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 forpicatus Neuuman, 1880 ( Fig. 44 ) Arrenurus nonforpicatus George, 1903 Material examined: 10 larvae deriving from 3 females . Larvae large: idiosoma 242–264 µm long. Dorsum : Dp egg-shaped (DpL: 234–254 µm ; DpW: 200–232), widest at mid-point. Antero-lateral indents very small, strongly obtuse-angled, about 1/7 and 1/5 of plate’s length and width, respectively. Anterior margin of plate very narrow, length about 1/5 of plate’s width. DpW/Mp1-Mp1 5.8. Lp2, Mh1 smooth. Mp1-Mp1 short ( 36–38 µm ), much shorter than Mp2-Mp2 ( 50–56 µm ); Mp1-Lp2 short ( 35–38 µm ). Venter : CpIm long ( 90–98 µm ), followed by CpIIm ( 41–50 µm ) and short ( 28–30 µm ) CpIIIm. CpI:CpII:CpIII ratio 3.2:1.6:1. All setae on Cp smooth. C1-CpIm ( 22–24 µm ) somewhat shorter than C4-CpIIIm ( 26–32 µm ), about 6/7 of it. C1- C2 very long ( 52–62 µm ). Expp pentagonal, somewhat wider than long. Exp located below plate’s mid-point and below E2. Palps : PIII 1 thick, bipectinate; PV3, PV4, PV5 pectinate; PV7 very long. Chelicerae : First segment long, cylinder-shaped ( 115–117 µm ), strongly bent at distal end, margins slightly convergent. Legs : As long as body; LI< LLII < LIII ( Fig. 3 ). ITi8, ITi7 thin, short; IGe2, IIGe2, IIIGe2 relatively long; IGe2, IIGe2, IIIGe2, IIITi3, IIITi5 relatively thick; IIITa8 present.