Euconnus (s. str.) urauchianus, Jałoszyński, 2022

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 : 360-363

Euconnus (s. str.) urauchianus sp. n.

( Figs 59–63 , 111 )

Type material studied. Holotype ( Japan: Okinawa Prefecture: Iriomote-jima Is.): ♂, two labels: “JAPAN, OKINAWA Pref. / Iriomote-jima, Urauchi / near Mâre-gawa river / 11-13.ix.2003 / Koji& Shiho Arai leg.” [white, printed], “ EUCONNUS s. str. / urauchianus m. / P. Jałoszyński, ’22 / HOLOTYPUS ” [red, printed] ( NSMT) . Paratypes (3 exx): ♂, same data as for holotype; 2 ♂♂, “JAPAN, OKINAWA Pref. / Iriomote-jima, Komi / 9.vi.2002 / T. Ishikawa leg.” . Paratypes with yellow “ PARATYPUS ” labels similar to that with holotype, deposited in NSMT and cPJ.

Diagnosis. Antennal club with antennomere 8 only slightly larger than 7 but much smaller than 9; head round, with vertex not bulging posterodorsad; pronotum subconical and broadest at base, with one pair of distinct antebasal pits and additional median pit (in one studied specimen, median pit situated in short transverse groove), sublateral carinae indistinct; head and protibiae in males unmodified; aedeagus weakly sclerotized, in ventral view with strongly elongate dorsal apical plate, its apex blunt, subtriangular, dorsal plate in lateral view bent distodorsad at base, with distal region straight, ventral apical plate in ventral view with bifurcate apex, additional sublateral projections between ventral and dorsal plate subtriangular, endophallic structures symmetrical but poorly defined (i.e., lacking clearly delimited sclerites).

Description. Body of male ( Fig. 59 ) elongate, flattened; pigmentation moderately light brown, appendages indistinctly lighter; body covered with setae distinctly lighter than cuticle; BL 0.93–1.05 mm.

Head smaller than pronotum, broadest at eyes, round, HL 0.18–0.20 mm, HW 0.18–0.20 mm; tempora in dorsal view about twice as long as eyes, behind eyes strongly and evenly convergent posterad, posterior margin of vertex strongly rounded, not 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, but with loosely assembled clubs, AnL 0.38 mm, scape and pedicel each only slightly elongate, antennomeres 3‒7 each transverse, 8 nearly as long as broad and only slightly enlarged in relation to 7, 9‒10 gradually broadening, both strongly transverse, 11 slightly shorter than 9 and 10 combined, about as long as broad.

Pronotum subconical, broadest at base; PL 0.23–0.25 mm, PW 0.21–0.24 mm. Base with one pair of distinct antebasal pits, and additionally with median pit that is slightly larger than lateral ones (in one paratype median pit situated in short transverse groove not reaching lateral pits), 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 slightly in front of middle; EL 0.53–0.60 mm, EW 0.35–0.38 mm, EI 1.50–1.60; humeral calli small but clearly marked and each mesally demarcated by round basal elytral impression; elytral apices separately rounded. Punctures indistinct, superficial and unremarkable; setae sparse and not longer than those on pronotal disc, but slightly thicker, suberect.

Legs slender, protibiae unmodified, weakly and evenly curved, with mesal margin arcuate, concave.

Aedeagus ( Figs 59–63 ) stout, weakly sclerotized, AeL 0.18 mm; median lobe in ventral view broadest in submedian region, dorsal apical plate in ventral view strongly elongate and with subtriangular, blunt apex, in lateral view bent distodorsally and with distal region straight, ventral apical plate broader than dorsal one and with bifurcate apex, pair of distally divergent sublateral projections is situated between plates, endophallus lacking strongly sclerotized components, symmetrical. Parameres broad and relatively long, almost reaching apex of median lobe, each with 2 long apical and two long subapical setae.

Female. Unknown.

Distribution. Japan, southern Ryūkyū: Iriomote-jima Is. ( Fig. 111 ).

Etymology. The adjective urauchianus refers to the Urauchi-gawa River, one of two localities where the type series comes from.

Remarks. This is another small-bodied species similar to several undescribed Euconnus spp. so far known only from females and must be identified by aedeagal structures. The uniquely bifurcate ventral apical plate, the elongate dorsal apical plate and the general shape of the median lobe allow for unambiguous determination.

Figures

FIGURE 111. Distribution of Euconnus pseudotrimerus sp. n., and E. urauchianus sp. n.

FIGURES 59‒63. Euconnus urauchianus sp. n., male. Dorsal habitus (59); aedeagus in ventral (60, 62) and lateral (61, 63) views.