Monatractides macroporus
Creators: name: Pešić, Vladimir
name: Smit, Harry
Publisher: name: Zenodo
Year: 2014
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Trombidiformes
Torrenticolidae
Monatractides
Monatractides macroporus

description: Monatractides cf. macroporus (K. Viets, 1935)
(Figs. 24A–D, 26B, 28F–G, 29F–G, 30C–D, Tabs. 2–3)
Atractides macroporus K. Viets 1935: 577.
Atractides macrognathus K. Viets 1935: 584 — Lundblad 1971: 320.
Material examined. Malaysia, Borneo, unnamed stream Bansadon Trail, Inobong, Crocker Range, 5º51.456 N, 116º08.403 E, alt. 436 m asl, 18.ix.2012 Smit 1/0/0 (mounted); small stream waterfall trail Inobong, 5º51.306 N, 116º08.292 E, alt. 482 m asl., 19.ix.2012 Smit 1/1/0 (mounted).
Compared material
Monatractides macroporus (K. Viets, 1935): Holotype ♂, SMF 4422 Torrenticola macropora ♂, type, K.Viets 47766, Sumatra, Ranau Urwaldbaches bei Aer Pisaup 22.1.1929; SMF 4431 Torrenticola macropora ♀, type, K.Viets 47763, Sumatra, Musi bei Aer Simpang, 650 m, 6.5.1929.
Monatractides macrognathus (K. Viets, 1935): SMF 4173 Torrenticola macrognatha 1♂, 2♀, K.Viets 47733, Java, Zufluβbaches des Ranoe Bedali, 2.11.1928.
Monatractides major (K. Viets, 1935): SMF 4173 Torrenticola macrognatha 1♂, 2♀, K.Viets 47733, Java, Zufluβbaches des Ranoe Bedali, 2.11.1928.
Morphology
Male. General features —Idiosoma elongated-oval; frontal plates equal or slightly longer than shoulder plates (shoulder/frontal plate L ratio 0.9); frontal margin medially pointed, between anterolaterally pointed apodemes; Cxgl–4 located far anteriorly, near tips of Cx-I; gnathosomal bay deep, narrow U-shaped (Fig. 24B); 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, 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 (Fig. 24C). Male: medial margin of Cx-II/III relatively short; genital field subrectangular in shape; ejaculatory complex (Figs. 30C–D): proximal and distal arms well developed, carina anterior long, proximal chamber small (Fig. 26B).
Measurements
Male (from unnamed stream Bansadon Trail, in parentheses some measurements of specimen from stream waterfall trail Inobong)—Idiosoma (ventral view: Fig. 29F) L 631 (637), W 394 (407); dorsal shield (Fig. 28F) L 503 (506), W 365 (370), L/W ratio 1.38 (1.37); dorsal plate L 453 (453); shoulder plate L 111–114 (125–128), W 56 (59–62), L/W ratio 2.0 (2.1); frontal plate L 128–131 (123–128), W 56–58 (59–61), L/W ratio 2.2–2.3 (2.0–2.2); shoulder/frontal plate L ratio 0.87 (0.98–1.03). Gnathosomal bay L/W 140 (134)/34 (31), ratio 4.1 (4.3), Cx-I total L 234 (239), Cx-I mL 94 (105), Cx-II+III mL 73 (61); ratio Cx-I L/Cx-II+III mL 3.2 (3.9); Cx-I mL/CxII+III mL 1.3 (1.7). Genital field L/W 116 (122)/91 (91), ratio 1.28 (1.35); ejaculatory complex L 154 (153); distance genital field-excretory pore 156 (150), genital field-caudal idiosoma margin 213 (216). Gnathosoma vL 132 (136); chelicera total L 143 (145); palp total L 143, dL/H, dL/H ratio: P-1, 20/16, 1.23; P-2, 40/31, 1.3; P-3, 31/ 26, 1.18; P-4, 37/19, 2.0; P-5, 15/9, 1.7; P-2/P-4 ratio 1.08. Legs: dL of I-I-2–6: 42 (45), 45 (45), 57 (57), 65 (66), 71 (71), I-L-6 H 29 (28), L/H I-L-6 ratio 2.5 (2.5).
In addition we give locality records and measurements of female specimens suspected to belong to M. cf. macroporus.
New records. Great Lumotok stream, Mt Kinabalu, 6º09.336 N, 116º34.056 E, alt. 1087 m asl., 17.ix.2012 Smit 0/1/0; Little Lumotok stream, Sayap, Mt Kinabalu, 6º09.467 N, 116º34.027 E, alt. 1069 m asl., 17.ix.2012 Smit 0/1/0; Kibamabangan River, at waterfall, Crocker Range, 5º51.280 N, 116º08.417 E, 433 m asl., 18.ix.2012 Smit 0/1/0.
Measurements
Female (from Little Lumotok stream, n = 1)—Idiosoma (ventral view: Fig. 29G) L 818, W 587; dorsal shield (Fig. 28G) L 681, W 488, L/W ratio 1.4; dorsal plate L 619; shoulder plate L 167–169, W 64–69, L/W ratio 2.5–2.6; frontal plate L 138–140, W 77, L/W ratio 1.8; shoulder/frontal plate L ratio 1.19–1.23. Gnathosomal bay L/W 173/34, ratio 5.1, Cx-I total L 322, Cx-I mL 148, Cx-II+III mL 53; ratio Cx-I L/Cx-II+III mL 6.1; Cx-I mL/ Cx-II+III mL 2.8. Genital field L/W 156/138, ratio 1.14; distance genital field-excretory pore 184, genital fieldcaudal idiosoma margin 184. Gnathosoma vL 208; chelicera total L 222; palp total L 179, dL/H, dL/H ratio: P-1, 25/23, 1.07; P-2, 52/37, 1.41; P-3, 38.5/28, 1.39; P-4, 41/18.5, 2.2; P-5, 22/11, 2.1; P-2/P-4 ratio 1.27. Legs: dL of I-I-4–6: 88, 92, 91–92, I-L-6 H 26.5, L/H I-L-6 ratio 3.45.
Remarks. The specimens from Borneo match the general morphology of Monatractides macroporus, a species described by K. Viets (1935) from Sumatra based on a single male and one female specimen under question mark. In the same paper Viets (1935) described two species, closely related to the latter, M. macrognathus (K. Viets, 1935) and M. macrognathus major (K. Viets, 1935). Lundblad (1971) considered the latter two species synonymous with M. macroporus. However, Wiles (1991) rejected the synonymization of the latter species with M. macroporus and raised M. macrognathus major to a full species. Monatractides major is characterized at first line in comparison with the two abovementioned species by having four dorsoglandularia incorporated in the area of primary sclerotization. Monatractides macroporus (as well the specimens examined from Borneo) has a narrower gnathosomal bay than M. macrognathus (compare measurements in Tables 2 and 3) but this character is known to be variable in this species (Lundblad 1971). At the time being we keep M. macrognathus as synonym of M. macroporus.
In comparison with the holotype of M. macroporus and specimens of M. macrognathus from Java (see Tables 2–3), males examined in our study are notably smaller, and differ in having much shorter shoulder plates, more or less equal in dimensions to frontal plates, stouter I-L-6 and anterior dorsoglandularia shifted far anterior from medial muscle scar (lying near anterior end of medial muscle scar in specimens from Java). Thus, our assignment of the specimens from Borneo to M. macroporus is tentative, and very probably specimens from Borneo belong to a new species. However, only with application of molecular techniques it will be possible to decide whether this is really just a variable species or a complex of several similar species.
Furthermore, as already stated by Pešić & Smit (2009b) understanding the taxonomic position of other species (M. macroporus (K. Viets, 1935), M. major (K. Viets, 1935), M. angulatus (Walter, 1928), M. minor Wiles, 1991, and M. nondescripta (Cook, 1966)) tentatively included in the so-called M. macroporus- complex is not possible without additional material from a wide area and/or without the application of molecular techniques.
Wiles (1999) reported a single specimen, which best fits the description of M. macrognathus in the River Temburong (North Brunei). He mentioned that “there are other specimens that are not such a good fit and their status must await further investigation”.
Distribution. Sumatra (“ Atractides macroporus, A. macrognathus ” K. Viets 1935), Java (“ A. macrognathus ” K. Viets 1935, “ Torrenticola macropora ” Lundblad 1971). New for Borneo.
description: Published as part of Pešić, Vladimir & Smit, Harry, 2014, Torrenticolid water mites (Acari: Hydrachnidia: Torrenticolidae) from Malaysian Borneo, pp. 1-72 in Zootaxa 3840 (1) on pages 42-44, DOI: 10.11646/zootaxa.3840.1.1, http://zenodo.org/record/4927892