Monatractides epiales, Pešić & Smit, 2014

Pešić, Vladimir & Smit, Harry, 2014, Torrenticolid water mites (Acari: Hydrachnidia: Torrenticolidae) from Malaysian Borneo, Zootaxa 3840 (1), pp. 1-72 : 52-53

Monatractides epiales n. sp.

( Figs. 25A–G , 26A , 27A–B , 28H–I , 29H–I , 30E–F )

Type series. Holotype male, dissected and slide mounted, Malaysia, Borneo , Kipungit River , Poring Hot Springs, Mt Kinabalu, 6º02.776 N, 116º41.432 E, 568 m asl., 15.ix.2012 Smit . Paratypes: one male, same data as holotype, dissected and slide mounted .

Other material: one female dissected and slide mounted same data as holotype .

Diagnosis. Male. Idiosoma elongated-oval (dorsal shield L/W ratio 1.3–1.4); frontal plates similar in dimensions to shoulder plates (shoulder/frontal plate L ratio 0.99–1.04); gnathosomal bay deep, narrow U-shaped (L/W ratio 4.6); medial margin of Cx-II/III relatively short; genital field elongated (L/W ratio 1.3–1.4); ejaculatory complex with large proximal chamber, proximal and distal arms short; excretory pore anterior to Vgl–2 and away from the line of primary sclerotization; ventral setae on P-4 short.

Description

Male. General features —Idiosoma elongated-oval; frontal plates similar in dimensions to shoulder plates; frontal margin medially pointed, between anterolaterally pointed apodemes ( Fig. 25A ); Cxgl–4 located far anteriorly, near tips of Cx-I; gnathosomal bay deep, narrow U-shaped ( Fig. 25C ); medial margin of Cx-II/III relatively short; genital field subrectangular in shape; ejaculatory complex characteristic ( Figs. 26A , 30E–F ), proximal chamber large, proximal and distal arms short, carina anterior short; suture line of Cx-IV distinct, originating from lateral edge of genital field and extending posteriorly beyond posterior margin of genital field; excretory pore and Vgl–2 away from the line of primary sclerotization, Vgl–2 slightly posterior to excretory pore; gnathosoma elongated in lateral view ( Fig. 25F ), rostrum truncated; ventral and dorsal setae of P-2 and P-3 relatively strong and long, P-2 and P-3 distal margins without pointed tips, P-4 ventral setae short ( Figs. 25D–E ).

Measurements

Male (holotype; in parentheses paratype, n = 1)—Idiosoma (ventral view: Figs. 25C , 29H ) L 618 (591), W 394 (369); dorsal shield ( Figs. 25B , 28H ) L 477 (453), W 363 (331), L/W ratio 1.31 (1.37); dorsal plate L 429 (408); shoulder plate L 124–127 (113), W 52–56 (50–53), L/W ratio 2.2–2.4 (2.1–2.3); frontal plate L 122–125 (111), W 53–55 (47–52), L/W ratio 2.3 (2.2–2.4); shoulder/frontal plate L ratio 0.99–1.04 (1.0). Gnathosomal bay L/W 148 (128)/31 (28), ratio 4.8 (4.6); Cx-I total L 250 (227), Cx-I mL 101 (98), Cx-II+III mL 66 (58); ratio Cx-I L/CxII+III mL 3.8 (3.9); Cx-I mL/Cx-II+III mL 1.5 (1.7). Genital field L/W 119 (111)/87 (83), ratio 1.37 (1.34); ejaculatory complex L (166); distance genital field-excretory pore 138 (141), genital field-caudal idiosoma margin 183 (195). Gnathosoma vL 147 (138); chelicera total L 160 (148); palp total L 149 (147), dL/H, dL/H ratio: P-1, 21.5/15, 1.4 (21.5/17, 1.3); P-2, 41.5/31, 1.35 (39/26, 1.5); P-3, 33/26, 1.27 (32/23, 1.4); P-4, 36/17, 2.14 (37/17, 2.19); P-5, 17/9, 1.84 (17/9, 1.85); P-2/P-4 ratio 1.15 (1.06). Legs: dL of I-L-2–6: 45, 52 (52), 65 (65), 69 (69), 71 (68), I-L-6 H 28.5 (26), L/H I-L-6 ratio 2.5 (2.6).

At present, it is impossible to give an unequivocal diagnosis for the female of M. epiales n. sp. In the following list, measurements are given for a female taken at the locus typicus of M. epiales n. sp. —Idiosoma (ventral view: Figs. 27A , 29I ) L 700, W 430; dorsal shield ( Fig. 28I ) L 553, W 409, L/W ratio 1.35; dorsal plate L 500; shoulder plate L 122–127, W 64–67, L/W ratio 1.9; frontal plate L 131, W 61–66, L/W ratio 2.0–2.2; shoulder/frontal plate L ratio 0.93–0.96. Gnathosomal bay L 148, Cx-I total L 253, Cx-I mL 106, Cx-II+III mL 46; ratio Cx-I L/Cx-II+III mL 5.5; Cx-I mL/Cx-II+III mL 2.3. Genital field pentagonal in shape, anteriorly enlarged, laterally straight, tapering posteriorly, L/W 150/130, ratio 1.16; distance genital field-excretory pore 175, genital field-caudal idiosoma margin 250. Gnathosoma vL 138–139; chelicera total L 159; palp ( Fig. 27B ) total L 155, dL/H, dL/H ratio: P-1, 22/17, 1.3; P-2, 43/32, 1.35; P-3, 33/26, 1.27; P-4, 40/18.5, 2.16; P-5, 17/9, 1.87; P-2/P-4 ratio 1.08. Legs: dL of I-L-4–6: 62, 69, 71, I-L-6 H 30, L/H I-L-6 ratio 2.4.

Etymology. The species is named after Epiales (Ancient Greek: Ἐπιάλης), who was a spirit of nightmares. The species name is a noun in apposition (in the nominative case), despite the Recommendation 31A of the ICZN (1999) about avoidance of personal names as nouns in appositions, because there is no case for it being confusing or misleading.

Discussion. Monatractides epiales n. sp. is rather similar and probably represent a sister species of M. macroporus (K. Viets, 1935) (see above) with respect to the general shape of idiosoma and palps. Main differences between M. macroporus and M. epiales n. sp. are found in the morphology of ejaculatory complex (normallydeveloped with small proximal chamber in M. macroporus vs. proximal chamber large, proximal and distal arms short, carina anterior short in M. epiales n. sp. —compare Figs. 26A and -B ). The female assigned to M. epiales n. sp. can be identified on the basis of a relatively larger extension of the genital field (L ratio genital/idiosoma 0.21).

Habitat. Sandy/bouldery stream, shaded by rain forest

Distribution. Borneo; known only from the locus typicus.

Figures

FIGURE 25A–G. Monatractides epiales n. sp., holotype male, Kipungit River: A = frontal margin of idiosoma, dorsal view; B = dorsal shield; C = idiosoma, ventral view; D = palp, medial view; E = palp, lateral view; F = gnathosoma; G = I-L-5 and -6. Scale bars = 100 µm.

FIGURE 26A–B. Ejaculatory complex. A = Monatractides epiales n. sp., Kipungit River. B = M. cf. macroporus (K. Viets, 1935), unnamed stream Bansadon Trail. Scale bar = 100 µm.

FIGURE 27A–B. Monatractides epiales n. sp., female, Kipungit River: A = idiosoma, ventral view; B = palp, medial view. Scale bars = 100 µm.

FIGURE 28A–I. Photographs of dorsal shield. A–B Monatractides longiventris (K. Viets, 1939), Mahua stream: A = male; B = female. C–D M. parviventris (K. Viets, 1935): C = female, stream Bansadon Trail; D = male, Kemantis stream. E M. oxystomus (K. Viets, 1935), male, Kipungit River. F–G M. cf. macroporus (K. Viets, 1935): F = male, stream Bansadon Trail; G = female, Little Lumotok stream. H–I M. epiales n. sp., Kipungit River: H = male; I = female.

FIGURE 29A–I. Photographs of ventral shield. A–B Monatractides longiventris (K. Viets, 1939), Mahua stream: A = male; B = female. C–D M. parviventris (K. Viets, 1935): C = female, stream Bansadon Trail; D = male, Kemantis stream. E M. oxystomus (K. Viets, 1935), male, Kipungit River. F–G M. cf. macroporus (K. Viets, 1935): F = male, stream Bansadon Trail; G = female, Little Lumotok stream. H–I M. epiales n. sp., Kipungit River: H = male; I = female.

FIGURE 30A–M. Photographs of ejaculatory complex. A Monatractides longiventris (K. Viets, 1939), Mahua stream. B M. oxystomus (K. Viets, 1935), Kipungit River. C–D M. cf. macroporus (K. Viets, 1935): C = stream Bansadon Trail; D = Little Lumotok stream. E–F M. epiales n. sp., Kipungit River: E = holotype; F = paratype. G M. phantasos n. sp., Great Lumotok stream. H M. phobetor n. sp., Little Lumotok stream. I–L M. morpheus n. sp. I = holotype, small stream Layang Layang; K = Kemantis stream; K = Little Lumotok stream. M M. heracles n. sp., Little Lumotok stream.