Monatractides phantasos, Pešić & Smit, 2014

Pešić, Vladimir & Smit, Harry, 2014, Torrenticolid water mites (Acari: Hydrachnidia: Torrenticolidae) from Malaysian Borneo, Zootaxa 3840 (1), pp. 1-72 : 57

Monatractides phantasos n. sp.

( Figs. 30G , 34A–G , 35A–D , 39F–G , 40F–G )

Type series. Holotype female, dissected and slide mounted, Malaysia, Borneo , stream Kemantis , Sayap, Mt Kinabalu, 6º09.841 N, 116º33.936 E, alt. 928 m asl., 16.ix.2012 Smit . Paratypes: one male, Great Lumotok stream, Mt Kinabalu, 6º09.336 N, 116º34.056 E, alt. 1087 m asl., 17.ix.2012 Smit, dissected and slide mounted .

Diagnosis. Idiosoma elongated-oval (dorsal shield L/W ratio 1.3); frontal plates broad (L/W ratio 1.4), shorter than shoulder plates (shoulder/frontal plate L ratio 1.3); gnathosomal bay V-shaped; ventral setae on P-4 short. Male: medial margin of Cx-II/III relatively short; ejaculatory complex conventional in shape with small proximal chamber.

Description

General features —Idiosoma elongated-oval; frontal plates broad ( Fig. 34B ), shorter than shoulder plates; frontal margin medially slightly convex, between flat, anterolaterally pointed protrusions ( Figs. 34A , 35A ); Cxgl-4 located far anteriorly, near tips of Cx-I; gnathosomal bay V-shaped, proximally pointed ( Figs. 34C , 12C ); suture line of Cx-IV distinct, originating from the lateral edge of the genital field and extending posteriorly beyond the posterior margin of the genital field; excretory pore and Vgl-2 away from the line of primary sclerotization, Vgl-2 slightly posterior to excretory pore; gnathosoma with long dorsal apodemes, rostrum truncated ( Fig. 34G ); P-2 and P-3 distal margins without pointed tips, P-4 ventral setae short, not reaching the tip of P-5, with small denticles near insertion ( Figs. 34D–E ). Male: medial margin of Cx-II/III relatively short; genital field subrectangular; ejaculatory complex: proximal and distal arms well developed, carina anterior long, proximal chamber small ( Fig. 30G ). Female: genital field large and pentagonal in shape, anteriorly enlarged, laterally slightly convex, tapering posteriorly.

Measurements

Female (holotype)—Idiosoma (ventral view: Fig. 40F ) L 813, W 647; dorsal shield ( Figs. 34B , 39F ) L 741, W 572, L/W ratio 1.3; dorsal plate L 641; shoulder plate L 211–213, W 103, L/W ratio 2.05–2.06; frontal plate L 166, W 116, L/W ratio 1.43, L shoulder/frontal plate ratio 1.27–1.28. Gnathosomal bay L 111, Cx-I total L 289, Cx-I mL 178, Cx-II+III mL 43; ratio Cx-I L/Cx-II+III mL 6.7; Cx-I mL/Cx-II+III mL 4.1. Genital field L/W 198/175, ratio 1.13; distance genital field-excretory pore 163, genital field-caudal idiosoma margin 275. Gnathosoma vL 154; palp: total L 184, dL/H, dL/H ratio: P-1, 29/21-22, 1.36; P-2, 47/33.5, 1.4; P-3, 35/28, 1.28; P-4, 48/20, 2.4; P-5, 25/11–12, 2.1; P-2/P-4 ratio 0.98. Legs: dL of I-L-2–6: 68, 72, 91, 100, 103, I-L-6 H 37, dL/H I-L-6 ratio 2.8.

Male (paratype)—Idiosoma (ventral view: Fig. 40G ) L 781, W 634; dorsal shield ( Figs. 35B , 39G ) L 725, W 556, L/W ratio 1.3; dorsal plate L 640; shoulder plate L 213–222, W 100–109, L/W ratio 2.0–2.1; frontal plates fused to form an elongated platelet, L/W 319/123, ratio 2.6. Gnathosomal bay L 116, Cx-I total L 288, Cx-I mL 172, Cx-II+III mL 72; ratio Cx-I L/Cx-II+III mL 4.0; Cx-I mL/Cx-II+III mL 2.34. Genital field L/W 163/138, ratio 1.18; ejaculatory complex L 228; distance genital field-excretory pore 158, genital field-caudal idiosoma margin 256. Palp: total L 187, dL/H, dL/H ratio: P-1, 30–31/21, 1.45; P-2, 49/34, 1.45; P-3, 35/26, 1.35; P-4, 48/19, 2.6; P-5, 25/11, 2.3; P-2/P-4 ratio 1.02. Legs: dL of I-L-2-6: 65, 72, 88, 97, 99, I-L-6 H 36, dL/H I-L-6 ratio 2.8.

Etymology. The species is named after Phantasos (Ancient Greek: Φάντασος) who was a spirit of dreams of fantasy, and who takes the shape of inanimate objects. 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. The combination of a broad frontal plates (L/W ratio 1.4) and moderately deep, V-shaped, gnathosomal bay, easily separates the new species from all other members of the genus. Due to the V-shaped, gnathosomal bay, Monatractides phantasos n. sp. somehow resembles M. oxystomus (K. Viets, 1935) and M. tobaensis (K. Viets, 1935) (see above). However these two species seem not to be closely related to the new species as they differ in a series of features: less broader frontal plates, frontal margin medially strongly concave between large anterolaterally pointed protrusions, gnathosomal bay more deep, moderately long medial margin of Cx-II/III, P-4 with long ventral seta exceeding distal edge and excretory pore and Vgl-2 shifted more away from the line of primary sclerotization.

Variability. Frontal plates in male fused to form an elongated platelet, but traces of fusion visible ( Figs. 35B , 39G ).

Habitat. Sandy/bouldery streams, shaded by rain forest ( Fig. 43D ).

Distribution. Borneo.

Figures

FIGURE 12A–D. Torrenticola neoindica n. sp. (A—male holotype; B–D—female paratype), Mahua stream: A–B = idiosoma, ventral view; C = palp, medial view; D = gnathosoma. Scale bars = 100 µm.

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.

FIGURE 34A–G. Monatractides phantasos n. sp., holotype female, stream Kemantis: A = frontal margin of idiosoma, dorsal view; B = dorsal shield; C = idiosoma, ventral view; D = palp, lateral view; E = palp, medial view; F = I-L-5 and -6; G = gnathosoma Scale bars = 100 µm.

FIGURE 35A–D. Monatractides phantasos n. sp., paratype male, Great Lumotok stream: A = frontal margin of idiosoma, dorsal view; B = dorsal shield; C = idiosoma, ventral view; D = palp, medial view. Scale bars = 100 µm.

FIGURE 39A–I. Photographs of dorsal shield. A–E Monatractides morpheus n. sp. (A–C stream Layang Layang; D–E Little Lumotok stream): A = male holotype; B = female paratype, C = female paratype; D = male, E = female. F–G M. phantasos n. sp: C = female holotype, Kemantis stream; G = male paratype, Great Lumotok stream. H M. phobetor n. sp., male holotype, Little Lumotok stream. I M. minuta n. sp., female holotype, Great Lumotok stream.

FIGURE 40A–I. Photographs of ventral shield. A–E Monatractides morpheus n. sp. (A–C stream Layang Layang; D–E Little Lumotok stream): A = male holotype; B = female paratype, C = female paratype; D = male, D = female. F–G M. phantasos n. sp: C = female holotype, Kemantis stream; G = male paratype, Great Lumotok stream. H M. phobetor n. sp., male holotype, Little Lumotok stream. I M. minuta n. sp., female holotype, Great Lumotok stream.

FIGURE 43A–D. Photographs of selected sampling sites: A—Mahua stream (type locality of Torrenticola kinabaluensis n. sp. and sampling site of Torrenticola borneoensis n. sp., T. sabahensis n. sp., T. minuta, T. neoindica n. sp., T. cf. pugionirostris, Monatractides longiventris, M. parviventris and M. morpheus n. sp.), B—Unnamed stream Bansadon Trail (type locality of Neoatractides uniscutatus n. sp. and sampling site of Torrenticola borneoensis n. sp., T. kinabaluensis n. sp., Monatractides cf. macroporus and M. parviventris). C—Kibamabangan River (type locality of Torrenticola schilthuizeni n. sp. and sampling site of Torrenticola borneoensis n. sp., T. kinabaluensis n. sp., T. minuta and T. neoindica n. sp., Monatractides cf. macroporus, M. oxystomus, M. parviventris and M. morpheus n. sp.). D—Kemantis stream (type locality of Torrenticola borneoensis n. sp., Neoatractides sundaensis n. sp. and Monatractides phantasos n. sp. and sampling site of T. minuta, Monatractides longiventris, M. parviventris and M. morpheus n. sp.). Photos. H. Smit.