Lebertia (Lebertia) cylinderia Wang & Guo, 2016

Wang, Jialin, Jin, Daochao, Yi, Tianci & Guo, Jianjun, 2016, Water mites of subgenus Lebertia (Lebertia) Neuman from China (Hydrachnidia: Lebertiidae), Zoological Systematics 41 (1), pp. 54-63 : 57-59

3.2 Lebertia (Lebertia) cylinderia Wang & Guo , sp. nov. ( Figs 8–15 )

Diagnosis. Idiosoma round in outline, integument with long lines at the dorsal surface ( Fig. 12 ). P-3 with 2 dorsal setae inserted proximally. P-4 cylinderical in outline ( Fig. 10 ). Medial suture Cx-I and Cx-II nearly equal in length, posterior margin of Cx-II 40 in width. IV-L-6 without dorsal seta, low number or no swimming setae on legs ( Fig. 15 ).

Description. Male. Idiosoma ( Figs 8–9 ). Color yellowish-brown. Idiosoma round in outline, 973–980 long and 824–840 wide.Integument with long lines on dorsal surface. Gf 197–240 in length and 130–167 in width. Acetabula 3 pairs, first pair 50–55 in length, second 50–58 in length, third 38–45 in length ( Fig. 13 ). Coxal plates single group, 580–677 in length and 550–609 in width; Medial suture Cx-I and Cx-II nearly equal in length, Cx-I ML 138–185, Cx-II ML 125–170, Cx-I/Cx-II ML ratio 1.08–1.10, posterior margin of Cx-II 38–40 in width, suture lines between Cx-III and Cx-IV reaching to inner 1/2 of plate; Cx-IV with obtuse posteromedial angels at both lateral sides behind genital field. Ib-Gf 300–350; Ib-Ap 700–761. Ib U-shaped, depth 150–175, width 80–84. Excretory pore smooth. Ventral margin of gnathosoma smooth, Gnathosoma length 188–225, chelicera length 225–264 ( Fig. 11 ).

Palp ( Fig. 10 ). P-2 with 5 setae, of which 2 dorsodistal setae long and thin, 2 dorsal setae much shorter and peg-liked, ventral seta as long as ventral length in L, inserted at 4/5 of segment. P-3 with 5 setae, ventrodistal seta slightly away from ventrodistal segment edge (distance about 12.5–14) and elongated (can surpass tip of P-5), mediodistal seta inserted close to dorsodistal seta (distance of insertions about 6–8); dorsal setae inserted proximally, separated from each other (distance about 16.5–19). P-4 cylindrical in shape with maximum H in proximal and terminal parts, ventral seta insertions divided ventral margin into 2: 3: 3. Dorsal length/height of palp segments: P-1, 38–40/40–43 (ratio 0.93–0.95); P-2, 88–102/55–72 (ratio 1.42–1.6); P-3, 88–105/44–46 (ratio 1.96–2.28); P-4, 100–121/33–34 (ratio 3.03–3.56); P-5, 34–35/18–19 (ratio 1.79–1.94). Total length of palp, 349–397.

Legs ( Figs 14–15 ). I-L-3 with 12 setae.I-L-4 with 2 dorsal setae and 1 ventral seta; I-L-5 with 3 dorsal setae and 1 ventral seta. I-L-6 with 5 ventral setae and 2 dorsal setae. IV-L-3 bearing 2 dorsal setae and 3 dorsal setae on segment. IV-L-4 with 2 dorsal setae and 3 ventral setae. IV-L-5 with 3 dorsal setae and 4 ventral setae. IV-L-6 bearing 3 setae, of which 2 dorsal setae small and short, 1 dorsodistal seta strong and elongated. Length/height of legs: I-L-3, 90–118/48–60 (ratio 1.88–1.97); I-L-4, 130–159/48–55 (ratio 2.70–2.89); I-L-5, 138–173/45–50 (ratio 3.07–3.46); I-L-6, 125–133/38–49 (ratio 2.71–3.29); IV-L-3, 158–183/48–68 (ratio 2.69–3.29); IV-L-4, 205–248/45–59 (ratio 4.10–4.20); IV-L-5, 225–287/45–54 (ratio 5.00–5.31); IV-L-6, 200–266/45–55 (ratio 4.44–4.84). Numbers of peg-like setae on IV-L-3–6: IV-L-3, 6; IV-L-4, 8; IV-L-5, 5. No swimming seta on legs.

Female. Unknown.

Material examined. Holotype, male, Hanasi Lake, Xinjiang, China (47°14.59'N, 87°12.97'E; elev. 1 374 m), coll. Daochao Jin, 13 August 1997, dissected and slide mounted in Koenike fluid, slide number XJ-IV-1997081301. Paratypes: 3 males, slide number XJ-IV-1997081302, XJ-IV-1997081303 and XJ-IV-1997081304, same data as holotype .

Etymology. “ cylinder ” means “tube-shape things”. The new species is named after the cylindrical shape in P-4.

Habitat. River, lake and stream.

Distribution. Palaearctic Region ( China (Xinjiang )).

Remarks. This new species is similar to Lebertia (Lebertia) sparsicapillata Thor, 1905 from Germany in the following points: 1) the medial sutures of Cx-I/II are similar in length (Cx-I/II ML ratio 0.9–1.3) ( Fig. 8 ); 2) The uniform shape of P-4 and the ventral setae on IV-L-6 ( Figs 10, 15 ). But the new species can be distinguished from the later by the following: 1) III-L-5 with 1–2 and IV-L-5 with 2 swimming setae in L. sparsicapillata, while the new species without swimming seta on legs; 2) IV-L-6 of L. sparsicapillata with 2–3 dorsal setae while the new species without ( Fig. 15 ); 3) P-2 of L. sparsicapillata with 1 smooth ventral seta, but P-2 of L. cylinderia with 1 clearly pectinated ventral seta: 4) the genital flap much smaller in L. sparsicapillata (Gf: 160–190 in males, 190–210 in females, while in the new species Gf 197–240 in male).The data of L. sparsicapillata is from Gerecke (2009).

The new species is also compared with L. (L.) subtilis Koenike, 1902 from Alps which is similar to the new species by having a low number of ventral setae on IV-L-6 and no swimming seta on legs. There are significant differences between these 2 species: 1) the genital field of L. subtilis with high number of medial setae (about 50 on each flap) while the new species with only 6 pairs of setae on the genital flaps ( Fig. 13 ); 2) medial suture Cx-I much longer than Cx-II of L. subtilis (Cx-I/II ML ratio 1.54 in L. subtilis ) while the medial suture of Cx-I and Cx-II are similar in length in the new species ( Fig. 8 ): 3) ventral seta of P-2 of L. subtilis inserted at the distal edge, while the ventral seta inserted slightly away from the distal edge, but at 4/5 of the segment in the new species ( Fig. 10 ). The data of L. subtilis is from Gerecke (2009).

Figures

Figures 8–9. Lebertia (Lebertia) cylinderia Wang & Guo, sp. nov., male. 8. Ventral view. 9. Dorsal view. Scale bars=200 µm.

Figures 10–15. Lebertia (Lebertia) cylinderia Wang & Guo, sp. nov., male. 10. Palp. 11. Gnathosoma. 12. Dorsal integument structure. 13. Genital field. 14. I-L-3–6. 15. IV-L-3–6. Scale bars: 10, 14–15=100 µm; 11–12=50µm; 13=200µm.