Morphological characteristics of water mite larvae of the genus Arrenurus Dugès, 1834, with notes on the phylogeny of the genus and an identification key Author Zawal, Andrzej text Zootaxa 2008 2008-05-07 1765 1 1 75 https://biotaxa.org/Zootaxa/article/view/zootaxa.1765.1.1 journal article 10.11646/zootaxa.1765.1.1 1175­5334 5123752 Arrenurus cuspidator (O. F. Müller, 1776) ( Fig. 17 ) Arrenurus decippiens Piersig, 1895 Material examined: 10 larvae deriving from 10 females . Larvae medium-sized: idiosoma 196–204 µm long. Dorsum : Dp relatively small, its size highly variable (DpL: 166–202 µm ; DpW: 124–146 µm ); eggshaped; anterior margin almost straight, posterior margin rounded. Antero-lateral indents deep, about 1/4 of DpL, and almost right-angled. DpW/Mp1-Mp1 2.5. Lp2, Mh1 thin, smooth. Mp1-Mp1 relatively long ( 52–61 µm ), longer than Mp2-Mp2 ( 42–44 µm ); Mp1-Lp2 relatively short ( 34–42 µm ). Venter : CpIIm ( 28–30 µm ) and CpIIIm ( 24–28 µm ) almost equal length; CpIm ( 61–67 µm ) twice as long. C1, C3 bipectinate; C2, C4 pectinate. C1, C4 located close to median margins of coxal plates. C1-CpIm ( 13–18 µm ) somewhat more than a half of C4-CpIIIm ( 22–28 µm ). C1-C2 relatively long ( 45–50 µm ). Expp pentagonal, almost as wide as long. Exp situated distinctly below mid-point of plate and below E2. Palps : PIII 1 bipectinate. Chelicerae : First segment bottle-shaped ( 70–76 µm ), one margin flat, other convex. Legs : as in A. cuspidator . Hosts : Lestes sponsa , Coenagrion hastulatum , C. puella , C. pulchellum , Erythromma najas , Ischnura elegans , ( Davids 1997 ; Rolf et al. 2000 , 2001 ; Baker et al. 2006 ; Baker et al. 2007 ).