Paraneseuthia uminzo sp. n.

(Figs 1, 3–10)

Type material. Holotype: JAPAN: ♂, two labels: “ OKINAWA-jima, Nishihara-chô, / near parking lot of Nishihara / Undôkôen, 28 iii 2020 / 26°13‘51.4“N 127°45‘30.0“E / leg. Norihide Tokushige ” [white, printed]; “ PARANESEUTHIA / uminzo m. / det. P. Jałoszyński, 2023 / HOLOTYPUS ” [red, printed] (NSMT). Paratypes (7 exx): 1 ♀, “ OKINAWA-jima, Nishihara- chô, / Nishihara Park / Oct. 11, 2020 / leg. Norihide Tokushige ”; 3 ♀♀, “JAPAN, OKINAWA Island / Motobu Penins., near / Nakijin Castle, ~ 50 m, / humid forest, 14.02.2019 / leg. P. JAŁOSZYŃSKI”; 1 ♂ 2 ♀♀, “JAPAN, OKINAWA Pref. / OKINAWA-jima, N / Nakijin Castle env., / forest, sifted rotten wood / 20 II 2020 / leg. P. JAŁOSZYŃSKI” (paratypes in cPJ).

Diagnosis. Body small (BL <1 mm); protibia in male with angulate mesal expansion between proximal third and middle; aedeagus in ventral view with strongly developed lateroapical subtriangular lobes of median lobe and short (broader than long) median projection as broad as about 1/3 of width of aedeagus and bearing pair of curved and projecting laterally elongate sclerites pointed at apices; apices of parameres reaching apex of median lobe, each paramere bearing one subapical and one apical seta.

Description. BL 0.86–0.88 mm. Body of male (Fig. 1) elongate and moderately convex, moderately dark brown, setae yellowish.

Head broadest at large, strongly convex and coarsely faceted eyes, HL 0.11 mm, HW 0.20 mm; vertex and frons confluent and evenly, weakly convex; supraantennal tubercles small but distinct. Punctures on head dorsum inconspicuous; setae short, sparse and suberect. Antennae slender, with indistinctly delimited trimerous club, AnL 0.40–0.41 mm, antennomeres I–II elongate, III–VIII each about as long as broad, IX and X indistinctly transverse, XI broader than X, about as long as IX–X together, about 1.8× as long as broad.

Pronotum broadest near anterior third (in Fig. 1 slightly tilted anteroventrally, so the shape is not shown in strictly dorsal view), with anterior and lateral margins rounded and posterior margin nearly straight, lateral margins weakly narrowing toward obtuse-angled and blunt posterior corners; PL 0.23–0.24 mm, PW 0.28–0.30 mm; pronotal base with pair of small but distinct inner pits not connected by groove, and with outer pair of L-shaped impressions near each hind corner (with the bottom line of ‘L’ directed mesally). Punctures on pronotal disc fine and inconspicuous; setae moderately long, sparse and suberect.

Elytra oval, broadest near anterior third and relatively strongly narrowing posterad, evenly convex; EL 0.53 mm, EW 0.38 mm, EI 1.40; humeral calli distinct but small, basal impressions indistinct; apices separately rounded. Punctures on elytra distinct but small and diffuse, dense, in anteromedian portion of elytra separated by spaces equal to or slightly smaller than diameters of punctures, posteriorly punctures becoming smaller and shallower to disappear near elytral apices; setae long, moderately dense and suberect. Hind wings well developed.

Metaventrite with large, slightly elongate but shallow and diffuse impression in posterior half.

Legs moderately long and slender; protibiae distinctly bent near proximal third, with mesal angulate expansion.

Aedeagus (Figs 3–10) stout, AeL 0.23 mm; median lobe in ventral view broadest in subapical region, with large subtriangular lateral subapical lobes flanking short and broad median projection that bears lateral pair of elongate, curved and pointed sclerites directed laterally (in Figs 3 and 5 right sclerite is broken off); parameres slender, slightly broadened in subapical regions, parameral apices reaching apex of median lobe and each paramere bearing one subapical and one apical seta. Variation found in two studied males (externally indistinguishable) is shown in Figs 3–6 and 7–10; it can be attributed to movable apical projections that seem to be slightly displaced in the first illustrated specimen.

Female. Externally similar to male, but protibiae barely discernibly recurved and lacking mesal expansion, metaventrite not impressed, and antennae indistinctly shorter in relation to body length (AnL/BL 0.46–0.48 in males vs. 0.34–0.44 in females). BL 0.80–0.89 mm; HL 0.10–0.11 mm, HW 0.19–0.20 mm, AnL, 0.30–0.35 mm; PL 0.23–0.25 mm, PW 0.29–0.30 mm; EL 0.48–0.53 mm, EW 0.35–0.38 mm, EI 0.34–0.44.

Distribution. Okinawa Island, Japan.

Etymology. The noun in apposition uminzo comes from the Uchinaaguchi language of Okinawa-jima and means a female sweetheart.

Remarks. Among world species of Paraneseuthia, only P. zanetae Jałoszyński, 2019 (the first known Okinawan species) and P. holzneri (Franz, 1976) (Honshu) have the aedeagi with similarly stout median lobes as that in P. uminzo. However, the aedeagus of P. zanetae lacks any traces of the conspicuous lateral subtriangular lobes developed in the subapical region in P. uminzo, and has much longer and strongly asymmetrical pair of apical sclerites. The lateral lobes, although shorter, occur in the aedeagus of P. holzneri, but the median apical region between the lobes is developed as an elongate projection broadening distally and with a deep round median apical emargination, while the median projection in P. uminzo is conspicuously short, distinctly transverse. The geographically closest species, P. ishigakiana Jałoszyński, 2018 known to occur on the subtropical Ryukyuan Island of Ishigaki-jima, ~ 380 km SW of WS coast of Okinawa-jima, also lacking the subtriangular lateral lobes of the aedeagus, has enormously enlarged and strongly curved pair of apical sclerites, and conspicuously broadened parameres.

All six paratypes collected near Nakijin Castle come from deciduous forest through which the Hanta-michi (“road over a cliff”) passes. Three specimens taken in 2019 were collected by sifting partly dried and partly moist rotten wood in a small tree hollow, ~ 1.5 m above the ground, with no other accompanying beetles. The hollow was inside a proximal end of a broken lateral branch, with a diameter ~ 10 cm and depth ~ 20 cm, and the bottom of the hollow not reaching the main trunk. Also three specimens were collected a year later near the same site, by sifting leaf litter and small pieces of fallen branches around 10 cm in diameter, so rotten that it was possible to crush them by hand.