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 integrator (O. F. Müller, 1776) ( Fig. 46 ) Hydrachna integrator O. F. Müller, 1776 Arrenurus solidus Piersig, 1894 Material examined: 10 larvae deriving from 10 females . Larvae relatively large: idiosoma 220–236 µm long. Dorsum : Dp relatively large (DpL: 208–224 µm ; DpW: 180–188 µm ), egg-shaped, widest at mid-length, although almost as wide at 1/3 of its length, rounded in posterior part. Antero-lateral indents, slightly obtuseangled, relatively small, about 1/5 and 1/4 of plate’s length and width, respectively. DpW/Mp1-Mp1 4.6. Lp2, Mh1 smooth. Mp1-Mp1 intermediate ( 38–42 µm ), shorter than Mp2-Mp2 ( 50–61 µm ); Mp1-Lp2 very short ( 26–34 µm ). Venter : Median margins of CpI, CpII, CpIII 66–73, 32–37, 44– 51 µm long, respectively, their ratio 2:1:1.4. C2 bipectinate; remaining setae on Cp pectinate. C1-CpIm ( 19–21 µm ) about 2/3 of C4-CpIIIm ( 26–30 µm ). C1-C2 intermediate ( 42–46 µm ). Expp rhomboid in shape, its length almost equal to its width. Exp located much below plate’s mid-point and below E2. E1 situated far from anterior margin. Palps : PIII 1 bipectinate. PV3 pectinate. Chelicerae : First segment bottle-shaped ( 78–82 µm ), one margin concave, other convex. Legs : Shorter than body; LI= LII = LIII ( Fig. 5 ). ITi7, ITi8 smooth, thin, short; IIGe2, IIIGe2 relatively long and bipectinate. Hosts : Nematocera ( Münchberg 1938 ).