Torrenticola tjiwalensis (K. Viets, 1935 )

Pešić, Vladimir & Smit, Harry, 2014, Torrenticolid water mites (Acari: Hydrachnidia: Torrenticolidae) from Malaysian Borneo, Zootaxa 3840 (1), pp. 1-72 : 22-25

Torrenticola tjiwalensis (K. Viets, 1935)

( Figs. 14A–D , 16E , 17E )

Atractides tjiwalensis K. Viets 1935: 595 . New records. Malaysia, Borneo , Mahua stream, downstream of national park entrance, Crocker Range, 5º46.491 N, 116º25.770 E, alt. 865 m asl., 22.ix.2012 Smit 1/0/0 (mounted); unnamed stream Bansadon Trail, Inobong, Crocker Range, 5º51.456 N, 116º68.403 E, 18.ix.2012 Smit 0/1/0 ((bar-coded).

Morphology

Male. General features —Idiosoma elongated-oval (dorsal shield L/W ratio 1.3-1.4); gnathosomal bay Ushaped, proximally pointed; Cxgl-4 subapical, only slightly posterior of Cx-I tips; genital field subrectangular; posterior suture lines of Cx-IV starting at right angle from genital field; excretory pore away from the line of primary sclerotization, excretory pore on the level with Vgl-2; gnathosomal rostrum shortened, ventral margin in lateral view curved ( Fig. 14D ); P-2 ventral margin with a denticulation also in proximal half of the segment, distally with a small, laterally compressed, anteriorly directed and apically serrated hyaline extension (rudimentary flange, Wiles 1997) and a very short, denticle-like seta laterally at base of projection; P-3 with a subrectangular, apically serrated ventrodistal projection, and a very long seta (longer than P-3) laterally at base of projection; P-4 stout, with ventral tubercles pointed and separated, bearing one long and three short setae ( Figs. 14 B-C).

Measurements —Idiosoma (ventral view: Figs. 14A , 17E ) L 522, W 397; dorsal shield ( Fig. 16E ) L 438, W 322, L/W ratio 1.36; dorsal plate L 403; shoulder plate L 131-138, W 50-54, L/W ratio 2.5-2.6; frontal plate L 91- 95, W 45-47, L/W ratio 2.0–2.03; shoulder/frontal plate L 1.44–1.45. Gnathosomal bay L 86, Cx-I total L 189, CxI mL 103, Cx-II+III mL 94; ratio Cx-I L/Cx-II+III mL 2.0; Cx-I mL/Cx-II+III mL 1.1. Genital field L/W 122/97, ratio 1.26; ejaculatory complex L 168; distance genital field-excretory pore 78, genital field-caudal idiosoma margin 111. Gnathosoma vL 246; chelicera total L 266; palp total L 246, dL/H, dL/H ratio: P-1, 26/28, 0.94; P-2, 69/51, 1.36; P-3, 55/46, 1.2; P-4, 75/29, 2.58; P-5, 21/11, 1.9; P-2/P-4 ratio 0.93.

Remarks. The specimens from this study matches the general morphology of Torrenticola tjiwalensis (K. Viets, 1935) , a species originally described from Java (K. Viets 1935), and later on reported from Peninsular Malaysia ( Wiles 1997) and Borneo ( Wiles 1999). The differences with the original description (in parentheses, from K. Viets 1935) are found in slightly smaller dimensions, stouter P-4 and the excretory pore lying on the same level as Vgl-2 (shifted slightly posterior to Vgl-2) of the specimen from Borneo. Thus, our assignment of the specimen from Borneo is tentative. Only with more material in the future it will be possible to decide whether this is really just a variable species or a complex of several similar species.

Distribution. Java (K. Viets 1935), Peninsular Malaysia ( Wiles 1997), Borneo ( Wiles 1999, our study)

Figures

FIGURE 14A–D. Torrenticola tjiwalensis (K. Viets, 1935), male, Mahua stream: A = idiosoma, ventral view; B = palp, medial view (P-1 lacking); C = palp, lateral view; D = gnathosoma. Scale bars = 100 µm.

FIGURE 16A–F. Photographs of dorsal shield. A–B Torrenticola minuta (Lundblad, 1941): A = male, Kemantis stream; B = female, Great Lumotok stream. C–D T. neoindica n. sp., Mahua stream: C = male holotype; D = female paratype. E T. tjiwalensis (K. Viets, 1935), male, Mahua stream. F. T. schilthuizeni n. sp., female holotype, Kibamabangan River.

FIGURE 17A–F. Photographs of ventral shield. A–B Torrenticola minuta (Lundblad, 1941): A = male, Kemantis stream; B = female, Great Lumotok stream. C–D T. neoindica n. sp., Mahua stream: C = male holotype; D = female paratype. E T. tjiwalensis (K. Viets, 1935), male, Mahua stream. F T. schilthuizeni n. sp., female holotype, Kibamabangan River.