Atractides (Atractides) bhutanicus, PešićK & SmitK & GurungK, 2023

PešićK, Vladimir, SmitK, Harry & GurungK, Mer Man, 2023, Five new species of water mite genus Atractides Koch, 1837 from Bhutan with new records (Acari: Hydrachnidia: Hygrobatidae), Acarologia 63 (1), pp. 148-168 : 158-161

Atractides (Atractides) bhutanicus sp. nov.

Zoobank: F09D45C0-7937-441A-AA3D-CA3D46DE9537

Figures 7-8

Type material — Holotype ♂, dissected and slide mounted ( NBC), Bhutan, MG16 Chendebji Chhu , 27.47692°N, 90.35265°E, 2483 m asl, 8 Nov. 2021 . Paratypes: 2♀, same site and data as the holotype, 1♀ dissected and slide mounted ( NBC).

Other material — Bhutan, MG 13 Rukhubji Chhu, 27.51174°N, 90.29711°E, 2587 m asl,

5 Nov. 2021, 1♂, 6♀.

Diagnosis — Integument finely striated, muscle insertions unsclerotized; anterior margin of male genital field slightly concave, but without an indentation; Vgl-1 separate from Vgl-2; P-2 with a distoventral projection, ventral margin of P-4 projecting.

Description — General features – Integument striated, muscle insertions unsclerotized; mediocaudal margin Cx-I convex, apodemes of Cx-II in an acute angle with the median line. Genital field with large Ac in a triangular arrangement. Excretory pore smooth; Vgl-1 not fused to Vgl-2. Palp with sexual dimorphism, P-4 sword seta slender, between ventral setae, nearer to distoventral seta. I-L-5 with seta S-1 slender and bluntly pointed, S-2 shorter and pointed, proximally enlarged; I-L-6 slender, curved, basally slightly thickened ( Figure 7C).

Male – Genital plate anterior margin slightly concave, posterior margin deeply indented ( Figure 7A); P-2 with a finger-like distoventral protrusion, P-3 ventral margin concave, P-4 thickened, maximum height at level of proximoventral hair ( Figure 7B).

Female – P-2 ventral margin convex distally ( Figure 8B).

Measurements — Male – Idiosoma L 558, W 428; maximum diameter Dgl-4 27. Coxal shield L 344; Cx-III W 375; Cx-I+II mL 131, Cx-I+II lL 250. Genital field L/W 117/136, ratio 0.86, L Ac-1-3: 52-58, 52, 44-52. Ejaculatory complex L 105.

Palp – Total L 324; dL/H, dL/H ratio: P-1, 33/31, 1.08; P-2, 72/63, 1.15; P-3, 77/48, 1.6;

P-4, 106/44, 2.41; P-5, 36/17, 2.16; L ratio P-2/P-4, 0.68. Gnathosoma vL 150, chelicera total

L 217.

Legs – I-L-5 dL 209, vL 137, dL/vL ratio 1.53, maximum H 63, dL/maximum H 3.31, S-1

L 102, L/W ratio 10.8, S-2 L 80, L/W ratio 5.65, distance S-1-2, 27, dL ratio S-1/2, 1.28; I-L-6

dL 140, central H 22, dL/central H ratio 6.39; L I-L-5/6 ratio 1.5.

Female – Idiosoma L 713, W 550; maximum diameter Dgl-4, 22. Coxal shield L 378; Cx-III W 447; Cx-I+II mL 112, Cx-I+II lL 253. Genital field L/W 152/167, genital plates L 125-128, pregenital sclerite 49, gonopore L 118, L Ac-1-3: 55-56, 53-55, 46-47.

Palp – Total L 412; dL/H, dL/H ratio: P-1, 37/34, 1.07; P-2, 84/57, 1.48; P-3, 116/45, 2.55; P-4, 134/34, 3.91; P-5, 41/16, 2.6; L ratio P-2/P-4, 0.63. Gnathosoma vL 141, chelicera total L 247.

Legs – I-L-5 dL 281, vL 180, dL/vL ratio 1.57, maximum H 66, dL/maximum H 4.25, S-1 L 139, L/W ratio 11.1, S-2 L 106, L/W ratio 6.2, distance S-1-2, 44, dL ratio S-1/2, 1.31; I-L-6 dL 205, central H 20, dL/central H ratio 10.1; L I-L-5/6 ratio 1.37.

Etymology — The new species is named after the country where the new species was collected.

Discussion — In regard to the striated integument and the shape of the palp in the male (P-2 with distoventral projection, ventral margin of P-4 projecting), the new species resembles species of the A. nodipalpis complex (see above, under discussion of A. conflatus sp. nov.). However, males in the latter species complex differ from the new species by the shape of genital field with anterior and posterior indentations (anterior margin slightly concave, but without medial identation in A. bhutanicus sp. nov.). As Gerecke (2003) pointed out, the development of a ventrodistal protrusion of P- 2 in males probably has evolved independently in various, not closely related species groups.

Distribution — Bhutan ; know from high-order streams at an elevation above 2400 m ( Figure 12B).