Monatractides euterpe, Pešić, Vladimir & Smit, Harry, 2014

Pešić, Vladimir & Smit, Harry, 2014, Torrenticolid water mites (Acari: Hydrachnidia: Torrenticolidae) from Ghana, Zootaxa 3820 (1), pp. 1-80 : 42-44

Monatractides euterpe n. sp.

( Figs. 27A–H , 37C–D , 38C–D , 44C )

Type series. Holotype male, dissected and slide mounted, Ghana: Unnamed creek upstream Sagyimase, Atewa Hills, 6º 13.966 N, 0º 33.114 W, alt. 671 m asl., 28.ii.2013, Smit. Paratype: 0/2/0, same data as holotype, one of them dissected and slide mounted; 1/1/0, small rainforest stream upstream Sagyimase, Atewa Hills, 6º 13.964 N, 0º 33.116 W, alt. 654 m asl., 8.iii.2011, Smit, dissected and slide mounted.

Diagnosis. Idiosoma elongated-oval; frontal margin medially with large anterolaterally pointed apodemes; gnathosomal bay narrow U-shaped, proximally pointed; excretory pore well anterior to Vgl–2 and away from the line of primary sclerotization; ventral setae on P-4 slender and short, not reaching the tip of P-5. Male: medial margin of Cx-II/III moderately long; ejaculatory complex with small proximal chamber.

Description. General features —Idiosoma elongated-oval; shoulder platelets elongated (shoulder/frontal platelets L ratio 1.3–1.4); frontal margin medially with large anterolaterally pointed apodemes ( Fig. 27E ); Cxgl–4 located far distal, nearly at tips of Cx-I; gnathosomal bay narrow U-shaped, proximally pointed, three pairs of knob-like protrusions at the lateral margins of gnathosomal bay; suture line of Cx-IV distinct, originating from lateral edge of genital field and directed posterolaterally; excretory pore away from the line of primary sclerotization, Vgl–2 well posterior to excretory pore; gnathosoma compact, with long dorsal apodemes, rostrum truncated ( Fig. 27H ); palp ( Fig. 27D ): ventral and dorsal setae of P-2 and P-3 relatively strong and long, P-2 and P- 4 almost equal in length, distal margin of P-3 and P-4 medially and laterally with several pointed extensions; ventral setae on P-4 slender and short, not reaching the tip of P-5. Male: medial margin of Cx-II/III moderately long; genital field subrectangular, anteriorly enlarged and triangular, lateral margins straight to slightly convex, slightly tapering to caudal end; ejaculatory complex with small proximal chamber, carina anterior long ( Figs. 27G , 44C ). Female: genital field elongated trapezoid, anteriorly pointed, laterally straight, tapering towards posterior.

Measurements Male (holotype, in parentheses paratype, n = 1)—Idiosoma (ventral view: Figs. 27B , 38C ) L 708 (700), W 509 (481); dorsal shield ( Figs. 27A , 37C ) L 597 (598), W 447 (417), L/W ratio 1.34 (1.43); dorsal plate L 556 (544); shoulder platelets L 156 (150), W 63–64 (66), L/W ratio 2.4–2.5 (2.3); frontal platelets L 113–116 (112), W 66–70 (72), L/W ratio 1.6–1.8 (1.6); shoulder/frontal platelets L ratio 1.35–1.4 (1.34). Gnathosomal bay L 125 (130), Cx-I total L 256 (250), Cx-I mL 125 (120), Cx-II+III mL 76 (80); ratio Cx-I L/Cx- II+III mL 3.4 (3.1); Cx-I mL/Cx-II+III mL 1.6 (1.5). Genital field L/W 139 (134)/106 (109), ratio 1.31 (1.23); distance genital field-excretory pore 154 (128), genital field-caudal idiosoma margin 235 (234); ejaculatory complex L 179 (169). Gnathosoma vL 143 (147); chelicera total L 187 (186); palp total L 205 (205–206), dL/H, dL/H ratio: P-1, 26/25, 1.06 (25/23–24, 1.05); P-2, 57/40, 1.43 (57/37, 1.54); P-3, 37/33, 1.13 (38/31–32, 1.2); P-4, 57/24, 2.4 (57/23, 2.5); P-5, 28/12, 2.2 (28–29/14, 2.1); P-2/P-4 ratio 0.97 (0.99); dL of I-L-2–6: (80), (84), (100), (95), (100); I-L-6 H (38), dL/H I-L-6 ratio (2.65).

Female (paratypes, n = 2)—Idiosoma (ventral view: Figs. 27C , 38D ) L 775–809, W 531–544; dorsal shield ( Fig. 37D ) L 678–684, W 475–497, L/W ratio 1.38–1.43; dorsal plate L 613–628; shoulder platelets L 163–177, W 66–75, L/W ratio 2.35–2.48; frontal platelets L 119–123, W 76–83, L/W ratio 1.49–1.6; shoulder/frontal platelets L ratio 1.33–1.45. Gnathosomal bay L 141–150, Cx-I total L 272–280, Cx-I mL 129–131, Cx-II+III mL 62–75; ratio Cx-I L/Cx-II+III mL 3.73–4.4; Cx-I mL/Cx-II+III mL 1.7–2.1. Genital field L/W 169–172/145–151, ratio 1.14–1.16; egg maximum diameter (n = 1) 211; distance genital field-excretory pore 136–147, genital field-caudal idiosoma margin 266–281. Gnathosoma vL 162; chelicera total L 191–206; palp total L 217–226, dL/H, dL/H ratio: P-1, 24–29/24–25, 1.0–1.2; P-2, 60–63/41–44, 1.37–1.51; P-3, 41–43/37, 1.12–1.17; P-4, 59–64/25–26, 2.4–2.5; P-5, 29–30/15–17, 1.7–2.0; P-2/P-4 ratio 0.94–1.06; dL of I-L-2–6: 69–75, 89–85, 102–106, 100–102, 106–107; I-L-6 H 41–45, dL/H I-L-6 ratio 2.4–2.6.

Etymology. The species is named after Euterpe (Ancient Greek: Eὐτέρπη), one of nine Muses from Greek mythology, who was a patron of lyric poetry and song. The species name is a noun in apposition (in the nominative case).

Discussion. The new species seems to be most similar to Monatractides melpomene n. sp. (see below). Both species resemble Monatractides cf. ventriosus (see above) in the general shape of coxal field, but the latter species can be distinguished by a longer ventral seta on P-4, exceeding away from the distal edge, a larger proximal chamber of the male ejaculatory complex, and the excretory pore shifted far posterior to the line of primary sclerotization, and consequently, Vgl–2 less separated from the excretory pore. Monatractides melpomene n. sp. can be separated from M. euterpe n. sp. due to the less slender idiosoma, the characteristic colour pattern (see Figs. 37A–B ), ventral seta on P-2 comparatively slender than the seta on P-3, and in males, genital flaps with long and fine setae.

Habitat. sandy/bouldary streams, shaded by rain forest.

Distribution. Ghana.

Figures

FIGURE 27 A – H. Monatractides euterpe n. sp., unnamed creek upstream Sagyimase (A – B, D – E = male, C = female): A = dorsal shield; B – C = idiosoma, ventral view; D = palp, lateral view; E = frontal margin of idiosoma, dorsal view; F = I-L- 5 and - 6; G = ejaculatory complex; H = gnathosoma; Scale bars = 100 Μm.

FIGURE 37 A – I. Photographs of dorsal shield. A – B Monatractides melpomene n. sp., Amedzofe Falls: A = male holotype, B = female paratype. C – D M. euterpe n. sp., creek upstream Sagyimase: C = male holotype, D = female paratype. E – F M. polyhymnia n. sp., Kue River: E = male holotype, F = female paratype. G M. thalia n. sp., male holotype, Agumatsa River. H M. terpsichore n. sp., female holotype, Plunge pool. I M. urania n. sp., male paratype, Kintampo Falls.

FIGURE 38 A – I. Photographs of ventral shield. A – B Monatractides melpomene n. sp., Amedzofe Falls: A = male holotype, B = female paratype. C – D M. euterpe n. sp., creek upstream Sagyimase: C = male holotype, D = female paratype. E – F M. polyhymnia n. sp., Kue River: E = male holotype, F = female paratype. G M. thalia n. sp., male holotype, Agumatsa River. H M. terpsichore n. sp., female holotype, Plunge pool. I M. urania n. sp., male paratype, Kintampo Falls.

FIGURE 44 A – L. Photographs of ejaculatory complex: A Monatractides convexiscutata (K. Viets, 1958), male, Asukuma River. B M. melpomene n. sp., Amedzofe Falls. C M. euterpe n. sp., creek upstream Sagyimase. D M. cf. ventriosus (K. Viets, 1916), male, Laboun River. E – L Monatractides microstoma - species complex (E – G—Form '' A' ', H – L—Form '' B' '; E – H—ejaculatory complex reduced to sclerotized framework above the genital field, I – L ejaculatory complex slide-mounted): E, L = specimens from Tagbo River, F, H – K = specimens from Apkonu stream, G = specimen from Plunge pool Agumatsa Falls.