Euconnus cryptoiriomotensis, 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 : 370-372

Euconnus cryptoiriomotensis sp. n.

( Figs 92–96 , 114 )

Type material studied. Holotype ( Japan : Okinawa Prefecture: Iriomote-jima Is.): ♂, two labels: “ JAPAN, OKINAWA Pref. / IRIOMOTE-JIMA, 8 km NW / Ôhara, jungle, 13 I 2017 / leg. P. JAŁOSZYŃSKI” [white, printed], “ EUCONNUS s. str. / cryptoiriomotensis m. / P. Jałoszyński, ’22 / HOLOTYPUS ” [red, printed] ( NSMT).

Diagnosis. Antennal club trimerous with antennomere 9 distinctly narrower than 10; males lacking secondary sexual characters; aedeagus conspicuously stout, with emarginate dorsal apical plate and with ventral apical plate distinctly elongate, at base about as broad as in subapical region, with distinct constriction.

Description. Body of male ( Fig. 92 ) elongate, strongly convex; pigmentation dark brown, appendages indistinctly lighter except for clearly lighter tarsi and maxillary palps; body covered with setae distinctly lighter than cuticle; BL 1.35 mm.

Head much narrower than pronotum, broadest at eyes, HL 0.33 mm, HW 0.25 mm; tempora in dorsal view about 3 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 mm, scape and pedicel each distinctly elongate, antennomeres 3‒7 each slightly transverse, 8 as long as broad, 9‒11 gradually increasing in width and length, 9 and 10 each strongly transverse, 11 as long as 9 and 10 combined, about as long as broad.

Pronotum subconical, broadest distinctly behind middle; PL 0.35 mm, PW 0.33 mm. Base with two pairs of pits, outer pits barely noticeable, small and shallow, inner pair connected by barely noticeable faint transverse groove. Punctures and setae on disc similar to those on frons and vertex; sides of pronotum with dense thick bristles.

Elytra together oval, broadest distinctly in front of middle; EL 0.68 mm, EW 0.50 mm, EI 1.35; humeral calli small, elongate, each mesally demarcated by short elongate impression; elytral apices separately rounded. Punctures indistinct, superficial and unremarkable; setae sparse and distinctly longer than those on pronotal disc, suberect.

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

Aedeagus ( Figs 93–96 ) stout, moderately strongly sclerotized, AeL 0.18 mm; median lobe in ventral view broadest in submedian region, dorsal apical plate in ventral view emarginate at middle, ventral apical plate elongate, at base about as broad as in subapical region, broadly constricted and with blunt subtriangular apex; endophallic structures symmetrical, lightly sclerotized and poorly delimited. Parameres relatively broad and long, almost reaching apex of median lobe, each with 4‒5 long apical and subapical setae, and additionally with 3 tiny setae far from apex, on lateral surface.

Female. Unknown or indistinguishable from similar species (see Remarks).

Distribution. Japan: southern Ryūkyū: Iriomote-jima Is. ( Fig. 114 ).

Etymology. The adjective cryptoiriomotensis refers to the cryptic habitus and the occurrence on Iriomotejima.

Remarks. The only known male of this species is externally indistinguishable from the sympatric E. bibaculatus and allopatric E. oitaensis . The aedeagus is strikingly different from that of E. bibaculatus , but similar to that of E. oitaensis . Euconnus cryptoiriomotensis occurs on Iriomote-jima, and E. oitaensis on eastern Kyūshū, ~ 1200 km NE of Iriomote. The ventral apical plate in E. cryptoiriomotensis is elongate and at base nearly as broad as in subapical region, with distinct constriction, whereas in E. oitaensis the ventral apical plate is about as long as broad, clearly broadest at base and strongly narrowing up to the submedian region. I treat these differences as species-specific. However, additional specimens collected from islands between the known sites where these species occur may verify this hypothesis, if a morphocline in male genital structures is found.

Figures

FIGURE 114. Distribution of Euconnus cryptoiriomotensis sp. n.

FIGURES 92‒96. Euconnus cryptoiriomotensis sp. n., male. Dorsal habitus (92); aedeagus in ventral (93, 95) and lateral (94, 96) views.