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 vietsi Koenike, 1911 ( Fig. 13 ) Material examined: 6 larvae deriving from 1 female . Very similar to A. neumani and A. affinis , but somewhat smaller; idiosoma 224–240 µm long. Subtle differences in dorsal plate shape. Dorsum : Dp (DpL: 210–240 µm ; DpW: 152–174 µm ) an ellipsoid shield, widest in mid-distance from anterior margin, clearly narrowed posteriorly. Anterior margin slightly convex, posterior margin sharpened. Antero-lateral indents deep, obtuse-angled, about 1/4 and 1/3 of plate’s length and width, respectively. DpW/ Mp1-Mp1 2.4. Mp1-Mp1 ( 50–59 µm ) equal to Mp2-Mp2 ( 51–57 µm ). Lp2, Mh1 pectinate. Venter : Lengths of median margins of Cp I, II , III at a ratio of 2.2:1:1.2. All setae on Cp bipectinate. Expp pentagonal, clearly wider than long. Exp in central location, distinctly above E2. Palps : PIII 1 bipectinate. Chelicerae : First segment elongated cylinder-shaped, slightly tapered anteriorly, margins somewhat bent. Legs as in A. neumani .