Atractides (Tympanomegapus) himalayicus, 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 : 164

Atractides (Tympanomegapus) himalayicus sp. nov.

Zoobank: 50BE8FE5-D47C-4F2B-A7C8-F7E639DBEF46

Figure 11

Type material — Holotype ♀, dissected and slide mounted ( NBC), Bhutan, MG3 Bipgang Chhu , 27.15729°N, 90.66721°E, 596 m asl, 25 Oct. 2021 . Paratypes: 2♀, same site and data as the holotype ( NBC).

Diagnosis — Female (male unknown) – Muscle insertions unsclerotized; excretory pore sclerotized; Vgl-1 not fused to Vgl-2; P-4 sword seta thicker, not hair-like; P-5 with lateral ′cheeks’; claws without dorsal clawlets.

Description — Female – Integument striated, muscle insertions unsclerotized. Glandularia enlarged (Dgl-4, 41). Mediocaudal margin of Cx-I+II curved, apodemes of Cx-II forming an acute angle, lateral and posterior margins of Cx-III+IV with extended secondary sclerotization, distinctly projecting posteriorly at lateral edges. Acetabula in triangular arrangement, pregenital sclerite strong and curved, genital plates weakly concave medially ( Figure 11C). Excretory pore sclerotized; Vgl-1 not fused to Vgl-2. Ventral margin of P-2 straight, P-3 ventral margin weakly concave, P-4 with straight ventral and equally curved dorsal margin, sword seta of

P-4 pointed, thicker, but not hair-like, inserted distally from distoventral hair, P-5 with lateral ′cheeks’. ( Figure 11F). I-L-5/-6 with S-1/-2 bluntly pointed; I-L-6 with a regular row of ventral setae, claws strong, without dorsal clawlets ( Figure 11G).

Measurements — Idiosoma L 838, W 600; maximum diameter Dgl-4, 41. Coxal shield L 422; Cx-III W 472; Cx-I+II mL 127, Cx-I+II lL 256. Genital field L/W 166/223, genital plates

L 134-139, pregenital sclerite W 92, gonopore L 128, L Ac-1-3: 59, 56-63, 58-59.

Palp – Total L 388; dL/H, dL/H ratio: P-1, 45/14, 3.21; P-2, 81/44, 1.85; P-3, 103/36, 2.83;

P-4, 124/31, 3.97; P-5, 35/16, 2.24; L ratio P-2/P-4, 0.65. Gnathosoma vL 205, chelicera total

L 336.

Legs – I-L-5 dL 214, vL 160, dL/vL ratio 1.34, maximum H 47, dL/maximum H 4.59, S-1

L 73, L/W ratio 9.3, S-2 L 73, L/W ratio 7.3, distance S-1-2, 10, dL ratio S-1/2, 1.0; I-L-6 dL

147, central H 27, dL/central H ratio 5.37; L I-L-5/6 ratio 1.46.

Male — Unknown.

Etymology — The species is named after the Himalayan mountain range from where the new species was collected.

Discussion — Due to the presence of a thicker, not hair-like sword seta on P-4, P-5

with lateral “cheeks″, unfused Vgl-1 and -2, and leg claws without dorsal clawlet, the new species resembles Atractides projectus Yi & Jin, 2010 and A. anhuiensis Yi & Jin, 2010 , both described from Anhui Province in China ( Yi et al. 2010). The latter species from China can be distinguished easily from the new species by the presence of an unsclerotized excretory pore. Moreover, A. projectus differs in the shape of the genital field with pregenital sclerite shorter than postegenital sclerite and Cx-III-IV possessing anterior, median and posterior apodemes ( Yi et al. 2010).

Atractides jukii Cook, 1967 , a species originally described from Maharashtra State ( Cook, 1967) and later on reported from the Himalayan region from Uttarakhand state differs from the new species from Bhutan in the presence of a hair-like sword seta on P-4 ( Pešić et al.

2019). Atractides brevis Yi & Jin, 2010 , another Tympanomegapus species reported from the Himalayas, known from Guizhou province in China, differs in the absence of lateral ′cheeks’ on P-5, fused Vgl-1+2, and unsclerotized excretory pore ( Yi et al. 2010).

Distribution — Bhutan ; known only from the type locality ( Figure 12A).