Atractides (Atractides) crockerensis, n. sp.
Creators: name: Smit, Harry
name: Pešić, Vladimir
Publisher: name: Zenodo
Year: 2014
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Trombidiformes
Hygrobatidae
Atractides
Atractides crockerensis

description: Atractides (Atractides) crockerensis n. sp.
(Figs. 16A–E, 17A–B)
Type series. Holotype male, dissected and slide mounted, Mahua river, upper course, Borneo, Malaysia, 5° 47.939 N 116° 24.317 E, 1050 m asl., 21.ix.2012 (RMNH). Paratypes: two females, Mahua stream, Mahua, Crocker Range, Borneo, Malaysia, 5° 47.838 N 116° 24.510 E, alt. 1052 m asl., 21.ix.2012 (RMNH), one female dissected and slide mounted; one male, Kibamabangan River, Crocker Range, Borneo, Malaysia, 5°51.280 N, 116°08.417 E, alt. 433 m asl., 18-ix-2012 (RMNH).
Diagnosis. Dorsal muscle insertions sclerotized, forming two paired and one unpaired plate(s) in males, four paired plates in females; ventral surface covered by an extended shield incorporating coxae, vgl-1–4, genital field, V-1–4 and excretory pore; palp without sexual dimorphism, ventral margins P2–3 straight; S-1 and -2 distanced, S-1 long and slender, S-2 distinctly shorter, I-leg-6 slender.
Description. Integument dorsally striated, muscle insertions sclerotized dorsally: postoc + D-1 + dgl-3 fused, dgl–4 + D-3 fused, D-4 separate in female (Fig. 17A) but fused to each other in male (Fig. 16A), all plates rather large, but enlarged in male than in female (maximum diameter D3 103 in male, 94 in female). Coxal field: ventral surface covered by an extended shield including coxae, V-1-4, vgl-1-4, genital field and excretory pore (Figs. 16B, 17B). Palp: no sexual dimorphism; ventral margins P2-3 straight, P4 sword seta between ventral setae insertions, ventral sectors nearly equal in length (Figs. 16C–D). Legs: I-leg-5 with ventral and dorsal margins diverging from base to S-1 insertion, in the extended area between S-1 and -2 subparallel, S-1 and -2 distanced, S-1 long and slender, distally equally narrowed, tip slightly truncated, S-2 distinctly shorter, thicker than S-1, tip bluntly pointed, I-leg-6 slender, basally slightly thickened, narrowed in the centre, with dorsal and ventral margins subparallel centrally and distally (Fig. 16E).
Measurements. Male (holotype)—Idiosoma length/width 453/308, glandularia diameter 34; coxal field: Cx-III width 253; genital field: width between most lateral pair of Ac 100, length Ac 1–3: 25–26, 28–31, 25–28, ejaculatory complex length 69.
Palp: Total length 220, dorsal length/height, dorsal length/height ratio: P1, 20/18, 1.13; P2, 48/33, 1.44; P3, 55/ 29, 1.87; P4, 69/15, 4.5; P5, 28/9.5, 2.9; length P-2/P-4 ratio 0.69. Capitulum length 77; chelicera total length 138.
Legs: I-leg-5 dorsal length 112, ventral length 72, dorsal length/ventral length ratio 1.55, maximum height 34, dorsal length/maximum height 3.3, S-1 length 75, length/width ratio 9.7, S-2 length 57, length/width ratio 6.2, distance S- 1-2 17, length ratio S-1/2 1.3; I-leg-6 length 91, central height 13.5, length/central height ratio 6.7; length I-leg-5/6 ratio 1.23.
Female (paratype)—Idiosoma length/width 516/369, glandularia diameter 36; coxal field: Cx-III width 283; genital field: width between most lateral pair of Ac 131, length Ac 1–3: 24–27, 29–32, 26–30; egg (n = 1) maximum diameter 119.
Palp: Total length 242–243, dorsal length/height, dorsal length/height ratio: P1, 21–22/18–19, 1.16; P2, 55/34, 1.6; P3, 65/31.5, 2.0; P4, 71/19, 3.7; P5, 30/11.5, 2.6; length P-2/P-4 ratio 0.77; chelicera total length 141.
Legs: I-leg-5 dorsal length 136, ventral length 88, dorsal length/ventral length ratio 1.54, maximum height 36, dorsal length/maximum height 3.8, S-1 length 89, length/width ratio 9.9, S-2 length 62, length/width ratio 5.0, distance S- 1–2 25, length ratio S-1/2 1.45; I-L-6 length 117, central height 12, length/central height ratio 9.9; length I-leg-5/6 ratio 1.16.
Etymology. Named after the mountain (Crocker Range) where the new species was detected.
Discussion. The new species resembles Atractides ventridurus (K. Viets, 1935) (Western and Central Java, K. Viets 1935) due to extended ventral sclerotization in the male, which incorporates the coxae, vgl-1–4, genital field, V-1-4 and excretory pore, and the similar shape of palp and I-leg-5 and - 6 in both sexes. The latter species can be distinguished in both sexes by the absence of sclerotized dorsal muscle insertions, and in the female sex also by the absence of an extended ventral shield.
Distribution. Borneo.
description: Published as part of Smit, Harry & Pešić, Vladimir, 2014, Water mites from Mount Kinabalu and the Crocker Range, Borneo, Malaysia (Acari: Hydrachnidia), with the description of 34 new species, pp. 1-71 in Zootaxa 3876 (1) on pages 29-31, DOI: 10.11646/zootaxa.3876.1.1, http://zenodo.org/record/287281