Larval morphology of Arrenurus cuspidifer Piersig, A. claviger Koenike, and A. latus Barrois & Moniez (Acari: Hydrachnidia) Author Zawal, Andrzej text Zootaxa 2006 1276 55 68 journal article 10.5281/zenodo.173333 e4bc0cd0-a1b8-4be5-9e50-d5b676cf9d3f 1175­5326 173333 Arrenurus latus Barrois & Moniez, 1887 (30) ( Fig. 3 , Tables 1 , 2 ) Arrenurus ligulator Koenike, 1905 (550) Material examined: Progeny from a single female collected from a ploughed field near Kiczorowo, Stargard Szczeciński district, Poland , 53o30’N , 15o14’E , among reed­marshes, 30 July 1998 . Diagnosis: Dorsal plate elliptic with fairly deep anterior­lateral indentations which reach to about one­fifth of the plate length and one­third of its width; CpI median margins twice as long as the other, CpII and CpIII median margins equal; Expp oval, its width equal to its length, Exp located near the centre of the plate and posterior to alveoli of the E2 setae; PV3 and PV4 pectinate; IGe3 and IIGe3 fairly thick and bipectinate; IITi10 smooth and IIITi10 pectinate, both located near the centre of tibia. Description: The size of the body is fairly large ( Table 1 ). The elliptic dorsal plate is widest in the middle of its length and narrows at the posterior. The anterior margin is slightly convex and the posterior margin is pointed. Anterior­lateral indentations are fairly deep, with obtuse angles, and reach to about one­fifth of the plate length and one­third of its width. The Lpl seta is tripartite and the remaining setae are smooth ( Fig. 3 ). The CpI median margins are twice as long as the other, the CpII and CpIII median margins are equal. All the setae on the coxal plates are smooth. Distance between the C4 seta and the CpIII median margin is 1.5 times longer than those between the C1 seta and CpI median margin. The distance between setae C1 and C2 is long ( Table 1 , Fig. 3 ), The excretory pore plate is oval, its width is equal to its length. The excretory pore is located near the centre of the plate and posterior to the alveoli of the E2 setae ( Table 1 , Fig. 3 ). The pedipalps in size and shape are typical for Arrenurus species. Seta PIII1 is bipectinate, PV3 and PV4 are pectinate and fairly long, PV6 is fairly thick, and PV8 is long ( Table 1 , Fig. 3 ). The first segment of the chelicera has the form of a slightly curved cylinder and narrows posteriorly ( Fig. 3 ). The proportions of segments are more or less the same for each leg. The shortest leg segment, the trochanter, constitutes about 2/3 of the femur, the genu is a little shorter than the femur, the tibia is 1.5 times longer and the tarsus twice as long ( Table 2 ). The tarsi of all legs, particularly the third, narrow posteriorly. Seta ITi8 is thin and long, IGe3 and IIGe3 are fairly thick and bipectinate, IITi8 and IIITi8 are fairly long and bipectinate. Seta IITi10 is smooth and IIITi10 is pectinate, both are located near the centre of the tibia ( Fig. 3 ).