Torrenticola trongsaensis, PešićK & K & K, 2022

PešićK, Vladimir, K, Harry Smit & K, Mer Man Gurung, 2022, Torrenticolid water mites of Bhutan. Genera Torrenticola Piersig, 1896 and Neoatractides Lundblad, 1941 (Acari: Hydrachnidia: Torrenticolidae), Acarologia 1941 (3), pp. 821-860 : 842-843

Torrenticola trongsaensis sp. nov.

Zoobank: 67C92662-2D1B-4678-8E87-E6C0AFFA9F29

Figures 15, 16, 19H–J

Material examined — Holotype ♂, dissected and slide mounted, Bhutan, MG15 Khabab

Chhu, 27.48492°N, 90.33490°E, 2500 m asl, 14.v.2021. Paratypes: 1♂, 4♀, same data as holotype ; 1♀, MG 14 Chuserbu stream, 27.50246°N, 90.31782°E, 2666 m asl, 13.v.2021,

dissected and slide mounted; 1♀, MG 12 Nikka Chhu, 27.52601°N, 90.29947°E, 2609 m asl,

10.v.2021.

Diagnosis — Idiosoma large in size,> 1000 µm in both sexes; Cx-I relatively short,

anteriorly broad; gnathosomal rostrum short, less than width of gnathosoma; in both sexes suture lines of Cx-IV extending posteriorly beyond posterior margin of genital field; ejaculatory complex with well-developed anterior keel and proximal arms.

Description — General features – Idiosoma roundish; dorsal shield without a colour pattern (as photographed in Figures 19H–I); area of primary sclerotization of the dorsal plate with four dorsoglandularia; frontal platelets broad, frontal platelets broad, relatively short; Cx-I relatively short, anteriorly broad ( Figure 15C); gnathosomal bay U-shaped, proximally rounded;

Cxgl-4 subapical; medial suture line of Cx-II+III relatively short; suture lines of Cx-IV in both sexes distinctly extending posteriorly beyond posterior margin of genital field, laterally curved;

excretory pore and Vgl-2 away from the line of primary sclerotization, excretory pore on the level of Vgl-2; gnathosomal rostrum short, less than depth of gnathosoma ( Figure 16E); P-2

ventral margin nearly straight, P-2 and P-3 ventrodistal protrusions bluntly pointed, P-4 with a ventral tubercle bearing one long and three shorter setae ( Figures 15D, E) Male – Genital field elongated, subrectangular; ejaculatory complex conventional in shape ( Figure 19J). Female –

Genital field large and pentagonal in shape.

Measurements. Male (holotype) – Idiosoma (ventral view: Figure 15C) L 1065, W 853;

dorsal shield ( Figure 15B) L 909, W 738, L/W ratio 1.23; dorsal plate L 825; shoulder plate L

288–294, W 125–131, L/W ratio 2.2–2.3; frontal plate L 194, W 113–116, L/W ratio 1.68–1.72;

shoulder/frontal plate L 1.48–1.52. Gnathosomal bay L 206, Cx-I total L 397, Cx-I mL 191,

Cx-II+III mL 96; ratio Cx-I L/Cx-II+III mL 4.1; Cx-I mL/Cx-II+III mL 2.0. Genital field L/W

234/162, ratio 1.45; distance genital field-excretory pore 200, genital field-caudal idiosoma margin 313. Gnathosoma vL 334, chelicera L 384; palp total L 360, dL/H, dL/H ratio: P-1,

38/39, 0.96; P-2, 116/64, 1.81; P-3, 69/56, 1.22; P-4, 114/34, 3.32; P-5, 23/14, 1.7; L ratio

P-2/P-4 1.01. dL of I-L-2–6: 94, 109, 134, 153, 144; I-L-6 H 48; dL/H I-L-6 ratio 3.0.

Female (paratype from Chuserbu stream, n = 1) – Idiosoma (ventral view: Figure 16B) L

1108, W 906; dorsal shield ( Figure 16A) L 947, W 768, L/W ratio 1.23; dorsal plate L 869;

shoulder plate L 294–300, W 134–138, L/W ratio 2.17–2.2; frontal plate L 194, W 119, L/W

ratio 1.63; shoulder/frontal plate L 1.52–1.55. Gnathosomal bay L 206, Cx-I total L 397, Cx-I

mL 191, Cx-II+III mL 40; ratio Cx-I L/Cx-II+III mL 9.9; Cx-I mL/Cx-II+III mL 4.8. Genital field L/W 247/209, ratio 1.18; distance genital field-excretory pore 250, genital field-caudal idiosoma margin 397. Gnathosoma vL 353, chelicera L 366; palp total L 366, dL/H, dL/H ratio:

P-1, 38/40, 0.96; P-2, 118/61, 1.94; P-3, 72/58, 1.25; P-4, 117/36, 3.37; P-5, 21/14, 1.5; L ratio

P-2/P-4 1.0.

Etymology — The species is named after the district Trongsa from where the new species was collected.

Discussion — In regard to the presence of an anteriorly broad and short Cx-I, an elongated genital field in the male (L/W ratio about 1.4), and a deep gnathosoma, with a short rostrum,

the new species resembles T. retractipora ( Lundblad, 1941) and T. siamis Pešić & Smit,

2009. The latter two species can be separated from T. trongsaensis sp. nov. by Cx-IV not extended posterior of the genital field, and a comparatively shorter and stouter gnathosomal rostrum. Torrenticola retractipora , known from a single male specimen collected in a stream at Kambaiti pass in Myanmar differs by the characteristic shape of the ejaculatory complex

(similar to T. bhutana as illustrated in Figure 11G: proximal and distal arms short, proximal chamber large, proximal horns reduced, see Lundblad 1969, Figure 27f). Torrenticola siamis ,

a species originally described from Thailand, has a more elongated dorsal shield (L/W ratio 1.4

in ♂ holotype, data taken from Pešić and Smit 2009).