Hydrachna sistanica, Pešić & Smit & Saboori, 2012

Pešić, Vladimir, Smit, Harry & Saboori, Alireza, 2012, 3330, Zootaxa 3330, pp. 1-67 : 7-9

Hydrachna sistanica sp. nov.

( Figs. 4, 5A – F)

Material examined. Holotype male (idiosoma in fluid, gnathosoma, palp and I/IV-legs dissected and slide mounted), Iran, Sistan va Baluchestan Province, IR5-2011, Gerdoig village N of Chabahar, 5 km of Koch village , pool, 25º 46.084 N, 60º 54.968 E, 13.vii.2011 ( RMNH) . Paratypes: 5/0/0, same data as holotype ( RMNH)

Diagnosis. Idiosoma dorsally and ventrally sclerotized except for a narrow strip of papillose integument extending around coxal and genital field, and two median strips extending posteriorly from the posteromedial corner of Cx-IV to about two-third of the postgenital length; gonopore surrounded by a row of small setae and located on a raised high ridge.

Description. Male (holotype, in parentheses measurements of paratype specimens) — Idiosoma L/W 1280 (1040 – 1410) /1100 (950 – 1250); idiosoma dorsally and ventrally sclerotized except for a narrow strip of papillose integument extending around coxal and genital field, and two median strips extending posteriorly from the posteromedial corner of Cx-IV to about two-third of the postgenital length ( Fig. 4); coxal field: L 581, W 925; Cx-IV bearing one seta, posteromedial corner extending, with a cleaver-shaped extension of secondary sclerotization. Genital field L/W 252/216, heart-shaped, posteriorly extending beyond posterior margin of Cx-IV, anteriorly with a small indentation, gonopore surrounded by a row of small setae and located on a raised high ridge as shown in Figs. 5A – B; genital field hinged at anterior end but movable posteriorly, this movement leads to apparent differences in placement of the gonopore (see Figs. 5A – B); Ac small, but one larger Ac on each side located in the posterolateral part of the acetabular field. Gnathosoma stout, L 491, rostrum L 228, shorter than base, bent ventrally with a distinct kink ( Fig. 5C); chelicera L 572; palp ( Figs. 5D – E): total L 584; dL: P-1, 166; P-2, 138; P-3, 163; P-4, 81; P-5, 36; P-1 bearing one dorsodistal seta, P-2 strongly convex dorsally, ventral margin concave. Legs: dL of I-L-2-6 ( Fig. 5F): 144, 98, 113, 141, 168; dL of IV-L: 193, 175, 140, 244, 263, 242.

Etymology. The species is named for its occurrence in Sistan va Baluchestan Province.

Remarks. Due to the characteristic shape of the genital field, with its raised ridge surrounding the gonopore, and an extensive dorsal sclerotization, Hydrachna sistanica sp. nov. is most similar to H. mysorensis Cook, 1967 , a species described from a pond in Mysore State in India ( Cook 1967). Hydrachna mysorensis can be distinguished from the new species by the lack of ventral secondary sclerotization (see Cook 1967, Fig. 25). Furthermore, our species does not show the extreme humped condition of the dorsal side of P-2 which is typical for H. mysorensis .

Habitat. Standing water ( Fig. 8A).

Distribution. Iran; only known from the type locality in Sistan va Baluchestan Province.