Osakatheta Maruyama, Klimaszewski & Gusarov

Maruyama, Munetoshi, Klimaszewski, Jan & Gusarov, Vladimir, 2008, Osakatheta yasukoae, a new intertidal genus and species of athetine rove beetles (Coleoptera, Staphylinidae, Aleocharinae) from Japan, Zootaxa 1683, pp. 39-50 : 40-41

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.

Figures

FIGURES 1 – 5. Osakatheta yasukoae, SEM photographs. 1 — habitus, dorsal view; 1 a—pronotum, dorsal view; 2 — facies, antero-dorsolateral view; 3 — head, antero-dorsal view; 4 — head, lateral view; 5 — head, ventro-lateral view.

FIGURES 6 – 10. Osakatheta yasukoae, mouthparts. 6 — labrum, dorsal view; 7 — epipharynx, adoral view; 8 — left mandible, dorsal view; 9 — left mandible, ventral view; 10 — right mandible, ventral view.

FIGURES 11 – 18. Osakatheta yasukoae, mouthparts. 11 — prementum; 12 — hypopharynx, adoral view; 1 — right maxilla, ventral view; 14 — right lacinia, ventral view; 15 — right lacinia, dorsal view; 16 — right galea, ventral view; 17 — right galea, dorsal view; 18 — mentum.

FIGURES 19 – 23. Osakatheta yasukoae, SEM photographs. 19 — pronotum, dorso-lateral view; 20 — prosternite, ventral view; 21 — meso- and metathorax, ventral view; 22 — elytra, dorso-lateral view; 23 — claws, right mid leg.

FIGURES 24 – 27. Osakatheta yasukoae, abdominal segment VIII. 24 — male tergite VIII; 25 — male sternite VIII; 26 — apex of male sternite VIII; 27 — apex of female sternite VIII.

FIGURES 28 – 35. Osakatheta yasukoae, male genitalia and spermatheca. 28 — median lobe of aedeagus, lateral view; 29 — median lobe of aedeagus, parameral view; 30 — everted internal sac, lateral view; 31 — everted internal sac, parameral view; 32 — paramere, lateral view; 33 — apical lobe of paramerite, lateral view; 34, 35 — spermatheca.

FIGURE 36. The type locality of Osakatheta yasukoae, a tidal flat at Nankô-yachôen, Ôsaka-fu, Japan. The beetles were found under the stones in the bottom of this photograph. Photographed by Rikio Matsumoto.

FIGURE 37. Known localities of Osakatheta yasukoae (black stars).