Arrenurus affinis Koenike, 1887

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 : 25

Arrenurus affinis Koenike, 1887

( Fig. 11 )

Arrenurus rufescens Croneberg, 1899

Material examined: 10 larvae deriving from 10 females.

Larvae relatively large; idiosoma 230–244 µm long.

Dorsum: Dp (DpL: 224–236 µm, DpW: 172–184 µm) shield-shaped, sharpened posteriorly. Antero-lateral indents deep, obtuse-angled, 1/5 and 1/4 dorsal plate’s length and width, respectively. DpW/Mp1-Mp1 2.8. Mp1-Mp1 (62–65 µm) longer than Mp2-Mp2 (58–63 µm). Lp2, Mh1 pectinate. Venter: CpI:CpII:CpIII ratio 2.4:1:1.4. All setae on Cp and V 3 bipectinate. C1-CpIm (22–23 µm) about 2/3 of C4-CpIIIm (38–39 µm). C1- C2 short (38–42 µm). Expp pentagonal, distinctly broader than elongated. Exp in middle of plate, clearly above E2 setae. Palps: PIII 1 bipectinate; PV7 large. Chelicerae: first segment elongate cylinder-shaped (104– 106 µm), slightly tapered anteriorly, one margin distinctly curved, other straight or slightly curved. Legs: Longer than body; LI< LII < LIII ( Fig.3 ). ITi7 thin and long; ITa7, ITa8, ITa9, ITa10, ITa12, IITi10, IITa7, IITa8, IITa9, IITa10, IITa12, IIITa5, IIITa6, IIITa7, IIITa8, IIITa9, IIITa11, IIITa12, IIITa13 pectinate; IFe1, IFe3, IIFe1, IIFe3, IIIFe3 bipectinate. IITi10, IIITi10 situated near mid-point of tibia. IITa8 present. Hosts: Coenagrion puella (L.), C. pulchellum (Vander L.) , Erythromma najas (Hansem.) , Pyrrhosoma nymphula (Sulz.) , Enallagma cyathigerum (Charp.) ( Davids 1997) .

Figures

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

FIGURE 11. Arrenurus affinis: A—ventral side, B—dorsal plate, C—excretory pore plate, D—pedipalp (scale bars: A, B—100 µm; C, D—20 µm).