and IV-Leg-4, five to seven on III-Leg-4, 10–12 on III-Leg-5, eight to nine on IV-Leg-5; IV-Leg-6 with two short, thick ventral setae ( Fig. 19 ). Leg claws with short internal and comparatively long external clawlets, lamella moderately developed with slightly concave ventral margin ( Fig. 20 ).

Measurements (n=1). Idiosoma L 1180; coxal shield L 835, W 890; coxal plate I mL 185, coxal plate II mL 185; coxal plates II posterior margin W 30; coxal plates I, II W 362, 525; IV-Leg insertion W 800; capitular bay L 200, W 150; genital bay L 200, W 215; genital flap L 210, W 80, genital acetabula (ac-1–3) L 80, 75, 50; pedipalp segments (L/H, ratio, % total L): P-1, 35/55, 0.63, 7.74%; P-2, 130/66, 1.95, 27.74%; P-3, 125/54, 2.33, 27.10%; P-4, 145/48, 3.0, 30.96%; P-5, 30/18, 1.66, 6.46%; proportions of pedipalp segments (L ratio): P-2/P-3, 1.02; P-2/P-4, 0.89; P-3/P-4, 0.87; P-3 distance between setae a, b, c, d, e, L: 26, 19, 83, 32, 90; distance ratio mediodistal setae P-3 (a/b) 1.33; P-4 ventral sectors, 55%, 31%,14%; pedipalp total L 465; leg segments L/H, ratio: I-Leg-1, 85/62, 1.37, I-Leg-2, 110/75, 1.46, I-Leg-3, 110/62, 1.77, I-Leg-4, 150/56, 2.67, I-Leg-5, 150/50, 3.0, I-Leg-6, 155/37, 4.19; II-Leg-1, 100/62, 1.77, II-Leg-2, 110/80, 1.37, II-Leg-3, 125/75, 1.66, II-Leg-4, 210/75, 2.80, II-Leg-5, 250/62, 4.03, II-Leg-6, 225/62, 3.62; III-Leg-1, 125/87, 1.43, III-Leg-2, 150/81, 1.85, III-Leg-3, 160/75, 2.13, III-Leg-4, 275/75, 3.66, III-Leg-5, 325/62, 5.24, III-Leg-6, 285/75, 3.80; IV-Leg-6, 200/112, 1.78, IV-Leg -2, 165/87, 1.89, IV-Leg-3, 225/87, 2.58, IV-Leg -4, 300/75, 4.00, IV-Leg-5, 350/62, 5.64, IV-Leg-6, 325/75, 4.33; proportions of segments (L ratio): IV-Leg-4/5, 0.85; IV-Leg-4/6; IV-Leg-5/6, 1.07; IV-Leg claw, distance ab, ac, bc, L: 73, 67, 51.

Female. Unknown.

Differential diagnosis. The new species is similar to Lebertia longiseta Bader, 1955 and L. gibbosa Lundblad, 1926 ; however, the following clear differences can be found in the morphology of males (character states of L. longiseta are given parenthesis after Bader 1955, K.O. Viets 1976, Gerecke 2009, Di Sabatino et al. 2010): male: the idiosoma large, L 1180 (comparative small, L 900); the coxal shield wider than long, L/W 835/890, Fig. 14 (longer than wide, L/W 665–720/ 660–688, Fig. 21 ); the genital flaps large, L 210, with more than 30 medial setae each (relatively small, L 165–178, with 20 medial setae each); P-2 distoventral seta shorter than total length of segment, Fig. 15 (much longer than total length of segment, Fig. 22 ), P-2–P-4 rather large, L/H 130/66, 125/54, 145/48 (comparative small, L/H 92–99/62–69, 100–109/44–45, 115–127/35–38); P-4 mediodistal seta thin (relatively thick, Fig. 23 ).

The male of L. gibbosa characterized by the following characters: coxal shield longer than wide, Fig. 24 ; L IV-L-4–6 <260, 290, 260); coxal shield L 740; P-2 short (L 90–105), distoventral seta longer than total length of segment (about 110, Fig. 25 ); P-3 mediodistal seta P-3 away from dorsodistal seta (L ratio sectors a/b 1.7–1.8); P-4 ventral sectors 63 %, 28 %, 9 %; palp total L 384; IV-Leg claw L 50.

Etymology. The species is named after the name of the country ( Mongolia) where it was collected.

Habitat. Running waters.

Distribution. Asia, West Mongolia.

Figures

FIGURES 11–15. Lebertia mongolica sp. n., male: 11, seta Fch; 12, seta Oi; 13, seta Oe; 14, ventral view; 15, pedipalp. Scale bars: 11–13, 15 = 50 μm; 14 = 100 μm.

FIGURES 16–20. Lebertia mongolica sp. n., male: 16, genital field; 17, capitulum, lateral view; 18, chelicera, lateral view; 19, IV-Leg-4–6; 20, leg claw. Scale bars: 16–19 = 100 μm, 20= 50 μm.

FIGURES 21–25. Lebertia species; FIGURES 21–23, Lebertia longiseta Bader, 1955: 21, ventral view; 22, pedipalp; 23, P-4/5 (detail). FIGURES 24–25. Lebertia gibbosa Lundblad, 1926: 24, ventral view; 25, pedipalp; 21–22 from K.O. Viets (1976); 23, from Gerecke (2009); 24–25, from Tyokosová et al. (2022).