Arrenurus securiformis Piersig, 1894

Zawal, Andrzej, 2008, Morphological characteristics of water mite larvae of the genus Arrenurus Dugès, 1834, with notes on the phylogeny of the genus and an identification key, Zootaxa 1765 (1), pp. 1-75 : 51

Arrenurus securiformis Piersig, 1894

( Fig. 33 )

Arrenurs festivus Koenike, 1895

Material examined: 10 larvae deriving from 1 female.

Larvae medium-sized: idiosoma 200–210 µm long.

Dorsum: Dp egg-shaped (DpL: 186–204 µm; DpW: 152–162 µm), widest at mid-length. Antero-lateral indents almost right-angled, about 1/5 and 1/4 of plate’s length and width, respectively. DpW/Mp1-Mp1 4.4. Lp2, Mh1 smooth. Mp1-Mp1 (34–38 µm) somewhat shorter than Mp2-Mp2 (38–42 µm), their ratio 1.1. Venter: CpI:CpII:CpIII ratio is 2.3:1:1.7. All setae on Cp smooth. C1-CpIm clearly shorter than C4-CpIIIm, reaches to about 5/7 of it. C1-C2 intermediate length (42–44 µm). Expp triangular in outline, of roughly equal length and width. Exp located below plate’s mid-point and slightly below E2. Palps: PIII 1 smooth; PV7 large. Chelicerae: First segment cylindrical in shape (78–81 µm), distal end slightly curved and somewhat convergent margins. Legs: As long as body; LI< LII < LIII ( Fig. 3 ). ITi7 thin; ITi8 intermediate length; IITi7, IITi8, IIITi7, IIITi8 thin, smooth. IITi10, IIITi10 located at about 1/3 of distance from distal end of tibia. IIITa8 absent. Hosts: Chironomidae , Tanypodidae ( Stechmann 1976 /77, 1978).

Figures

FIGURE 3. Diagram of proportions of leg (LI<LII<LIII) and body length.

FIGURE 33. Arrenurus securiformis: A—ventral side, B—dorsal plate, C—excretory pore plate, D—pedipalp, E—leg I (scale bars: A, B—100 µm; C, D—20 µm; E—50 µm).