Torrenticola (Megapalpis) anophthalma, Pešić, Vladimir & Gerecke, Reinhard, 2014

Pešić, Vladimir & Gerecke, Reinhard, 2014, Water mites from caves of the Ha Giang province, northern Vietnam (Acari: Hydrachnidia), Zootaxa 3774 (4), pp. 367-380 : 368-370

Torrenticola (Megapalpis) anophthalma sp. nov.

( Figs. 1A –F, 2A–D, 3A–C, 9C)

Type series. Holotype female, dissected and slide mounted, Vietnam CO4, QBTS 0 3, Ha Giang, Quan Ba, Tam Son, transition cave, gours of dripping water – internal canyon, 23º02'44.7'' N, 104º59'23.9'' E, 980 m asl., 29.i.2010, Tomasin. Paratypes: two males (damaged; male 1: legs and genital flaps lacking; male 2: palps, legs and one genital flap lacking) and one deutonymph, same data as holotype, dissected and slide mounted.

Diagnosis. Idiosoma roundish, ocular pigment absent; Cxgl–4 hardly visible, subapical; suture line of Cx-IV faint; excretory pore included into primary sclerotization; P-2 long (L ratio P-2/P-4 1.4–1.5), ventral margin strongly concave, with a distally-directed, long, tapering ventrodistal extension bearing a short seta, P-3 medially with a protuberance, P-4 slender, medially with three protuberances (two of them close together in proximal part, one smaller and placed more distally); gnathosomal rostrum long, slightly bent dorsally; cheliceral claw fine and needle-like, ratio basal segment/claw 3.0.

Description. Both sexes: After fixation, without remarkable colour patches. Idiosoma compact, oval in shape, with short postgenital area. Frontal and shoulder plates relatively large, separate. Gnathosomal bay of a proximally rounded V-shape. Distal edge of Cx-I flanking gnathosomal bay smooth, lacking denticles or knob-shaped protrusions. Genital field relatively long, elliptical. Excretory pore located on the line of flanking glandularia. P-2 with one dorsodistal seta; P-3 with two setae (one on proximal dorsal margin, one dorsodistally – both lost in female, but sockets visible) and a triangular medioventral protuberance in centre of segment; P-4 equally tapering from base to tip, with one dorsal seta, a distomedial peg-like seta (short and pointed) and four ventral setae (from base to tip, three on pointed sockets, one short, one long, one very short, the fourth long and inflated, on the straight surface).

Female (holotype)—Idiosoma (ventral view: Fig. 1B ) L 450, W 309; dorsal shield ( Figs. 1A , 9C ) L 353, W 272, L/W ratio 1.3; dorsal plate L 313; shoulder plate L 141–144, W 61, L/W ratio 2.3; frontal plate L 75–81, W 51–53, L/W ratio 1.47–1.53; shoulder/frontal plate L ratio 1.7–1.9. Gnathosomal bay L 90, Cx-I total L 191, Cx-I mL 100, Cx-II+III mL 56; ratio Cx-I L/Cx-II+III mL 1.9; Cx-I mL/Cx-II+III mL 1.8. Genital field with subparallel lateral margins, L/W 133/100, ratio 1.33; distance genital field-excretory pore 43, genital field-caudal idiosoma margin 85. Gnathosoma ( Fig. 1C ) vL 255; chelicera total L 263, basal segment L 205, claw L 69, L basal segment/ claw ratio 3.0; palp ( Figs. 1D–E ) total L 318–326, dL: P-1, 41–43; P-2, 123–125; P-3, 56–59; P-4, 85–86; P-5, 13; P-2/P-4 ratio 1.45. Leg: dL of I-L-4–6 ( Fig. 1 F): 49, 58, 66; I-L-6 H 28, I-L-6 L/H ratio 2.4.

Male (paratypes, n = 2)—Idiosoma (ventral view: Fig. 2A ) L 430–441, W 284–297; dorsal shield (Figs.) L 320, W 266, L/W ratio 1.2; dorsal plate L 288; shoulder plate L 134–141, W 61–66, L/W ratio 2.0–2.3; frontal plate L 78, W 47–50, L/W ratio 1.56–1.66; shoulder/frontal plate L ratio 1.7–1.8. Gnathosomal bay L 80–88, Cx-I total L 194–197, Cx-I mL 107–113, Cx-II+III mL 66–79; ratio Cx-I L/Cx-II+III mL 2.8–3.0; Cx-I mL/Cx-II+III mL 1.6. Genital field L/W 106/78, ratio 1.36; distance genital field-excretory pore 47, genital field-caudal idiosoma margin 70. Gnathosoma ( Fig. 2D ) vL 240; palp ( Figs. 2B–C ) total L 292–293, dL: P-1, 35; P-2, 111–112; P-3, 54; P-4, 80; P-5, 12; P-2/P-4 ratio 1.4.

Deutonymph (paratype)—Idiosoma (ventral view: Fig. 3A ) L 392, W 278; dorsal shield ( Fig. 3B ) L/W 206/ 175, ratio 1.18. Coxal field: L 258, W 228, gnathosomal bay L 66. Provisional genital field with two pairs of acetabula, L/W 72/69, ratio 1.04. Palp ( Fig. 3C ): total L 228, dL: P-1, 28; P-2, 85; P-3, 41; P-4, 63; P-5, 11; P-2/P- 4 ratio 1.35. Legs: dL of I-L-2–6: 30, 29, 34, 43, 51.

Etymology. The name of the new species refers to the reduced eyes (anophthalmo s, gr.: without eyes).

Remarks. Following Di Sabatino et al. (2010), the subgenus Megapalpis Halbert, 1944 , in addition to Torrenticola s.s. the only subgenus, is characterized by the following features: (1) gnathosomal rostrum very long, bent dorsally; (2) chelicera long with slender stylet-like claw; (3) P-2 longer than P-3; (4) P-2 and P-3 lacking ventrodistal extensions. However, some species of the subgenus possess a weakly pronounced ventral projection on P-2 which is usually distanced from distal edge, but in Torrenticola (Megapalpis) khorassanula Pešić & Saboori, 2006 from Iran this ventral projection is in ventrodistal position ( Pešić et al. 2006, see there for further discussion). The new species is distinct in the long, tapering ventrodistal extension on P-2, the medial protuberances on P-3 and P-4, and the excretory pore incorporated into primary sclerotization of the ventral shield. Medial protuberances on P-4, combined with reduced ocular pigment are found also in some hyporheobiontic species of the subgenus Torrenticola (see Di Sabatino et al. 2010), but agreement in the above named character states (1)-(3) is strong argument for placing T. anophthalma in Megapalpis . The character state (4), “P-2 and P-3 lacking ventrodistal extensions” should be skipped from the diagnosis of that subgenus. The idiosoma shape of the new species, with relatively large anterodorsal plates and a shortened posteroventral area, strongly resembles the morphology of juvenile adults often observed in other torrenticolid species. The study of further material should clarify whether this character combination is a general consequence of juvenilazation in T. anophthalma (as it is often observed in subterranean species), or the specimens of the type series are just juvenile adults.

Distribution. Vietnam; only known from the locus typicus.

Figures

FIGURE 1 A – E. Torrenticola anophthalma sp. nov., female holotype: A = dorsal shield; B = ventral shield; C = gnathosoma and chelicera; D = palp, medial view; E = palp, lateral view; F = I – L- 4 – 6. Scale bars = 100 Μm.

FIGURE 9 A – E. A – C Photographs of dorsal shield. A – B Stygotorrenticola coniseta sp. nov., male: A = holotype; B = paratype. C Torrenticola anophthalma sp. nov., female. D – E Photographs of Africasia vietnamitica sp. nov., female: D = dorsal shield; E = ventral shield.

FIGURE 2 A – D. Torrenticola anophthalma sp. nov., male: A = idiosoma, ventral view; B = palp, lateral view (P- 1 missing); C = palp, medial view (P- 1 missing); D = gnathosoma. Scale bars = 100 Μm.

FIGURE 3 A – C. Torrenticola anophthalma sp. nov., deutonymph: A = idiosoma, ventral view, B = dorsal plate; C = palp, lateral view (P- 1 missing). Scale bars = 100 Μm.