Lebertia (Pilolebertia) iderensis, 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 : 485-487

Lebertia (Pilolebertia) iderensis sp. n.

( Figs. 1– 9 )

Holotype: female, slide 9944, Asia , West Mongolia, Ider stream, 48.635516, 99.044291, about 1100 m, depth 1.5 m, 22.08. 2016, leg. A. Prokin.

Diagnosis. Coxal shield longer than wide; coxal plates II with narrow posterior margin; genital field with 19–22 thin medial setae on each side; P-2 distoventral setae nearly twice shorter than ventral margin of segment, all dorsoproximal setae long and subequal in size; P-3 mediodistal seta near centre of the segment; P-4 slender with concave ventral margin, slightly tapering distally, ventral margin divided by seta insertions into sectors: 1: 1: 1; excretory pore not sclerotized, IV-Leg-6 with two short ventral setae.

Female. Colour in life unknown. Integument smooth. Setae Fch ( Fig.1 ) thicker than other idiosomal setae, trichobothria Fp, Oi and setae Pi not associated with glandularia ( Fig. 2 ), others idiosomal setae associated with glandularia ( Fig. 3 ).

Coxal plates I fused to each other nearly complete, short fragment of suture line present only in their posterior portion ( Fig. 4 ). Coxal plates I median length and suture line between coxal plates II and of nearly subequal in length (Cx-I/Cx-II ratio mL 1.03). Posterior margin of coxal plates II narrow. Coxal shield bearing two pairs of glandularia (Hv and Pe), Pe located near tips of coxal plates I. Coxal plates IV embracing the genital field to about 2/3 and forming right posteromedial corner on each side.

Genital field ( Fig. 4 , 6 ) with three pairs of acetabula, ac-1 and ac-2 relatively large, subequal in shape and size, posterior pair of acetabula smaller than both anterior pairs, genital flaps with 19–22 pairs of setae at medial margin, arranged in a single line, anterior genital sclerite with small posterior projection. Excretory pore not sclerotized.

Pedipalp slender ( Fig. 5 ): P-1 short, with single rather long dorsodistal seta; P-2 large, with concave ventral margin, three subequal dorsoproximal setae and two moderately long subequal dorsodistal ones, ventrodistal seta much shorter than ventral margin of segment, inserted away from ventrodistal edge of segment; P-3 thickened in distal half, with two anterior relatively short dorsoproximal and three long distal setae, distance between medio- and dorsodistal setae a little larger than distance between medio- and ventrodistal setae; P-4 slender, gradually tapering distally, dorsal setae concentrated to a longitudinal pit in distal portion of segment, ventral margin divided by seta insertions into sectors: 1: 1: 1, mediodistal peg-like seta moderately developed with rounded tip. Chelicera basal segment large, a little thickened near the middle of segment, chela short ( Fig.7 ).

Legs II–IV with swimming setae, their number as following: 8 on II-Leg-5, 6–7 on III-Leg-4, 8–11 on III-Leg-5, 8–9 on IV-Leg-4/5, IV-Leg-6 with two short pointed ventral setae ( Fig. 8 ). Leg claws with short internal and long external clawlets, lamella moderately developed with concave ventral margin, ( Fig. 9 ).

Measurements (n=1). Idiosoma L 1300; coxal shield L 875, W 850; coxal plate I/II mL 225, 215; coxal plate II posterior margin W 40; coxal plates I/II W 385/585; IV-Leg insertion W 850; capitular bay L 235, W 175; genital bay L 210; W 235; genital flap L 235, genital acetabula (ac-1–3) L 75–85, 68–75, 45–50; cheliceral segments L: base 300, chela 50; pedipalp segments (L/H, ratio, % total L): P-1, 36/60, 0.6, 6.4%; P-2, 162/84, 1.92, 29.4%; P-3, 126/66, 1.9, 22.9%; P-4, 172/48, 3.58, 31.3%; P-5, 54/24, 2,25, 9.8 %, proportions of pedipalp segments (L ratio): P-2/P-3, 1.28; P-2/P-4, 0.94; P-3/P-4, 0.73; P-3 distance between setae: a/b/c/d/e, L: 25/19/80/32/93; distance ratio mediodistal setae P-3 (a/b) 0.75; P-4 ventral sector, L 30%, 34%, 36%; pedipalp total L 550; P-4 mediodistal peg-like seta (L/H, ratio) 16/6.5, 2.46; leg segments (L/H, ratio): I-Leg-1,110/68, 1.61; I-Leg-2,125/87, 1.43; I-Leg-3,150/87, 1.72; I-Leg-4, 210/81, 2.59; I-Leg-5, 235/58, 4.05;I-L-6, 210/50, 4.20; II-Leg-1, 110/87, 1.26, II–Leg-2, -160/87, 1.83, II-Leg-3, 175/87. 2.01; II–Leg-4, 275/75, 3.66, II-Leg-5, 310/ 62, 5.0, II-Leg-6, 275/62, 4.43; III–Leg-1, 125/82, 1,52, III-Leg-2, 175/87, 2.01, III–Leg-3, 210/87, 2.41, III-Leg-4, 310/75, 4.13, III–Leg-5, 375/62, 6.04, III–Leg-6, 325/62, 5.24; IV-Leg-1, 225/112, 2.0, IV-Leg-2, 185/87, 2.12, IV-Leg-3, 275/87, 3.16, IV-Leg-4, 375/87, 4.31, IV-Leg-5, 400/87, 4.59, IV-Leg-6, 350/75, 4.66; proportions of leg segments (L ratio): IV-L-4/5, 0.93; IV-L-4/6, 1.07; IV-L-5/6, 1.14; IV-L claw, distance ab/ac/bc, L 80/74/48.

Male. Unknown.

Remarks. The present species is similar to L. porosa Thor, 1900 and L. obscura Lundblad, 1926 in the shape of coxal field and swimming setation of legs. Originally L. obscura has been described as “nov. var.” within the description of L. porosa . The most striking differences between named species are found in the formation of the hind leg segments, L. porosa having distinctly stouter segments, longer claws than in L. obscura , and also reveal a higher number of setae at the medial margins of genital flaps of L. porosa (Tyokosová et al. 2020.).

Differences between the Lebertia iderensis sp.n. and L. porosa in the following characters (character states of L. porosa are given in parenthesis, data from Tyokosová et al. 2020): the pedipalp slender, Fig. 5 (comparative compact, Fig. 10 ); P-2 ventrodistal seta almost two times shorter than ventral margin of segment (subequal in length or it a little shorter than ventral margin of segment), P-2 all dorsoproximal setae long and subequal in length (anterior dorsoproximal seta much shorter than others dorsoproximal ones), P-4 ventral sectors almost subequal in length, 30%, 34%, 36% (P-4 ventral sectors unequal in length, 47–48%, 33–38%, 15–19%).

The male of L. obscura characterized by short leg claws (IV-Leg L 43–55), P-4 ventral sectors, 37–55%, 34–38%, 17–27%, while in L. iderensis sp.n. leg claws comparatively large, IV-Leg L 80.

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

Habitat. Running waters.

Distribution. Asia, West Mongolia.

Figures

FIGURES 1–5. Lebertia iderensis sp. n., male: 1, seta Fch; 2, seta Oi; 3, seta Oe; 4, ventral view; 5, pedipalp. Scale bars: 1–3, 4 =100 μm, 5 = 50 μm.

FIGURES 6–10. Lebertia species; FIGURES 6–9. Lebertia iderensis sp. n., male: 6, genital field; 7, chelicera, lateral view; 8, IV-Leg-4–6; 9, leg claw. Scale bars: 6 = 100 μm, 7, 9 = 50 μm, 8 = 200 μm. FIGURE 10. Lebertia porosa Thor, 1900, female: 10, pedipalp (from Tyokosová et al. 2022). Scale bar: 100 μm.