Torrenticola siamis Pešić & Smit, 2009

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 : 105-107

Torrenticola siamis Pešić & Smit, 2009

( Figs. 3–5 )

Material examined. Doupengshan, Guizhou Province, China (26°22′18′′N, 107°21′53′′E, 1038 m a.s.l.), stream, collected by Xinyao Gu, 2. X.2016, 1/0/1, No. GZ-TO-20161009–GZ-TO-20161010.

Description. Male (n = 1): Idiosoma roundish, L/W ratio 1.3 ( Fig. 3A ). Dorsal plate (4+1), frontal platelets nearly trapezoid, L/W ratio 1.9, shoulder platelets like an irregular rectangle, L/W ratio 2.0 ( Fig. 3B ). Infracapitular bay deep and broad, U-shaped; only the tips of Cx-I and Cx-II exceeding the anterior margin of idiosoma; Gf rectangular, L/W ratio 1.6, genital flaps with 14 pairs of setae at the margins; E 4 at the same level as the 4 th pair of acetabula; Ap slightly away from the line of primary sclerotization, on the same line with V 2 and posterior to V 1 ( Fig. 3A ). Infracapitulum acute triangle-like in the lateral view ( Fig. 3C ). P-1 short, with a dorsal seta; P-2 with three dorsal setae and a ventral seta on the ventrodistal protrusion; P-3 with two short and a long setae dorsally, and a seta on the ventrodistal protrusion; P-4 with three dorsal setae, a long and two short setae on two ventral protrusions; P-5 with a long dorsal and a long ventral setae ( Fig. 3E ).

Measurements. Idiosoma L 663, W 529. Dorsal shield L 597, W 483, dorsal plate L 530, frontal platelets L 160, W 83, shoulder platelets L 187, W 83. Infracapitular bay depth 137; Cx-1 L 249, mL 113, Cx-II +III mL 73; Gf L 188, W 116, distance between Gf and Ap 213. Gnathosoma vL 208, dL 150, chelicera bs L 177, claw L 60. Ejaculatory complex ( Fig. 3D ), L 209, aL 163. L of palp: P-1, 26; P-2, 67; P-3, 43; P-4, 70; P-5, 24. L of leg segments: I-L-1–6: 42, 97, 98, 120, 127, 116; II-L-1–6: 47, 100, 90, 116, 135, 132; III-L-1–6: 60, 75, 105, 127, 142, 148; IV-L-1–6: 95, 121, 119, 176, 183, 165.

Female. Not collected.

Deutonymph (n = 1): Body features same as the male except: frontal platelets L/W ratio 2.0, shoulder platelets L/W ratio 2.6 ( Fig. 5A ). Cx-II +III mL shorter than male; E 4 at the same level as the 5 th pair of acetabula; Gf pentagonal, L/W ratio 1.2, genital flaps with 20 setae at the margins ( Fig. 5B ).

Measurements. Dorsal shield L 660, W 547, dorsal plate L 591, frontal platelets L 183, W 92, shoulder platelets L 214, W 83. Infracapitular bay L 175; Cx-1 L 303, mL 127, Cx-II +III mL 40; Gf L 225, W 187. Gnathosoma vL 253, dL 176, chelicera bs L 227, claw L 175. L of palp: P-1, 33; P-2, 85; P-3, 54; P-4, 79; P-5, 30. L of leg segments: I-L-1–6: 72, 114, 111, 146, 148, 138; II-L-1–6: 57, 115, 99, 142, 152, 140; III-L-1–6: 42, 123, 97, 147, 178, 163; IV-L-1–6: 130, 163, 149, 210, 209, 202.

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

Remarks. Due to the characteristic shape of infracapitulum, gnathosoma with a short rostrum; Cx-II+III mL short; Gf rectangular; only the tips of Cx-I and Cx-II exceeding to the anterior margin of idiosoma, the specimens from China show a general conformity with that from Thailand ( Pešić & Smit 2009a). The species is firstly recorded for Chinese fauna.

The two populations are slightly different: (1) the shape of the ejaculatory complex: spindly flask in the Chinese population, but round-bottom flask in the Thai population; (2) the lateral view of infracapitulum: regular trianglelike in the Chinese population, while acute triangle-like in Thai population.

Distribution. China (Doupengshan); Thailand ( Pešić & Smit 2009a).

Figures

FIGURE 3. Torrenticola siamis Pešić & Smit, 2009, male: A = ventral view; B = dorsal view; C = infracapitulum and chelicera; D = ejaculatory complex; E = palp. Scale bars = 100 μm.

FIGURE 4. Torrenticola siamis Pešić & Smit, 2009, male: A = leg-I; B = leg-II; C = leg-III; D = leg-IV. Scale bars = 100 μm.

FIGURE 5. Torrenticola siamis Pešić & Smit, 2009, female:A = dorsal view; B = ventral view; C = palp; D = leg-I; E = leg-II; F = leg-III; G = leg-IV; H = infracapitulum and chelicera. Scale bars = 100 μm.