Torrenticola borneoensis, Pešić & Smit, 2014

Pešić, Vladimir & Smit, Harry, 2014, Torrenticolid water mites (Acari: Hydrachnidia: Torrenticolidae) from Malaysian Borneo, Zootaxa 3840 (1), pp. 1-72 : 6-8

Torrenticola borneoensis n. sp.

( Figs. 2A–D , 3A–B , 9A–B , 10A–B , 23A )

Type series. Holotype male, dissected and slide mounted, Malaysia, Borneo , stream Kemantis , Sayap, Mt Kinabalu, 6º09.841 N, 116º33.936 E, alt. 928 m asl., 16.ix.2012 Smit . Paratypes: two females, same data as holotype , one female dissected and slide mounted.

Further records. Malaysia, Borneo , Mahua stream, Mahua , Crocker Range , 5º47.838N, 116º24.510E, alt. 1052 m asl., 21.ix.2012 Smit 1/0/0; unnamed stream Bansadon Trail, Inobong, Crocker Range, 5º51.456 N, 116º68.403 E, 18.ix.2012 Smit 1/0/0; Kipungit River , Poring Hot Springs, Mt. Kinabalu, 6º02.776 N, 116º41.432 E, 568 m asl., 15.ix.2012 Smit 2/1/0; Kibamabangan River, Crocker Range, 5º51.28 N, 116º08.417 E, 433 m asl., 18.ix.2012 Smit 1/0/0 .

Diagnosis. Idiosoma roundish (dorsal shield L/W ratio 1.3); shoulder platelets fused to the large dorsal plate; Cxgl–4 far posterior at margin of Cx-I/II, near I–L insertion; P-2 with a laterally compressed, anteriorly directed ventrodistal extension covering less than 30% of ventral margin.

Description

General features —Idiosoma roundish; shoulder platelets fused to the large dorsal plate; dorsal shield with colour pattern as illustrated in Figs. 9A–B ; gnathosomal bay U-shaped, proximally rounded; Cxgl–4 far posterior at margin of Cx-I/II, near I–L insertion; suture lines of Cx-IV extending posteriorly beyond posterior margin of genital field, laterally curved; excretory pore away from the line of primary sclerotization, Vgl–2 on the same level or slightly posterior from excretory pore; gnathosomal rostrum long and slender, ventral margin in lateral view curved ( Fig. 2D ); P-2 slightly shorter than P-4, P-2 ventral margin convex, distally with a laterally compressed, anteriorly directed and apically serrated hyaline extension (covering less than 30% of ventral margin) and a very short, denticle-like seta laterally at base of projection; P-3 with a shorter, subrectangular, apically serrated ventrodistal projection, and a long seta laterally at base of projection; P-4 slender, with ventral tubercles pointed and separated, bearing one long and three short setae ( Figs. 2C , 3B ). Male: medial suture line of Cx-II+III relatively long; genital field subrectangular, ejaculatory complex with small proximal chamber ( Fig. 23A ). Female: genital field pentagonal in shape.

Measurements

Male (holotype)—Idiosoma (ventral view: Figs. 2B , 10A ) L 666, W 469; dorsal shield ( Figs. 2A , 9A ) L 525, W 413, L/W ratio 1.27; dorsal plate L 490; frontal plate L 129–131, W 45–46, L/W ratio 2.8–2.9. Gnathosomal bay L 128, Cx-I total L 250, Cx-I mL 122, Cx-II+III mL 120; ratio Cx-I L/Cx-II+III mL 2.1; Cx-I mL/Cx-II+III mL 1.02. Genital field L/W 123/97, ratio 1.27; distance genital field-excretory pore 122, genital field-caudal idiosoma margin 171. Gnathosoma vL 302; chelicera total L 334; palp total L 287, dL/H, dL/H ratio 287: P-1, 29/25, 1.18; P-2, 92/55, 1.69; P-3, 57/45, 1.26; P-4, 94/24, 3.86; P-5, 15/11, 1.43; P-2/P-4 ratio 0.98.

Female (paratype)—Idiosoma (ventral view: Figs. 3A , 10B ) L 720, W 506; dorsal shield ( Fig. 9B ) L 594, W 450, L/W ratio 1.32; dorsal plate L 556; frontal plate L 148–151, W 49–50, L/W ratio 3.03. Gnathosomal bay L 125, Cx-I total L 250, Cx-I mL 108, Cx-II+III mL 108; ratio Cx-I L/Cx-II+III mL 2.3; Cx-I mL/Cx-II+III mL 1.0. Genital field L/W 134/128, ratio 1.05; distance genital field-excretory pore 166, genital field-caudal idiosoma margin 266. Gnathosoma vL 335; chelicera total L 368; palp total L 311, dL/H, dL/H ratio: P-1, 35/27, 1.32; P-2, 100/62, 1.61; P-3, 55/49, 1.13; P-4, 106/24, 4.37; P-5, 15/11, 1.43; P-2/P-4 ratio 0.94.

Etymology. Named after the island where the new species was detected.

Discussion. Torrenticola borneoensis n. sp belongs to the former subgenus Rusetria Thor, 1897 , characterized by the fusion of the shoulder platelets with the large dorsal plate. Together with Torrenticola indica Cook, 1967 ( India; Cook 1967), T. flangia Wiles, 1997 (Sulawesi; Wiles 1997, Pešić & Smit 2011), T. kinabaluensis n. sp. (see below) and T. neoindica n. sp. (see below), T. borneoensis n. sp. belongs to a group characterized by a flanged palp (P-2 with a laterally compressed and apically serrated ventrodistal extension). The combination of a flanged palp with Cxgl-4 shifted close to I-L insertion makes the new species similar to T. kinabaluensis n. sp. (see below). The latter species can easily be distinguished by a more elongated dorsal shield and the flange on P-2 more longish (>30% of ventral margin of P-2). Further, Cxgl-4 is shifted more posteriorly in T. kinabaluensis n. sp., lying between I- and –II–L insertions, but more approaching I–L. Torrenticola flangia resembles T. kinabaluensis n. sp. in the shape of the palp (flange on P-2 longish,> 30% of ventral margin) but clearly differs from both aforementioned new species from Borneo in a characteristic colour pattern on the dorsal shield (typically with a broad posterior and a narrow anterior band of blue pigment) and Cxgl–4 more posterior, lying in close proximity to Cxgl–2 (see Wiles 1997).

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

Distribution. Borneo.

Figures

FIGURE 2A–D. Torrenticola borneoensis n. sp., holotype male, stream Kemantis: A = dorsal shield; B = idiosoma, ventral view; C = palp, medial view; D = gnathosoma. Scale bars = 100 µm.

FIGURE 3A–B. Torrenticola borneoensis n. sp., paratype female, stream Kemantis: A = idiosoma, ventral view; B = palp, lateral view. Scale bars = 100 µm.

FIGURE 9A–I. Photographs of dorsal shield. A–B Torrenticola borneoensis n. sp., Kemantis stream: A = male holotype; B = female paratype. C–D T. kinabaluensis n. sp.: C = male holotype; D = female paratype, Little Lumotok stream. E–F T. longipalpis Wiles, 1997, male, Mahua stream. G–I T. sabahensis n. sp.: G = male holotype; H = male, Little Lumotok stream; I = female paratype, Great Lumotok stream.

FIGURE 10A–I. Photographs of ventral shield. A–B Torrenticola borneoensis n. sp., Kemantis stream: A = male holotype; B = female paratype. C–E T. kinabaluensis n. sp.: C = male holotype; D = male paratype, Little Lumotok stream; E = female paratype, Little Lumotok stream. F T. longipalpis Wiles, 1997, male, Mahua stream. G–I T. sabahensis n. sp.: G = male holotype; H = male, Little Lumotok stream; I = female paratype, Great 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.