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 buccinator (O.F. Müller, 1776) ( Fig. 28 ) Hydrachna buccinator O.F. Müller, 1776 Hydrachna elliptica O.F. Müller, 1776 Acarus caudatus de Geer, 1778 Acarus aquaticus maculatus de Geer, 1778 Material examined: 10 larvae deriving from 10 females . Larvae medium-sized: idiosoma 200–216 µm long. Dorsum : Dp medium-sized (DpL: 194–206 µm ; DpW: 152–155 µm ), egg-shaped, widest at 1/3 of length. Antero-lateral indents large, strongly obtuse-angled, about 1/4 and 1/3 of plate’s length and width, respectively. DpW/Mp1-Mp1 4.0. Lp2, Mh1 smooth. Mp1-Mp1 relatively short ( 36–42 µm ), equal to Mp2-Mp2 ( 38–40 µm ); Mp1-Lp2 relatively short ( 36–41 µm ). Venter : CpIIm ( 25–29 µm ) distinctly shorter than CpIIIm ( 37–40 µm ), CpIm being longest ( 65–73 µm ). CpI:CpII:CpIII ratio 2.6:1:1.5. All setae on Cp bipectinate. C1- CpIm ( 22–24 µm ) about 6/7 of C4-CpIIIm ( 25–28 µm ). C1-C2 relatively short ( 31–36 µm ). Expp triangular, wider than long. Exp located distinctly below plate’s mid-point, but somewhat above E2 which are placed very low on plate. Palps : PIII 1 bipectinate. Chelicerae : First segment elongated and curved ( 76–81 µm ), its margins tending to converge anteriorly. Legs : As long as body; LI= LII < LIII ( Fig. 6 ). ITi7 thick; ITi8 long, pectinate; IITi8 very long; IITi10, IIITi10 located near mid-point of tibia. Hosts : Culicidae, Chaoboriddae , Chironomidae , Tanypodidae ( Stechmann 1976 /77, 1978).