Monatractides morpheus, Pešić & Smit, 2014

Pešić, Vladimir & Smit, Harry, 2014, Torrenticolid water mites (Acari: Hydrachnidia: Torrenticolidae) from Malaysian Borneo, Zootaxa 3840 (1), pp. 1-72: 54-56

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Monatractides morpheus

n. sp.

Monatractides morpheus   n. sp.

( Figs. 30I–L View FIGURE 30 , 31A–G View FIGURE 31 , 32A–B View FIGURE 32 , 33A–H View FIGURE 33 , 39A–E View FIGURE 39 , Tab. 5 View TABLE 5 )

Type series. Holotype male, dissected and slide mounted, Malaysia, Borneo , small stream Layang Layang, Mt Kinabalu, 6º02.711 N, 116º33.627 E, alt. 2697 m asl., 12.ix.2012 Smit GoogleMaps   . Paratypes: 5(2juv.)/11/0, same data as holotype, two males and three females GoogleMaps   of them dissected and slide mounted.

Further records. Malaysia, Borneo : first stream Minduk Sirung Trail , Alab , Crocker Range , 5º49.249 N, 116º19.862 E, alt. 1781 m asl., 23.ix.2012 Smit 2/2/0 (2/0/0 mounted); Kibamabangan River , GoogleMaps   Crocker Range, 5º51.280 N, 116º08.417 E, 433 m asl., 18.ix.2012 Smit 2/3/0; Mahua stream, Mahua, GoogleMaps   Crocker Range, 5º47.838 N, 116º24.510 E, alt. 1052 m asl., 21.ix.2012 Smit 3/2(1 ov, 1 juv)/0; stream Kemantis, Sayap, GoogleMaps   Mt Kinabalu , 6º09.841 N, 116º33.936 E, alt. 928 m asl., 16.ix.2012 Smit 1/1/0 (1/0/0 mounted); Great Lumotok stream, GoogleMaps   Mt Kinabalu , 6º09.336 N, 116º34.056 E, alt. 1087 m asl., 17.ix.2012 Smit 4/3/0; Little Lumotok stream, Sayap, GoogleMaps   Mt Kinabalu , 6º09.467 N, 116º34.027 E, alt. 1069 m asl., 17.ix.2012 Smit 3/3/0 (2/2/0 mounted); Rheocrene along Little Lumotok stream, Sayap, GoogleMaps   Mt Kinabalu , 6º09.440 N, 116º34.026 E, 17.ix.2012 Smit 1/0/0; Silau-Silau stream, upstream, GoogleMaps   Mt Kinabalu , 6º00.681 N, 116º32.417 E, alt. 1592 m asl., 11.ix.2012 Smit 1/0/0 (mounted); Liwagu River , upstream, GoogleMaps   Mt Kinabalu , 6º01.868 N, 116º32.912 E, alt. 1919 m asl., 11.ix.2012 Smit 2/0/0; spring near helipad, Summit Trail, GoogleMaps   Mt Kinabalu, 6º03.199 N, 116º33.957 E, alt. 3048 m asl., 14.ix.2012 Smit 0/1/0; small stream Panar Laban Hut GoogleMaps   Mt Kinabalu, 6º03.641 N, 116º33.968 E, 3330 m asl., 13.ix.2012 Smit 1/1/0; torrential stream crossing main road Alab-Kota Kinabalu, GoogleMaps   Crocker Range, 5º50.039 N, 116º20.156 E, alt. 1571 m asl., 24.ix.2012 Smit 0/1/0 GoogleMaps   .

Diagnosis. Idiosoma elongated (dorsal shield L/W ratio 1.4); shoulder plates only slightly longer than frontal plates (shoulder/frontal plate L ratio 1.03–1.04); gnathosomal bay U-shaped; excretory pore well anterior to Vgl-2 and away from the line of primary sclerotization; ventral setae on P-4 short. Male: medial margin of Cx-II/III relatively short; genital field, large and elongated (L/W ratio 1.4); ejaculatory complex with large proximal chamber, proximal and distal arms short.


General features —Idiosoma elongated; shoulder plates only slightly longer than frontal plates; frontal margin medially slightly convex between large anterolaterally pointed apodemes ( Fig. 31A View FIGURE 31 ); Cxgl-4 located far anteriorly, near tips of Cx-I; gnathosomal bay deep, U-shaped; 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 well separated from the line of primary sclerotization, Vgl-2 posterior to excretory pore; nearly triangular in lateral view, rostrum truncated ( Fig. 31F View FIGURE 31 ); P-2 and P-3 distal margins without pointed tips, P-4 ventral setae short, not reaching the tip of P-5 ( Figs. 31D–E View FIGURE 31 ). Male: medial margin of Cx-II/III relatively short; genital field subrectangular, large and elongated (L/W ratio 1.4); ejaculatory complex ( Figs. 30I–L View FIGURE 30 , 33F–G View FIGURE 33 ) characteristic, proximal chamber large, proximal and distal arms short. Female: genital field large and pentagonal in shape, anteriorly enlarged, laterally straight, tapering posteriorly.


Male (holotype; in parentheses paratype from small stream Layang Layang, n = 1)—Idiosoma (ventral view: Figs. 31C View FIGURE 31 , 40A View FIGURE 40 ) L 913 (797), W 681 (591); dorsal shield ( Figs. 31B View FIGURE 31 , 39A View FIGURE 39 ) L 806 (719), W 578 (503), L/W ratio 1.4 (1.4); dorsal plate L 756 (679); shoulder plate L 173 (166–169), W 72–74 (67–69), L/W ratio 2.3–2.4 (2.4–2.5), frontal plate L 168–169 (147–154), W 67 (63), L/W ratio 2.5 (2.4–2.5); L shoulder/frontal plate ratio 1.03–1.04 (1.08–1.15). Gnathosomal bay L 187 (170), Cx-I total L 350 (313), Cx-I mL 163 (142), Cx-II+III mL 45 (43); ratio Cx-I L/Cx-II+III mL 7.8 (7.3); Cx-I mL/Cx-II+III mL 3.6 (3.3). Genital field L/W 200 (195)/143 (139), ratio 1.4; ejaculatory complex L 250 (244); distance genital field-excretory pore 169 (147), genital field-caudal idiosoma margin 301 (240). Gnathosoma vL 203 (188); chelicera total L 248 (211); palp total L 249 (226), dL/H, dL/H ratio: P-1, 37/29, 1.25 (34/29, 1.16); P-2, 72/46, 1.56 (63/47, 1.33); P-3, 49/39, 1.26 (45/38, 1.17); P-4, 63/29, 2.18 (59/ 27, 2.19); P-5, 28/15, 1.8 (25/14, 1.8); P-2/P-4 ratio 1.15 (1.07). Legs: dL of I-L-2–6: 85, 98, 133, 129, 132, I-L-6 H 48, dL/H I-L-6 ratio 2.8.

Female (paratype from small stream Layang Layang, n = 1)—Idiosoma (ventral view: Figs. 32A View FIGURE 32 , 40B View FIGURE 40 ) L 881, W 663; dorsal shield ( Fig. 39B View FIGURE 39 ) L 773, W 556, L/W ratio 1.4; dorsal plate L 734; shoulder plate L 170–172, W 70, L/W ratio 2.4–2.5; frontal plate L 162–163, W 59, L/W ratio 2.7; L shoulder/frontal plate ratio 1.05–1.06. Gnathosomal bay L 169, Cx-I total L 306, Cx-I mL 138, Cx-II+III mL 31; ratio Cx-I L/Cx-II+III mL 9.9; Cx-I mL/ Cx-II+III mL 4.5. Genital field L/W 226/188, ratio 1.21; distance genital field-excretory pore 172, genital fieldcaudal idiosoma margin 302. Gnathosoma vL 216; chelicera total L 241; palp total L 233, dL/H, dL/H ratio: P-1, 32/30, 1.08; P-2, 65.5/48, 1.36; P-3, 48/41.5, 1.15; P-4, 63/30, 2.09; P-5, 24/-; P-2/P-4 ratio 1.04; Legs: dL of I-L2–6: 80, 94, 122, 122, 119, I-L-6 H 42, dL/H I-L-6 ratio 2.8.

Etymology. The species is named after Morpheus (Ancient Greek: Μορφεύς), who was a spirit of dreams, and who takes the shape of humans. 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 morpheus   n. sp. resembles the M. luteus (K. Viets, 1935)   —complex characterized in the first line in comparison with the species of M. macroporus   –complex (see above) by the presence of anteriorly broad and short Cx-I and relatively wide gnathosomal bay ( Pešić & Smit 2010). This group includes five similar species known from Java, i.e., M. luteus (K. Viets, 1935)   , M. roseus ( Lundblad, 1941)   , M. landbergi ( Lundblad, 1941)   , M. parvus ( Lundblad, 1941)   and M. longiusculus ( Lundblad, 1941)   . From all abovementioned species the new species from Borneo can easily be distinguished by the characteristic morphology of the ejaculatory complex (proximal chamber large, proximal and distal arms short, carina anterior short versus normally-developed with small proximal chamber in the species from Java (see Lundblad 1956, 1971).

There appear to be two forms of this species which can be identified in the female sex. At one extreme end, females with an enlarged genital field and less extended postgenital area ( Fig. 40B View FIGURE 40 ). At the other extreme end specimens with a less enlarged genital field and more extended postgenital area ( Fig. 40C View FIGURE 40 ). The figures 32A–B illustrate two specimens collected from the locus typicus.

The specimens from Little Lumotok stream and Kemantis stream ( Table 5 View TABLE 5 ) differ from the type specimens by broader frontal plates ( Fig. 33B View FIGURE 33 , 39D–E View FIGURE 39 ), slightly longer medial suture line of Cx-II+III, smaller dimensions of genital field and broader I-L-6 ( Fig. 33H View FIGURE 33 ) These differences could reflect some degree of genetical differentiation between these populations. Unfortunately, our effort to obtain sequences of the mtCOI fragment from different populations of this species from Borneo were not successful. On the other hand introducing a new species for both forms, in our opinion, will create more confusion given the present state of knowledge of this species.

Habitat. Sandy/bouldery streams, shaded by rain forest ( Figs. 43A,C–D View FIGURE 43 ).

Distribution. Borneo.