Arrenurus sinuator (O. F. Müller, 1776)

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 : 66

Arrenurus sinuator (O. F. Müller, 1776)

( Fig. 49 )

Hydrachna sinuator O. F. Müller, 1776

Arrenurus similis Pisarovic, 1896

Arrenurus hungaricus Daday, 1897

Material examined: 10 larvae deriving from 10 females.

Larvae large (idiosoma 240–258 µm long) and very similar to those of A. biscissus .

Dorsum: Dp large (DpL: 236–244 µm; DpW: 190–200 µm), egg-shaped, widest at mid-length. Antero-lateral margins very small, almost invisible, obtuse-angled, about 1/5 and 1/7 of plate’s width and length, respectively. DpW/Mp1-Mp1 4.4. Lp2, Mh1 smooth. Mp1-Mp1 long (42–50 µm), but shorter than Mp2-Mp2 (58– 64 µm); Mp1-Lp2 intermediate (38–45 µm). Venter: CpIm longest (86–96 µm), followed by CpIIm (53–60 µm); CpIIIm (21–25 µm) very short; ratio 4:2.5:1. All setae on Cp bipectinate ( Fig. 1 ). C1-CpIm (26–28 µm) about 3/4 of C4-CpIIIm (37–40 µm). C1-C2 intermediate (42–46 µm). Expp rhomboid, characteristic process in lower part (process may not be visible) and an anterior depression. Exp located distinctly below plate’s mid-point and below E2. Palps: PIII 1 thick, bipectinate. PV4, PV5 bipectinate from about 1/3 their length; PV4 long, thin, PV5 thicker and shorter. Chelicerae: First segment elongated and curved cylinder-shaped (88– 92 µm), margins parallel. Legs: As long as body; LI< LII < LIII ( Fig. 3 ). IFe4, IGe2, IGe3, ITi3, ITi7, IIFe4, IIGe2, IIGe3, IIGe4, IITi3, IITi7, IITi8, IIIFe3, IIIGe2, IIIGe4, IIITi2, IIITi3, IIITi6, IIITi7 relatively thick and bipectinate. ITi8 long, thin; IITi10, IIITi10 pectinate, located close to mid-point of tibia. Hosts: Chironomidae , Tanypodidae ( Stechmann 1976 /77, 1978).

Figures

FIGURE 1. Arrenurus maculator: A—ventral side, B—dorsal side, C—excretory pore plate, D—pedipalp, E—chelicera, F—leg I, G—leg II, H—leg III (scale bars: A, B—100 µm; C, D—10 µm; E—50 µm; F, G, H—20 µm).

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

FIGURE 49. Arrenurus sinuator: A—ventral side, B—dorsal plate, C—excretory pore plate, D—pedipalp (scale bars: A, B—100 µm; C, D—20 µm).