Torrenticola tenuichelicera Gu & Guo, 2018

Gu, Xinyao, Jin, Daochao, Yi, Tianci & Guo, Jianjun, 2019, Contributions to the knowledge of Torrenticolid water mites (Acari: Hydrachnidia) in Doupengshan, China, Zootaxa 4695 (2), pp. 101-121 : 102-105

Torrenticola tenuichelicera Gu & Guo, 2018

( Figs. 1–2 )

Material examined. Doupengshan, Guizhou Province, China (26°22’4”N, 107°21’55”E, 1407 m a.s.l.), stream, collected by Xinyao Gu, 2. X.2016, 1/2/0, No. GZ-TO-20161006–GZ-TO-20161008.

Description. Male (n = 1): Idiosoma elliptical, L/W ratio 1.4 ( Fig. 1A ). Dorsal plate (4+1), frontal platelets L/W ratio 2.4, shoulder platelets L/W ratio 2.6; E 4 on the same line with the 3 rd pair of acetabula; genital field L/W ratio 1.3 ( Fig. 1B ). P-2 long, with five dorsal setae and its ventral margin convex, with a short ventrodistal prolongation, which is blunt, slightly curved towards the distal, and with a seta at the base; P-3 with two setae on dorsum and a ventrodistal cone-shaped prolongation; P-4 with two developed ventral prolongations ( Fig. 1C ).

Measurements. Idiosoma L 790, W 565. Dorsal shield L 630, W 513, dorsal plate L 586, frontal platelets L 162, W 68, shoulder platelets L 196, W 74. Infracapitular bay L 156; Cx-I L 298, mL 141, Cx-II +III mL 106; Gf L 187, W 140, distance between Gf and Ap 108. Gnathosoma vL 355, dL 260, chelicera bs L 340, claw L 56. Ejaculatory complex ( Fig. 1D ), L 229, aL 153. L of palp: P-1, 38; P-2, 102; P-3, 60; P-4, 79; P-5, 17. L of leg segments: I-L-1–6: 35, 89, 72, 92, 111, 101; II-L-1–6: 45, 88, 70, 93, 114, 110; III-L-1–6: 49, 100, 87, 109, 131, 106; IV-L-1–6: 106, 105, 122, 145, 152, 135.

Female (n = 2): Idiosoma elliptical, L/W ratio 1.4 (1.3); Dorsal plate (4+1), frontal platelets trapezoid, L/W ratio 2.2 (2.3), shoulder platelets rectangular, laterally rounded, L/W ratio 2.7 (2.4) ( Fig. 2B ). Infracapitular bay deep and broad, V-shaped; E 4 on the same line with the 5 th pair of acetabula; genital field nearly pentagonal, L/W ratio 1.1 (1.1); Ap posterior to V 3, anterior to V 2, and on the same line with V 1 ( Fig. 2A ). P-1 with a dorsal seta; P-2 long, with six dorsal setae and one ventrodistal blunted protrusion, which slightly curved towards distally and with one seta at the base; P-3 with two dorsal setae and one ventrodistal cone-shaped protrusion; P-4 with one dorsal seta, two ventral protrusions, ending in two blunt tips separated by a concavity, and with three setae on them ( Fig. 2G ). Gnathosoma elongated, rostrum very long and slender, chelicera long and straight ( Fig. 2H ).

Measurements. Idiosoma L 780 (843), W 557 (632). Dorsal shield L 603 (683), W 484 (527), dorsal plate L 553 (618), frontal platelets L 151 (170), W 68 (73), shoulder platelets L 199 (196), W 73 (83). Infracapitular bay depth 154 (177); Cx-1 L 292 (340), mL 138 (163), Cx-II +III mL 67 (80); Gf L 183 (187), W 170 (175), distance between Gf and Ap 145 (147). Gnathosoma vL 362 (386), dL 251 (288), chelicera bs L 399 (372), claw L 53 (59). L of palp segments: P-1, 40 (36); P-2, 108 (118); P-3, 61 (68); P-4, 80 (84); P-5, 15 (19). L of leg segments: I-L-1–6: - (50), 88 (87), 72 (87), 88 (97), 104 (109), 100 (93); II-L-1–6: 52 (46), 90 (70), 71 (73), 98 (101), 107 (113), 103 (103); III-L-1–6: 45, 103, 77 (83), 119 (100), 133 (143), 119 (123); IV-L-1–6: 115 (100), 103 (107), 130 (119), 148 (147), 157 (160), 136 (154).

Habitat. Stream about 20 centimeters depth, 5 meters wide, located between the mountains and a farmland; with mayflies and leeches as associated fauna.

Remarks. This species shows a general conformity with specimens of T. tenuichelicera , characterized by gnathosoma elongated, chelicera long and straight; P-2 ventral margin convex, ventrodistal protrusion bluntly pointed, slightly curved towards distally, and with a seta at the base; P-3 with two dorsal setae, and a ventrodistal coneshaped protrusion; P-4 with two developed ventral protrusions, with three setae. T. tenuichelicera was previously known from Fodingshan (Foding Mountain), China, and only described in the male sex. In this paper, the description of the female is given for the first time.

The two populations are different slightly: (1) E 4 on the same line with the 3 rd pair of acetabula in male, and the 5 th pair in female in Doupengshan population, while on the 4 th line in male in Fodingshan population; (2) P-2 with five dorsal setae in male and six dorsal setae in female in Doupengshan population, but with eight dorsal setae in male in Fodingshan population.

Distribution. China (Doupengshan, Fodingshan) ( Gu, Jin, Yi & Guo 2018).

Figures

FIGURE 1. Torrenticola tenuichelicera Gu & Guo, 2018, male: A = ventral view; B = dorsal view; C = palp; D = ejaculatory complex; E = infracapitulum and chelicera; F = leg-I; G = leg-II; H = leg-III; I = leg-IV. Scale bars = 100 μm.

FIGURE 2. Torrenticola tenuichelicera Gu & Guo, 2018, female:A = ventral view; B = dorsal view; C = I-L-2–6; D = leg-II; E = leg-III; F = leg-IV; G = palp; H = infracapitulum and chelicera. Scale bars = 100 μm.