Osakatheta Maruyama, Klimaszewski & Gusarov, gen. nov.

(Figs. 1–37)

Type species. Osakatheta yasukoae Maruyama, Klimaszewski & Gusarov, sp. nov.

Diagnosis. Osakatheta can be readily distinguished from most athetine genera by the erect setae covering the whole body.

Description. Body (Figs. 1–2) slender, broadened posteriorly; dorsal surface almost completely covered with dense and erect setae.

Head. Head capsule (Figs. 3–5) approximately circular, gently convex dorsally. Eyes (Figs. 3–5) oval in lateral view, somewhat prominent. Infraorbital carina absent (Fig. 5). Antennae (Figs. 1–5) 11-segmented, moniliform, almost as long as head and pronotum combined.

Mouthparts. Labrum (Fig. 6) strongly transverse (width/length ratio 2.1), rounded anteriorly; surface covered with some 45–50 pseudopores, except for posterior and lateral areas; apodeme roundly produced posteromedially, with lateral arm gently curved and its apex hidden under postero-medial projection of apodeme. Epipharynx as in Fig. 7. with long sensilla a, its medial sensory field with 11 pores and numerous minute sensory pseudopores; lateral row with 3–5 pores distributed between membranous wrinkles; 3 marginal setae slender, about 10 times as long as wide. Mandibles (Figs. 8–10) slightly asymmetric, mesal areas of dorsal surface covered with 30–40 pseudopores; prostheca obtuse at apex, its inner margin densely spinulate; left mandible (Figs. 8–9) generalised, without teeth; 3 small setae present laterally; right mandible (Fig. 10) with a small tooth at middle of inner margin, weakly serrate between tooth and apex; 3 small setae present laterally. Labium as in Figs. 11–12. Prementum (Fig. 11) with 2 real pores and 1 setal pore latero-mesally, 3–5 pseudopores between real pores, and 25–30 medial pseudopores; internal ridge (Fig. 11; indicated with arrow) very small, its length less than 1/6 that of prementum; apodeme (Fig. 11) with broom-like projections posteromedially, lateral lobe of apodeme (Fig. 11) gently curved, narrowed apically, pointed at apex. Ligula (Fig. 11) bilobed, with each lobe rounded and covered with minute pores apically; apical setae absent; lateral margin weakly sclerotized. Labial palpus (Figs. 11) with segment I long and twice as long as II; segment II notched from base to apex forming membranous zone, which bears one pore; segment III longer than II, slightly dilated apically, with 1 pore near apex, covered with spinulae at apex; setae α, β, and γ present. Hypopharynx (Fig. 12) generalised, without apical seta; medial sensory field simplified, with small ridges. Maxilla as in Figs. 13–17. Cardo (Fig. 13) generalised, almost elliptical in ventral view, with about 10 pseudopores. Stipes (Fig. 13) small, triangular, with 3 setae around base, and 5 or 6 pseudopores. Palpifer (Fig. 13) triangular in lateral view, with one large seta near apex, two small setae at middle and apex, and with some 5 pseudopores. Lacinia (Figs. 13–15) with some 6–8 pores around base and 2 setae laterally; apical inner margin with a row of 8 spines forming comb; surface around comb densely pubescent, and with a row of pores. Subgalea (Fig. 13) weakly sclerotized. Galea (Figs. 13, 16–17) broad, about 2.5 times as long as wide, slightly curved at middle, gently narrowed apically, with about 10 pores around middle of outer margin, densely pubescent and with pampas grass-like projection apically. Maxillary palpus as in Fig. 13; segment I very small, without setae; segment II gently curved, and much dilated apically, with some pores along apical margin; segment III largest, 1.5 times longer than 2nd, almost straight, widest at middle, moderately covered with pores except for basal and apical margins; 4th long, narrowed apically, with one pore around middle. Mentum (Fig. 18) trapeziform; anterior margin with a pair of projections, which bear seta u; posterior margin completely truncate; surface moderately covered with pseudopores except for antero-lateral area; seta w located antero-mesally.

Thorax. Pronotum (Figs. 1, 19) slightly transverse, angles widely rounded; microsetae directed anteriad in midline; in lateral portions of disk microsetae directed laterad (Type I, Benick & Lohse 1974). Hypomera (Fig. 19) visible laterally. Prosternum (Fig. 20) transversely sutured; densely covered with setae along anterior margin; posterior margin truncate. Scutellum generalised, its apex acutely pointed (Figs. 1, 22). Mesoventrite (Fig. 21) with mesoventral process moderate in length, 0.6 times as long as coxal cavities. Mesocoxae are moderately separated. Mesocoxal cavity not margined (Fig. 21). Hind wing reduced, and about as long as elytron.

Legs. Tarsal formula 4-5-5. Medial macroseta of mesotibia thin, slightly longer than tibial width. Empodium (Fig. 23) simple, without setae.

Abdomen. Segments III–VII (Fig. 1) with posterior margin almost straight; surface densely covered with erect setae. Tergites III–V with moderate basal impressions. Abdominal tergite VIII (Fig. 24) with basal suture curved laterally and continued apicad; sternite (Fig. 25) with basal suture reaching lateral sides. Tergites IX and X densely covered with setae.

Male characters. Sternite VIII (Figs. 25–26) with apical margin weakly sclerotized forming transparent zone, lacking minute pubescence and with apical sensory setae which are 1.5 times as long as in female. Aedeagus: median lobe (Figs. 28–29) with basal capsule bulbous; distal crests fused on their sides, projecting; copulatory piece (Figs. 30, 31) bent in lateral view; paramere (Figs. 32–33) with condylite almost straight; hinge zone obscure.

Female characters. Sternite VIII (Fig. 27) with apical margin fully sclerotized, with minute pubescence and apical sensory setae shorter than in male. Spermatheca (Figs. 34–35) with capsule much shorter than elongate stem.

Etymology. Osakatheta is a combination of “Ôsaka”, the type locality of the type species, and “ Atheta ”, the type genus of the tribe Athetini. Gender feminine.

Distribution. Japan: Honshû. So far known from Honshû, Japan. It is probably more broadly distributed in the other regions of East Asia.