Gymnostigmaeus, Ehara & Ueckermann, 2006

Ehara, Shôzô & Ueckermann, E. A., 2006, A new genus of Stigmaeidae (Acari: Prostigmata) from Okinawa Island, Zootaxa 1160, pp. 29-36 : 30

Genus Gymnostigmaeus n. gen.

Type species: Gymnostigmaeus akaminei n. sp., by monotypy.

Diagnosis

Idiosoma elongate­oval, with 12 pairs of dorsal setae (3 pairs on prodorsum, 9 pairs on opisthosoma); neither shields nor platelets present on dorsum and venter which are entirely striate. Postocular bodies absent. Tibiae III and IV without solenidia. Empodia arising distally on a swollen arolium.

The genus Gymnostigmaeus n. gen. is similar to Parastigmaeus Kuznetzov, Pilonychiopus Meyer, Summersiella González­Rodríguez and Neilstigmaeus Gerson & Meyer in having a swollen arolium on the leg tarsi ( González­Rodríguez, 1967; Meyer, 1969; Kuznetzov,1984; Ueckermann & Meyer, 1987; Gerson & Meyer, 1995; Khanjani & Ueckermann, 2002). However, the new genus is distinct in lacking shields and platelets on the dorsum and venter. Parastigmaeus differs from the new genus in the presence of a suranal shield and tibiae III–IV bearing solenidia. Pilonychiopus further differs from Gymnostigmaeus n. gen. in having a suranal shield present, tarsi without claws and tibiae III–IV with solenidia. Summersiella differs in that the dorsum has 13 pairs of setae, dorsum with prodorsal and suranal shields, palptarsus bent, empodium situated at base of arolium and tibiae III–IV with solenidia. Neilstigmaeus differs from the new genus in having 3 dorsal shields, leg tarsi without claws and tibiae III–IV with solenidia. It is also closely related to Erynglpusopsis Tseng in general appearance, the absence of postocular bodies and solenidia on tibiae III–IV. According to Tseng’s (1982) key and figures, Gymnostigmaeus n. gen. differs from Erynglpusopsis in the absence of dorsal and ventral shields and platelets, presence of an arolium on the leg tarsi, having 12 pairs of dorsal setae and absence of a distinct suture between prodorsum and opisthosoma.

Etymology

The generic name Gymnostigmaeus is a combination of the Greek word “ gymnos ” (bare or naked) and the generic name Stigmaeus . It is masculine in gender, and refers to the absence of dorsal and ventral shields and platelets.