Schwoerbelia pioniformis, 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 : 410-412

Schwoerbelia pioniformis n. sp.

( Figure 11 )

Type material — Holotype female, dissected and slide mounted, Vietnam, 15-44-1 Bach MAE National Park, brook with a pool behind a natural barrier, 16°11’15.5"N, 105°50’54.7"E, alt. 1130 m a.s.l., water depth 0.2 m, substrate: leaves in a lentic bay, 2.v.2015.

Diagnosis — (Male unknown). As for genus.

Description — Dorsum soft. All coxal setae slender; medial margin of Cx-III almost as long as medial margin of Cx-IV. Genital bay very shallow, gonopore very long, genital plates broad and rounded, with 5 pairs of small acetabula arranged along the plate margins, medial margin straight or slightly concave, pregenital sclerite small, triangular ( Figure 11A ); excretory pore smooth. P-3 with a very long lateral seta, P-4 with two long setae close to each other, and a peg-like mediodistal seta ( Figures 11 B-C); P-5 long (around 80 % L of P-4); gnathosoma with posterior anchoral process. Legs: number of swimming setae: I-L-1, 1 (short); II-L-4, 2; II-L-5, 2-3; III-L-4, 3; III-L-5, 3; IV-L-4, 3; IV-L-5, 3-4; IV-L-3-5 each with one strong ventrodistal pennate seta ( Figure 11F ).

Measurements — Idiosoma L/W 638/538; coxal field L/W 253/291; genital field L/W 165/214; genital plate L/W 51-52/38; gonopore L 148, pregenital sclerite W 29. Palp: total L 179, dL/H, dL/H ratio: P-1, 19/25, 0.75; P-2, 49/39, 1.28; P-3, 31/30, 1.05; P- 4, 48/22, 2.2; P-5, 32/12, 2.6; dL ratio P-2/P-4, 1.03; gnathosoma vL 49, with anchoral process 85; chelicera total L 75. Legs: dL of I-L: 41, 48, 66, 91, 98, 103; dL of IV-L: 52, 55, 68, 97, 115, 119.

Etymology — The name of the new species refers to its resemblance with Piona species.

Distribution — Vietnam; known only from the locus typicus ( Figure 25C ).

Figures

FIGURE 11: Schwoerbelia pioniformis n. gen., n. sp., female, Bach MAE National Park, Vietnam: A – idiosoma, ventral view; B-C – palp; D – gnathosoma; E – I-L-5 and -6; F – IV-L. 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