Torrenticola episce, Pešić, Vladimir, Chatterjee, Tapas, Das, Mrinal Kumar & Bordoloi, Sabitry, 2013

Pešić, Vladimir, Chatterjee, Tapas, Das, Mrinal Kumar & Bordoloi, Sabitry, 2013, A new species of water mite (Acari, Hydrachnidia) from Assam, India, found in the gut contents of the fish Botia dario (Botiidae), Zootaxa 3746 (3), pp. 454-462 : 455-458

Torrenticola episce sp. nov.

( Figs. 2A–E , 3A–C )

Type material. Holotype male, dissected and slide mounted, India, Assam State, Jorhat district, Majuli Island, Kakarikata beel, in the gut content of Botia dario (Hamilton, 1822) . Paratypes: three females, same data as holotype, two of them dissected and slide mounted.

Diagnosis. Shoulder platelets fused to dorsal plate, but suture line visible; the angle of dorsal plate between frontal plates pointed; area of primary sclerotization of the dorsal plate with two dorsoglandularia; Cxgl–4 posterior to Cxgl–2; excretory pore and Vgl–2 clearly posterior to the line of primary sclerotization; excretory pore slightly anterior to Vgl–2; suture of Cx-IV curved. Gnathosoma ventral margin curved, rostrum well developed; ventral margins of P-2, -3 and -4 with fine, indistinct serration; P-2 longer than P-4 (dL P-2/P-4 ratio 1.1–1.2); P-4 with well developed ventral tubercles, with one longer, and three shorter hairs. Male: median suture line of Cx- II+III relatively short (81 Μm, L ratio Cx-I/Cx-II+III 2.8), genital field rectangular in shape.

Description. Male (holotype): Idiosoma (ventral view: Fig. 2B ) L 653, W 513; dorsal shield ( Fig. 2A ) L 551, W 434, L/W ratio 1.27; dorsal plate 529; frontal platelets L 106–113, W 41–42, L/W ratio 2.5–2.7; gnathosomal bay L 117; Cx-I total L 228, Cx-I mL 110, Cx-II+III mL 81; ratio Cx-I L/Cx- II+III mL 2.8; Cx-I mL/Cx-II+III mL 1.35; genital field L/W 131/103, L/W ratio 1.27; ejaculatory complex normal in shape (proximal and distal arms and proximal chamber well developed), L 166; distance genital field–excretory pore 134, genital field–caudal idiosoma margin 213; gnathosoma ( Fıg. 2C ) vL 275; chelicera total L 316; palp ( Figs. 2D–E ): total L 289, dL/H, dL/H ratio: P-1 34/35, 0.96; P-2 94/46, 2.0; P-3 57/42, 1.35; P- 4 85/28, 3.1; P- 5 19/13, 1.4; dL P-2/P-4 ratio 1.1. dL of I-L-2-6: 60, 78, 91, 97, 91.

Female (paratypes, n = 2): Idiosoma (ventral view: Fig. 3B ) L 806–850, W 663–687; dorsal shield ( Fig. 3A ) L 700–713, W 556, L/W ratio 1.26–1.28; dorsal plate 663–681; frontal platelets L 128–134, W 50–53, L/W ratio 2.5– 2.6; gnathosomal bay L 151–155; Cx-I total L 291–306, Cx-I mL 139–148, Cx-II+III mL 16–38; ratio Cx-I L/Cx- II+III mL 7.8–19.6; Cx-I mL/Cx-II+III mL 3.7–9.5; genital field L/W 164–166/136–137, L/W ratio 1.2; L; egg (n = 1) maximum diameter 178; distance genital field–excretory pore 173–206, genital field–caudal idiosoma margin 301–348; posterior suture line of Cx-IV; gnathosoma vL 348–356; chelicera total L 386–441; palp ( Fig. 3C ): total L 361–377, dL/H, dL/H ratio: P-1 43/45–46, 0.93–0.96; P-2 120–128/59–65, 2.0–2.1; P-3 71–73/54, 1.3–1.35; P-4 105–109/31, 3.4–3.5; P- 5 22–24/16 –17, 1.3–1.5; dL P-2/P-4 ratio 1.15–1.17. dL of I-L-2–6: 71, 86, 112, 120, 111.

Etymology. The species is named after being collected in a fish.

Discussion. The new species belong to the Torrenticola ungeri – species complex, characterized by a dorsal shield with shoulder platelets fused or partially fused with dorsal plate and Cxgl–4 posterior to Cxgl–2. This complex include a group of six Asian species: Torrenticola occulta Lundblad, 1971 (Java; Lundblad 1971), T. ussuriensis (Sokolow, 1940) (Far East of Russia, Japan, Korea; Pešić et al. 2011, 2013), T. microdentifera Cook, 1967 ( India: Maharashtra; Cook 1967), T. taiwanicus Pešić, Semenchenko, Chatterjee, Yam & Chan, 2011 ( Taiwan; Pešić et al. 2011), T. ungeri (Szalay, 1927) (Western Palaearctic; Di Sabatino et al. 2010) and Torrenticola sp. sensu Pešić & Smit, 2009 ( Thailand; Pešić and Smit 2009a). The new species can be distinguished from all the abovementioned species by having, in addition to fine serration on ventral margin of P-3 and P-4, a fine indistinct serration on the ventral margin of P-2. At least three of the abovementioned species, T. ungeri , T. microdentifera and T. sp. sensu Pešić & Smit, bears fine ventral serration on P-4. Torrenticola ungeri differs in having a group of long setae and bristle on the apex of Cx-I, and the excretory pore lying posterior to Vgl–2. Torrenticola microdentifera differs in lacking well developed tubercles of P-4, the shape of dorsal shield with the angle of dorsal plate between the frontal plates slightly pointed, the suture line of Cx-IV posterior to the genital field more extended, and the excretory pore on the same level as Vgl-2 and shifted more to the line of primary sclerotization (see: Cook 1967). Due to the well developed tubercles on P-4, the new species from Assam resemble specimens of the Torrenticola ungeri -complex from Thailand (see: Pešić and Smit 2009a). The specimens from Thailand were not assigned to any of the known species as the juveniles of the both sexes and one semi-adult male has fine serration on ventral margins of P-3 and P-4, but the single adult female lacks ventral serration on P-3 and P-4 (Pešić and Smit 2009a). We have not excluded the possibility that in case of Thailand’s specimens we are dealing with two species collected at the same site. As stated by Pešić and Smit (2009a) additional material is required to clarify the status of these specimens.

Distribution. Assam ( India).

Figures

FIGURE 2 A – E. Torrenticola episce sp. nov., holotype male: A = dorsal shield; B = ventral shield; C = gnathosoma; D = palp, medial view; E = palp, lateral view. Scale bars = 100 Μm.

FIGURE 3 A – C. Torrenticola episce sp. nov., paratype female: A = dorsal shield; B = ventral shield; C = palp, medial view. Scale bars = 100 Μm.