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 knauthei Koenike, 1895 ( Fig. 36 ) Material examined: 5 larvae deriving from 1 female . Larvae very large: idiosoma 260–318 µm long. Dorsum : Dp very large (DpL: 260–302 µm ; DpW: 228–240 µm ), oval, widest at mid-length. Anterior margin short, almost straight; posterior margin somewhat blunt. Antero-lateral indents very small, somewhat obtuse-angled, about 1/7 and 1/5 of plate’s length and width, respectively. DpW/Mp1-Mp1 5.3. Lp2, Mh1 smooth. Mp1-Mp1 intermediate ( 42–50 µm ), shorter than Mp2-Mp2 ( 70–74 µm ); Mp1-Lp2 short ( 36–40 µm ). Venter : Cp very long: CpIm, CpIIm, CpIIIm 86–90, 41–46, 54– 60 µm long, respectively, their ratio 2:1:1.3. Postero-lateral margins of CpIII strongly indented due to large size of excretory pore plate. Setae on Cp pectinate. C1-CpIm ( 22–26 µm ) about 2/3 of C4-CpIIIm ( 35–38 µm ). C1-C2 very long ( 66–70 µm ). Expp oval, somewhat wider than long. Exp located slightly below plate’s mid-point, level with or slightly above E2. E1 located relatively far from anterior margin of Expp. Palps : PIII 1 bipectinate; PIV1 long, pectinate; PV6 long. Chelicerae : First segment long, cylindrical ( 129–140 µm ), slightly narrowing anteriorly, one margin somewhat concave, other slightly convex. Legs : Shorter than body; LI= LII = LIII ( Fig. 5 ). ITi8 short, thin; IIGe3, IIIGe3 relatively thick and bipectinate. IIITa11, IIITa12, IIITa13 pectinate. IITi10, IIITi10 smooth, located about 1/3 away from distal end of tibia. Hosts : Culicidae (Münchberg 1936) .