Euconnus taiwanus Franz, 1985

Jałoszyński, Paweł, 2022, Taxonomy of ' Euconnus complex'. Part XXIV. Intermediate forms between Psomophus, Eupentarius and Euconnus s. str. in the East Palaearctic fauna unify problematic subgenera (Coleoptera, Staphylinidae, Scydmaeninae), Zootaxa 5194 (3), pp. 343-391 : 363-366

Euconnus taiwanus Franz

Euconnus taiwanus Franz, 1985a: 107 .

( Figs 68–80 , 112 )

Type material studied. Holotype (Taiwan): ♂, two labels: “Taiwan, 1400 m / Fenchihu, 10.4.77 / lg. Klapperich ” [white, handwritten], “ Euconnus / taiwanus m. / det. H.Franz ” [white, handwritten and printed], “ Holotypus ” [red, handwritten] ( NHMW).

Additional material examined (42 exx). Taiwan: ♂, Peinan Hsiang, Taitung Hsian, Chihpen Spa , 1- 5.04.2004, FIT, T. Tsuru leg. (cPJ) . Japan: Ishigaki-jima Is .: ♂, Banna-dake , 31.05- 01.06.2012, T. Lackner leg. (cPH) ; ♂, Omoto-dake , 22.03.1984, leg. S. Nomura ( NSMT) ; ♀, Omoto-dake , 09.04.1986, leg. S. Nomura ( NSMT) ; 2 ♂♂, 1 ♀, Omoto-dake , 11.06.2003, H. Mizushima leg. (cPJ) ; 4 ♂♂, Omoto-dake , 100 m, 15- 21.03.2004, FIT, leg. S. Nomura ( NSMT) ; 3 ♂♂, Ura-Banna , 100 m, 21- 23.03.2004, FIT, leg. S. Nomura ( NSMT) ; ♂, Omoto-dake , 18.06.2002, leg. T. Tsuru (cPJ) ; ♂, Shiramizu, 07.03.2002, Tullgren , leg. S. Nagashima (cPJ) ; ♀, Shiramizu , 30 m, 15.06.2003, leg. H. Mizushima (cPJ) ; ♂ Kabira env., 15.01.2017, leg. P. Jałoszyński (cPJ) ; 2 ♂♂, 1 ♀, Omoto-dake , 17.09.2003, leg. P. Jałoszyński ; ♀, Omoto-dake , 100 m, 02.01.2003, leg. P. Jałoszyński (cPJ) ; ♀, Nosoko-dake , 200 m, 12.06.2003, leg. H. Mizushima (cPJ) ; 2 ♀♀, Sokobaru Dam env., 17.01.2017, leg. P. Jałoszyński (cPJ) ; 3 ♂♂, “ by truck trap ”, 28.10.1996, leg. K. Takahashi ( NSMT); Iriomote-jima Is .: ♂, Gunkan-Iwa , 50 m, 17- 20.03.2004, FIT, S. Nomura leg. ( NSMT) ; ♀, Kanpiree-no-taki waterfall, 12.09.2003, leg. S. Arai (cPJ); ♂, Kanpiree , 13.04.1986, leg. S. Nomura ( NSMT) ; 3 ♂♂, Kanpiree , 80 m, 17- 20.03.2004, FIT, leg. S. Nomura ( NSMT) ; 1 ♂, 6 ♀♀, Komi , 09.06.2002, leg. T. Ishikawa (cPJ) ; ♀, Ôtomi-rindō , 19.06.2005, leg. T. Ishizaki (cPJ).

Diagnosis. Antennal club trimerous with antennomere 9 distinctly narrower than 10; males lacking secondary dimorphic features; aedeagus bottle-shaped, with short, transverse subtrapezoidal distal region; endophallus with transverse pair of symmetrical sclerotized structures in subapical region and elongate median subapical tubular component, usually showing darker inner granules.

Description. Body of male ( Figs 68 , 77 ) elongate, strongly convex; pigmentation moderately to darkly brown, appendages indistinctly lighter except for clearly lighter tarsi and maxillary palps; body covered with setae distinctly lighter than cuticle; BL 1.26–1.45 mm.

Head much narrower than pronotum, broadest at eyes, round, HL 0.29–0.33 mm, HW 0.23–0.26 mm; tempora in dorsal view about three times as long as eyes, behind eyes strongly and evenly convergent posterad, posterior margin of vertex strongly rounded and short, slightly bulging posterodorsad. Frons and vertex with unremarkable, fine punctures, glossy; setae sparse and suberect, tempora and posterior margin of vertex with dense thick bristles. Antennae short and compact, AnL 0.45–0.50 mm, scape and pedicel each distinctly elongate, antennomeres 3‒8 each slightly transverse (8 indistinctly so), 9‒11 gradually increasing in width and length, 9 and 10 each strongly transverse, 11 about as long as 9 and 10 combined, about 1.2 × as long as broad.

Pronotum subconical, broadest distinctly in front of base; PL 0.35–0.40 mm, PW 0.35–0.38 mm. Base with two pairs of pits, outer pits smaller than inner ones, sublateral carinae indistinct. Punctures and setae on disc similar to those on frons and vertex; sides of pronotum with dense thick bristles.

Elytra together oval, broadest clearly in anterior half; EL 0.63–0.75 mm, EW 0.50–0.55 mm, EI 1.25–1.45; humeral calli small but clearly marked and each mesally demarcated by small round basal elytral impression; elytral apices separately rounded. Punctures indistinct, superficial and unremarkable; setae sparse and slightly longer than those on pronotal disc, suberect.

Legs slender, protibiae unmodified, weakly and evenly curved, with mesal margins slightly sinuate.

Aedeagus ( Figs 69–72 : holotype, partly distorted; 73–76: non-type specimen from Taiwan; 78–80: non-type specimens from Japan) moderately stout, weakly sclerotized, AeL 0.23 mm; median lobe in ventral view in most specimens broadest in submedian region, but in some nearly parallel-sided, dorsal apical plate in ventral view short, transverse, subtrapezoidal; sclerotized ventral apical plate lacking, ventral subapical area membranous, endophallic structures symmetrical, with two lateral and one median elongate sclerites that in some specimens are partly everted ( Fig. 79 , indicated by arrowheads), in subapical region with pair of transverse sclerotized structures, and at middle with elongate, tubular component, usually containing inner areas of darker sclerotization visible as groups of granules. Parameres slender and short, not reaching apex of median lobe, distinctly broadened in subapical half, each with 2–4 long apical setae .

Female. Externally indistinguishable from male. BL 1.35–1.46 mm; HL 0.33–0.35 mm, HW 0.24–0.28 mm, AnL 0.43–0.50 mm; PL 0.38–0.40 mm, PW 0.35–0.38 mm; EL 0.65–0.73 mm, EW 0.53–0.58 mm, EI 1.18–1.40.

Distribution. Taiwan and Japan: southern Ryūkyū: Iriomote-jima and Ishigaki-jima islands ( Fig. 112 ).

Remarks. External differences between members of the Euconnus taiwanus group may be misleading, especially in species with males not showing any secondary dimorphic features, and examination of aedeagus is necessary to identify species.

Euconnus taiwanus is highly variable in terms of the body length and proportions of body parts, but the aedeagus, although it shows some variability, is distinctly different from that of any other member of this species group. As it occurs on Taiwan, Ishigaki-jima and Iriomote-jima, it can be expected to be found also on Yonaguni-jima, which is halfway between Iriomote and Taiwan and has suitable subtropical forests to maintain a rich Scydmaeninae fauna.

Figures

FIGURE 112. Distribution of Euconnus taiwanus Franz, and E. banana sp. n.

FIGURES 68‒76. Euconnus taiwanus Franz, holotype male (68‒72) and non-type specimen from Taiwan (73‒76). Dorsal habitus (68); aedeagus in ventral (69, 71, 73, 75) and lateral (70, 72, 74, 76) views.

FIGURES 77‒80. Euconnus taiwanus Franz, non-type males from Iriomote-jima. Dorsal habitus (77); aedeagus in ventral (78‒80) views (arrowheads indicate variable structures).