Monatractides (Monatractides) laosensis, Pešic & Smit, 2016

Pešic, V. & Smit, H., 2016, New records of water mites from Southeast Asia (Acari: Hydrachnidia) with the description of two new genera and 12 new species, Acarologia 56 (3), pp. 393-433 : 396-398

Monatractides (Monatractides) laosensis n. sp.

( Figure 2 )

Material examined — Holotype male, dissected and slide mounted, Laos, 15-33-1, Kouangxi Waterfall, lentic bay within a pond behind a travertine barrier within the main brook, 19°44’55.9"N, 101°59’33.4"E, alt. c. 490 m a.s.l., water depth 0.5 m, substrate: travertine mud covered by some leaves, 24.iv.2015.

Diagnosis — (Female unknown). Medial margin of Cx-II/III relatively short; P-4 stout with a strong dorsomedial peg-like seta, located away from the distal edge.

Description — Male: Idiosoma roundish; shoul- der platelet elongated (shoulder/frontal platelets L ratio 2.1-2.3); frontal platelet broad (L/W ratio 0.85 – 0.9); Cxgl-4 located far anteriorly, near tips of Cx- I; gnathosomal bay deep, U-shaped; medial margin of Cx-II/III relatively short; suture line of Cx- IV distinct, originating from lateral edge of genital field and extending posteriorly beyond posterior margin of genital field; genital field subrectangular, anteriorly enlarged and triangular; ejaculatory complex with small proximal chamber, carina anterior long; gnathosoma compact, rostrum truncated ( Figure 2F ); P-2 longer than P-4; distal margin of P-3 and P-4 medially and laterally with several pointed extensions; P-4 stout with a strong dorsomedial peglike seta, located away from the distal edge, ventral setae slender and short, not reaching the tip of P-5 ( Figures 2 C-D).

Measurements — Dorsal shield L 394, W 278, L/W ratio 1.42; shoulder plate L 147, W 59, L/W ratio 2.5; frontal plate L 64 – 70, W 75 – 77, L/W ratio 0.85 – 0.92; L shoulder/frontal plate ratio 2.1-2.3. Ventral shield L 431, W 409; gnathosomal bay L 130, Cx-I total L 216, Cx-I mL 84, Cx-II+III mL 47; ratio Cx-I L/Cx-II+III mL 2.6; Cx-I mL/Cx-II+III mL 1.8. Genital field L/W 119/97, ratio 1.23; ejaculatory complex L 80. Gnathosoma vL 111; chelicera total L 138; palp total L 159, dL/H, dL/H ratio: P-1, 20/25, 0.8; P-2, 47/34, 1.37; P-3, 28/27, 1.03; P-4, 39/18, 2.2; P-5, 25/11, 2.3; L P-2/P-4 ratio 1.2. Legs: dL of I-L: 46, 42, 46, 52, 54, 57; I-L-6 H 23, dL/H I-L-6 ratio 2.5.

Female: Unknown.

Etymology — Named after the country where the new species was found.

Remarks — The new species is characterized by the strong dorsomedial peg-like seta, located away from the distal edge of P-4. Due to the latter character, Monatractides laosensis n. sp. resembles M. (M.) koenikei (K. Viets, 1916), a species known from West Africa. The latter species can be distinguished in having three pairs of knob-like protrusions at the lateral margins of the moderately deep gnathosomal bay, a longer medial suture line of Cx-II+III and somewhat stouter palp segments, especially P- 4 (see Peši´c and Smit 2014a).

Distribution — Laos; known only from the locus typicus ( Figure 25A ).

Figures

FIGURE 2: Monatractides (Monatractides) laosensis n. sp., male, Kauangxi Waterfall, Laos: A – dorsal shield; B – idiosoma, ventral view; C – palp, medial view; D – palp, lateral view (P-1 lacking); E – ejaculatory complex; F – gnathosoma. Scale bars – 100 µm.

FIGURE 25: Photoghraphs of sampling sites: A – Laos, Kauangxi Waterfall (locus typicus of Monatractides laosensis n. sp., Hexaxonopsis laosensis n. sp., Sinaxonopsis laosensis n. sp. and Africasia purpurea n. sp.); B – Laos, Kouangxi Waterfall, pond behind artifical barrier (sampling site of Hygrobates hamatus K. Viets, 1935, H. henni Wiles, 2004 and locus typicus of Forelia gereckei n. sp.); C – Vietnam, Bach MAE National Park, brook with a pool (sampling site of Monatarctides sp. and locus typicus of Limnesia scharfi n. sp., Schwoerbelia pioniformis n. sp. and Arrenurus contortus n. sp.; D – Cambodia, moat around the main Angkor temple (locus typicus of Hexaxonopsis