Euconnus (s. str.) pseudotrimerus, 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 : 359

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

( Figs 54–58 , 111 )

Type material studied. Holotype ( Japan : Kanagawa Prefecture): ♂, two labels: “ JAPAN, Kanagawa Pref. / Sagamiko env., ca. 300 m / 19 IV 2003 / leg. P. Jałoszyński ” [white, printed], “ EUCONNUS s. str. / pseudotrimerus m. / P. Jałoszyński, ’22 / HOLOTYPUS ” [red, printed] ( NSMT).

Diagnosis. Antennal club with antennomere 8 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 connected by also distinct transverse groove, and with pair of distinct sublateral carinae; head and protibiae in males unmodified; aedeagus weakly sclerotized, in ventral view with broadly rounded apical margin of dorsal apical plate, which in lateral view is strongly bent dorsad; ventral apical plate narrower than dorsal one and also broadly rounded at apex, between plates pair of distally divergent sublateral projections can be seen.

Description. Body of male ( Fig. 54 ) elongate, flattened; pigmentation moderately light brown, appendages distinctly lighter; body covered with setae distinctly lighter than cuticle; BL 0.93 mm.

Head smaller than pronotum, broadest at eyes, round, HL 0.18 mm, HW 0.18 mm; tempora in dorsal view about 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 club, AnL 0.38 mm, scape and pedicel each elongate, antennomeres 3‒6 each transverse, 7 as long as broad, 8‒10 gradually broadening, 8 slightly transverse, 9 and 10 each strongly transverse, 11 slightly shorter than 9 and 10 combined, about as long as broad.

Pronotum subconical, broadest at base; PL 0.23 mm, PW 0.23 mm. Base with one pair of distinct antebasal pits connected by distinct transverse impression, and with distinct sublateral carinae. 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 front of middle; EL 0.53 mm, EW 0.35 mm, EI 1.50; 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 margins sinuate.

Aedeagus ( Figs 55–58 ) stout, weakly sclerotized, AeL 0.14 mm; median lobe in ventral view parallel-sided in median region, dorsal apical plate in ventral view broadly rounded and in lateral view abruptly, strongly bent dorsad, ventral apical plate narrower than dorsal one and with broadly rounded apex; pair of distally divergent sublateral projections is situated between plates; endophallus lacking strongly sclerotized components, symmetrical. Parameres broad and short, not reaching apex of median lobe, each with 2 long apical and several tiny subapical setae.

Female. Unknown.

Distribution. Japan, Kantō region: Kanagawa Prefecture ( Fig. 111 ).

Etymology. The adjective pseudotrimerus refers to the structure of the antennal club.

Remarks. This small-bodied species is similar to several undescribed Euconnus species that occur in various regions of Japan, and so far known only from females. Consequently, the aedeagus must be examined to identify E. pseudotrimerus . The dorsal apical plate broadly rounded in ventral view and sharply bent dorsad in lateral view, the pair of subapical sublateral projections between the dorsal and ventral apical plates and the structure of the endophallus are all unique for this species.

Figures

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

FIGURES 54‒58. Euconnus pseudotrimerus sp. n., male. Dorsal habitus (54); aedeagus in ventral (55, 57) and lateral (56, 58) views.