Atractides (Tympanomegapus) borneoensis, Smit, Harry & Pešić, Vladimir, 2014

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, Zootaxa 3876 (1), pp. 1-71 : 35-36

Atractides (Tympanomegapus) borneoensis n. sp.

( Figs. 20A–E )

Type series. Holotype male, dissected and slide mounted, Mahua stream, Mahua, Crocker Range, Borneo, Malaysia, 5º 47.838 N 116º 24.510 E, alt. 1052 m asl., 21.ix.2012 ( RMNH).

Diagnosis. Male (female unknown): Some of the dorsal muscle insertions sclerotized (a pair of elongated platelets including postoc, D-1 and D-2, but dgl-3 free, D-3 fused with dgl-4); Cx-IV with broad border of secondary sclerotization including vgl-3 and vgl-4, vgl-1 separate from vgl-2; P4 sword seta little enlarged, but not hair-like, P5 without “cheeks”. I-leg-6 stout and weakly curved, ventral margin proximally concave, distally protruding; claws with ventral and dorsal clawlets.

Description. Male. Integument finely striated; dorsal muscle insertions sclerotized ( Fig. 20A ): a pair of elongated platelets including postoc, D-1 and D-2, but dgl-3 free, D-3 fused with dgl-4, D-4 as areas of granulate integument, other glandularia on extended platelets. Coxal field: posteromedial margin of Cx-I+II pointed, apodemes of Cx-II short, directed posterolaterally, Cx-IV with broad border of secondary sclerotization incorporating vgl-3 and vgl-4 ( Fig. 20B ). Genital field: with a convex, medially protruding border of primary sclerotization, posterior margin slightly indented, Ac in triangular arrangement. Excretory pore smooth; vgl-1 separate from vgl-2. Palp: P4 with straight ventral and equally curved dorsal margins, sword seta pointed, little enlarged, but not hair-like, inserting distal to distoventral seta, P5 without “cheeks” ( Fig. 20C ). Legs: I-leg-5 S-1 and -2 closely together; I-leg-6 strong and thick, weakly curved, narrowed in the centre of the segment, maximum height at base of claw furrow; claws with ventral and dorsal clawlets ( Fig. 20E ).

Measurements —Idiosoma length/width 456/322, glandularia diameter 30; coxal field: length 341; Cx-III width 270; Cx-I+II medial length 153, lateral length 228; genital field length/width 95/112, length Ac 1–3: 28–31, 27–29, 31.

Palp: Total length 221, dorsal length/height, dorsal length/height ratio: P1, 34/11.5, 2.9; P2, 46/28, 1.67; P3, 45/24, 1.84; P4, 67/15, 4.35; P5, 29/10, 2.9; length P2/P4 ratio 0.69. Capitulum length 129; chelicera total length 163, claw length 57, basal segment length 152, length basal segment/claw ratio 2.67.

Legs: I-leg-5 dorsal length 88, ventral length 65, dorsal length/ventral length ratio 1.36, maximum height 28, dorsal length/maximum height 3.2, S-1 length 34, length/width ratio 8.7, S-2 length 35, length/width ratio 7.6, distance S-1–2 3.0, length ratio S-1/2 0.97; I-leg-6 length 74, central height 20, length/central height ratio 3.7; length I-leg-5/6 ratio 1.19.

Female: Unknown.

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

Remarks. The male of Atractides borneoensis n. sp. shares with A. talinarostris Cook, 1967 (Maharashtra State, India) the absence of dorsal and ventral shields, leg claws with dorsal clawlet, sword seta on P4 enlarged, not hair-like, absence of “cheeks” on P5, and capitulum not particularly elongated. The latter species differs in the fusion of vgl-1+2, and a more slender I-leg-6 (see Cook 1967). The presence of a little enlarged, not hair-like sword seta on P4 is also found in A. neoclipeatus Lundblad, 1971 (Java) and A. sulawesiensis Pešić & Smit, 2009 (Sulawesi) , both known only in the female sex. They differ in a more elongated capitulum, A. neoclipeatus furthermore in the leg claws lacking dorsal clawlet, and A. sulawesiensis in the presence of cheeks on P5.

Distribution. Borneo; known only from the locus typicus.

Figures

FIGURE 20 A – E. Atractides borneoensis n. sp., Mahua stream, male holotype: A = idiosoma, dorsal view; B = idiosoma, ventral view; C = palp, medial view; D = capitulum and chelicera; E = I-leg- 5 and - 6. Scale bars = 100 Μm.