Neoatractides uniscutatus, Pešić & Smit, 2014

Pešić, Vladimir & Smit, Harry, 2014, Torrenticolid water mites (Acari: Hydrachnidia: Torrenticolidae) from Malaysian Borneo, Zootaxa 3840 (1), pp. 1-72 : 32

Neoatractides uniscutatus n. sp.

( Figs. 20A–F , 22C–D , 23G )

Type series. Holotype male, dissected and slide mounted, Malaysia, Borneo , unnamed stream Bansadon Trail , Inobong, Crocker Range, 5º51.456 N, 116º68.403 E, 18.ix.2012 Smit.

Diagnosis (Female unknown). Frontal and shoulder plates fused with the large dorsal plate, but suture lines well visible; excretory pore and Vgl-1 embedded in the area of primary sclerotization; gnathosomal rostrum broad and upturned, narrower than remainder of the gnathosoma; P-4 stout (dL/H ratio 2.0).

Description

Male. General features —Frontal and shoulder plates fused with the large dorsal plate, but suture lines well visible ( Figs. 20A , 22C ); Cxgl–4 posterior to Cxgl–2; medial suture line of Cx-II+III moderately long; suture line of Cx-IV in medial part directed posteriorly, laterally curved; genital field subrectangular in shape; ejaculatory complex as photographed in Figure 23G ; excretory pore and Vgl–2 embedded in the area of primary sclerotization; P-1 with dorsal seta, P-2 and -3 without ventral projections, P-2 long with relatively short and slender ventral seta, lateral distal margin of P-3 deeply indented, P-4 stout, longer than P-3, dorsal margin strongly bowed, ventral margin concave with one long and one shorter seta ( Figs. 20C–D ). Gnathosoma without conspicuous oral papillae and short posterodorsal projections, rostrum broad and upturned, narrower than remainder of the gnathosoma ( Fig. 20E ); chelicera long with relatively short cheliceral claw (L basal segment/claw ratio 4.4). Legs: I-L with I-L-6 stout, L/H ratio 2.0, ventral margin distally strongly protruding ( Fig. 20F ).

Measurements —Idiosoma (ventral view: Figs. 20B , 22D ) L 556, W 414; dorsal shield ( Figs. 20A , 22C ) L 455, W 328, L/W ratio 1.39. Gnathosomal bay L 131, Cx-I total L 259, Cx-I mL 128, Cx-II+III mL 106; ratio Cx-I L/ Cx-II+III mL 2.4; Cx-I mL/Cx-II+III mL 1.2. Genital field L/W 93/70, ratio 1.32; distance genital field-excretory pore 78, genital field-caudal idiosoma margin 97. Gnathosoma vL 238–239; chelicera total L 263, basal segment L 220, claw L 50, L basal segment/claw ratio 4.4; palp total L 194–195, dL/H, dL/H ratio: P-1, 32/31–32, 1.03; P-2, 75/32, 2.36; P-3, 34/38, 0.9; P-4, 41–42/21, 2.0; P-5, 12/15, 0.8; P-2/P-4 ratio 1.82. Legs: dL of I-L-5–6: 85, 96, I- L-6 H 48, dL/H I-L-6 ratio 2.0.

Female: unknown.

Etymology. The species name refers to the undivided dorsal shield of the new species.

Discussion. Neoatractides uniscutatus n. sp. is the third representative of the subgenus Heteratractides Lundblad, 1941 . Synapomorphies of the species included in this subgenus (i.e. subgeneric autapomorphies) include the following features: lateral distal margin of P-3 deeply indented and gnathosomal rostrum broad and upturned ( Wiles 1997). Two species are known so far, Neoatractides serratirostris ( Lundblad, 1941) from Colombia ( Lundblad 1941) and N. orientalis Wiles, 1991 , described on the basis of two female specimens from Selangor, Peninsular Malaysia ( Wiles 1991, 1997). From the latter species, Neoatractides uniscutatus n. sp. can be distinguished by the frontal platelets fused to the large dorsal plate. Neoatractides serratirostris resembles the new species due to the anterolateral platelets fused with the large dorsal plate forming an undivided dorsal shield, but differs from the new species in having a shorter and broader gnathosomal rostrum, a very long ventral seta on P-2 exceeding the tip of P-5, a conventionally shaped ejaculatory complex, relatively larger genital field and a shorter medial suture line of Cx-II+III (see Lundblad 1953).

Habitat. Sandy/bouldery stream, shaded by rain forest ( Fig. 43B ).

Distribution. Borneo; known only from the locus typicus.

Genus Pseudotorrenticola Walter, 1906

Figures

FIGURE 20A–F. Neoatractides uniscutatus n. sp., male holotype, Kemantis stream: A = dorsal shield; B = idiosoma, ventral view; C = palp, medial view; D = palp, lateral view; E = gnathosoma and chelicera, F = I-L-5 and -6. Scale bars = 100 µm.

FIGURE 22A–F. Photographs of dorsal (A,C,E) and ventral shield (B,D,F). A–B Neoatractides sundaensis n. sp., female holotype, Kemantis stream. C–D Neoatractides uniscutatus n. sp., male holotype, Kemantis stream. E–F Pseudotorrenticola borneoensis n. sp., male holotype, Little Lumotok stream.

FIGURE 23A–H. Photographs of ejaculatory complex. A Torrenticola borneoensis n. sp. B T. kinabaluensis n. sp.. C T. longipalpis Wiles, 1997. D T. sabahensis n. sp. E Torrenticola minuta (Lundblad, 1941). F T. neoindica n. sp. G Neoatractides uniscutatus n. sp. H Pseudotorrenticola borneoensis n. sp.

FIGURE 43A–D. Photographs of selected sampling sites: A—Mahua stream (type locality of Torrenticola kinabaluensis n. sp. and sampling site of Torrenticola borneoensis n. sp., T. sabahensis n. sp., T. minuta, T. neoindica n. sp., T. cf. pugionirostris, Monatractides longiventris, M. parviventris and M. morpheus n. sp.), B—Unnamed stream Bansadon Trail (type locality of Neoatractides uniscutatus n. sp. and sampling site of Torrenticola borneoensis n. sp., T. kinabaluensis n. sp., Monatractides cf. macroporus and M. parviventris). C—Kibamabangan River (type locality of Torrenticola schilthuizeni n. sp. and sampling site of Torrenticola borneoensis n. sp., T. kinabaluensis n. sp., T. minuta and T. neoindica n. sp., Monatractides cf. macroporus, M. oxystomus, M. parviventris and M. morpheus n. sp.). D—Kemantis stream (type locality of Torrenticola borneoensis n. sp., Neoatractides sundaensis n. sp. and Monatractides phantasos n. sp. and sampling site of T. minuta, Monatractides longiventris, M. parviventris and M. morpheus n. sp.). Photos. H. Smit.