Arrenurus cylindratus Piersig, 1896

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 : 52

Arrenurus cylindratus Piersig, 1896

( Fig. 34 )

Arrenurus latigenitalis Lundblad, 1956

Material examined: 10 larvae deriving from 10 females.

Larvae medium-sized: idiosoma 196–208 µm long.

Dorsum: Dp intermediate in size (DpL: 188–200 µm; DpW: 160–170 µm), egg-shaped, widest at about 1/ 3 of distance from almost straight anterior margin; posterior margin sharpened. Antero-lateral indents relatively deep, somewhat obtuse-angled, about 1/4 of Dp length and width. DpW/Mp1-Mp1 4.5. Lp2, Mh1 smooth. Mp1-Mp1 relatively short (36–38 µm), shorter than Mp2-Mp2 (40–44 µm); Mp1-Lp2 relatively short (32–37 µm). Venter: CpIm clearly longest (68–71 µm), CpIIm shortest (26–29 µm), CpIIIm intermediate length (42–45 µm); proportions 2.5:1:1.5. Setae on idiosoma smooth. C1-CpIm (24–28 µm) about 5/6 of C4- CpIIIm (28–32 µm). C1-C2 (42–45 µm) intermediate length. Expp triangle-shaped, sides convex, clearly wider than long. Exp located distinctly below plate’s mid-point, but above E2. Palps: PIII 1 smooth. Chelicerae: First segment bottle-shaped (77–79 µm), one margin straight, other convex. Legs: As long as body; LI< LII < LIII ( Fig. 3 ). IFe3 pectinate, ITi7, ITi8 thick, IITi10, IIITi10 located in middle of tibia, IIITa3 placed near middle of tarsus.

Figures

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

FIGURE 34. Arrenurus cylindratus: A – ventral side, B—dorsal plate, C—excretory pore plate, D—leg I (scale bars: A, B—100 µm; C, D—20 µm).