Arrenurus ovatipetiolatus

Esen, Yunus, Erman, Orhan & Dilkaraoglu, Sibel, 2013, Contribution to the study of arrenuroid water mites (Acari: Hydrachnidia) from Turkey, Zootaxa 3666 (1), pp. 73-83 : 74

Arrenurus (s.str.) ovatipetiolatus Esen & Erman sp. nov.

Type material. Holotype male, Kahramanmaraş Province, Pazarcık, Lake Baġlama, 37°.16.52' N 37°.07.30' E, 555 m a.s.l., 07.viii.2012. Paratype: one female, same data as holotype; 1 male and 7 females, same location as holotype, 12.ix.2012.

Diagnosis. Male: Petiole long, ovally shaped, posteriorly rounded; posterior margin of ligulate process pointed, lateral margin of ligulate process irregularly undulating; associated setae of petiole not extending to posterior margin of petiole. Female: Medial margins of fourth coxal plates larger than medial margin of third coxal plates; medial distance between fourth coxal plates less than width of one genital valve; gonopore with sclerotized patches.

Description. Male: Idiosoma (in parentheses measurements of the paratype) 1463 (1360) long (including petiole) and 980 (900) wide. Anterior margin of idiosoma concave, dorsal shield incomplete, passing onto cauda, dorsal shield W 615 (572) (fig. 1A). Dorsal humps well developed (fig. 1B). Gonopore L 92 (84), genital plates extending to lateral body margin. Medial distance of fourth coxal plates smaller than width of gonopore (fig. 1C). Cauda distinct and well set off from anterior idiosoma, pygal lobes well developed. Petiole large, ovally shaped, widest in the middle, L 323 (290), maximum W 147 (140), rounded posteriorly, posterior margin of ligulate process pointed, lateral margin of ligulate process irregularly undulating. Associated setae of petiole shorter and slightly exceeding 50% length of petiole. Hyaline membrane relatively short, with a concave posterior margin (fig. 1D). Capitulum ventral L 160, chelicera L 182. Palp (fig. 1E) total L 373, dL of palp segments: P-1 40, P-2 94, P-3 68, P-4 100, P-5 71; P-2 medially with four setae. Swimming setae on leg segments; II-L-3: 4, II-L-4: 5, II-L-5: 6, III-L-3: 10, III-L-4: 11, III-L-5: 8, IV-L-3: 10, IV-L-4: 12, IV-L-5: 12. IV-L-4 with a spur. Dorsal L of I-L: 82-120- 141-216-178-222, IV-L-4-6: 432-160-207.

Female. Idiosoma L/W 1403 (1308)/1234 (1140), anterior margin of idiosoma straight, posterolateral corners distinct, dorsal shield complete, L/W 890 (825)/861 (800). Gonopore L/W 200 (188)/236 (230), genital valves with triangular chitinized patches, genital plates large, slightly bowed, laterally rounded, genital field W 700 (687). Medial distance of fourth coxal plates less than width of one genital valve (fig. 2A). Capitulum ventral L 167, chelicera L 190. Palp (fig. 2B) total L 401, dL of palp segments: P-1 42, P-2 94, P-3 68, P-4 100, P-5 71. P-2 medially with four setae. Swimming setae on leg segments; II-L-3: 4, II-L-4: 8, II-L-5: 6, III-L-3: 7, III-L-4: 10, III-L-5: 8, IV-L-3: 8, IV-L-4: 11, IV-L-5: 9. Dorsal L of I-L: 80-122-153-207-182-209, IV-L-4-6: 432-160-207.

Habitat. Stagnant waters covered with rushes and water lily.

Etymology. The species is named for its ovally shaped petiole.

Remarks. Due to the well developed pygal lobes, rounded posterior margin of petiole, concave anterior margin of body and incomplete dorsal shield, the new species is very similar A. ayyildizi Erman, 1993 and A. virens Neuman, 1880 . It can be distinguished from A. ayyildizi in the well developed dorsal humps, the posterior margin of the hyaline membrane wider, the associated setae of petiole not extending to posterior margin (in A. ayyildizi associated setae extending to posterior margin of petiole-see fig. 1F) and posterior margin of ligulate process pointed. Furthermore, differences are found in larger idiosoma size (in A. ayyildizi collected from Bingöl Province maximum L/W 1075/680) and preference habitat ( A. ayyildizi collected from streams). Arrenurus virens differs from the new species in the wider hyaline membrane posteriorly, the shorter petiole, the associated setae of petiole extending to posterior margin and the genital plates not extending to lateral margin of idiosoma.

The female of the new species is, due to the distinct posterolateral corners and shape of the genital field, similar to the female of A. ayyildizi . It differs from A. ayyildizi in the larger idiosoma size (in A. ayyildizi maximum L/W 1027/866) and genital valves with wider triangular chitinized patches.