Vicinaxonopsis costata, Smit, 2016

Smit, H., 2016, The water mite family Aturidae Thor, 1900 from Southeast Asia (Acari: Hydrachnidia) with the description of one new genus and 14 new species, Acarologia 56 (3), pp. 341-365 : 362-364

Vicinaxonopsis costata n. sp.

( Figure 15 )

Material examined — Holotype female, Thorntip Waterfall, Kaeng Krachan NP, Thailand, 12°50.952N 99°18.498E, 29-xi-2007.

Diagnosis — Eyes absent, venter with distinctive longitudinal ridges.

Description — Female: Idiosoma brown coloured, dorsally 489 long and 373 wide, ventrally 467 long; eyes absent. Dorsal shield fused anteriorly with ventral shield, 373 wide; excretory pore fused with dorsal shield. Dorsal shield with A2, postocularia and four pairs of glandularia; due to rugosity of integument associated setae of dorsoglandularia not visible. Body pores of integument arranged in a rounded pattern in anterior part of dorsal shield; anterior part of dorsum with two pairs of large lateral papillae. Anterior coxae not extending to anterior idiosoma margin. Coxal suture lines obliterated. Apodemes of gnathosoma very long. Anterior to the fourth leg sockets a ridge extending to the lateral idiosoma margin. Venter with numerous distinctive longitudinal ridges. Between fourth leg sockets and genital field two pairs of glandularia, lying close to each other. Genital field with three pairs of acetabula; gonopore 60 long and 46 wide. Length of P1-5: 30, 50, 24, 50, 53. P4 stocky and ventrally somewhat bulging, with a long ventral seta; P5 long and slender. Length of I-leg-4-6: 52, 54, 56 (till tip of segment). Length of IV-leg-4-6: 80, 78, 56. Numbers of swimming setae: IV-leg-4 one, IV-leg-5 two. Male: Unknown.

Etymology — Named for the distinctive ridges of the venter.

Remarks — The combination of absence of eyes and the presence of longitudinal ridges is characteristic for the new species. Vicinaxonopsis caeca ( Smit and Peši´c, 2014) from Borneo has reduced lateral eyes and a different patterns of the anterior dorsal shield ( Smit and Peši´c 2014). Despite the absence of eyes, the distinctive brown colour of the idiosoma shows that this species is not hyporheic.

Figures

FIGURE 15: Vicinaxonopsis costata n. sp., holotype female: A – dorsum; B – venter; C – palp. Scale bars = 50 µm.