Paraneseuthia umisatu, Jałoszyński, 2023

Jałoszyński, Paweł, 2023, Two new species of Paraneseuthia Franz from Okinawa-jima (Coleoptera, Staphylinidae, Scydmaeninae), Zootaxa 5306 (4), pp. 490-496 : 494-495

Paraneseuthia umisatu sp. n.

( Figs 2 , 11–14 )

Type material. Holotype: JAPAN: ♂, two labels: “ OKINAWA-jima, Kunigami / Nishime-dake or Uka / Nov. 1, 2020 / leg. Norihide Tokushige ” [white, printed]; “ PARANESEUTHIA / umisatu m. / det. P. Jałoszyński, 2023 / HOLOTYPUS ” [red, printed] ( NSMT) . Paratypes (2 exx): 1 ♂, 1 ♀, “ JAPAN, OKINAWA Pref. / OKINAWAjima, 26 ii 2023 / Ohkuni-rindo, Okuma / 26°43'02.5''N / 128°11'56.7''E / 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 bottle-shaped, lacking projecting lateroapical lobes of median lobe, with long (twice as long as broad) median projection broader than 1/3 of width of aedeagus and with emarginate apex; apical sclerites strongly curved mesally and overlapping at middle; apices of parameres not reaching apex of median lobe; each paramere bearing one apical seta.

Description. BL 0.90–0.95 mm. Body of male ( Fig. 2 ) elongate and moderately convex, light brown, setae yellowish.

Head broadest at small but strongly convex and coarsely faceted eyes, HL 0.13 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 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 1.7× as long as broad.

Pronotum broadest near anterior third or slightly in front of middle (in Fig. 2 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 0.25–0.28 mm, PW 0.30–0.33 mm; pronotal base with pair of barely discernible 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 between middle and anterior third and relatively strongly narrowing posterad, evenly convex; EL 0.53–0.55 mm, EW 0.40 mm, EI 1.31–1.38; 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 convex, lacking median impression.

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

Aedeagus ( Figs 11–14 ) moderately slender, AeL 0.25 mm; median lobe in ventral view bottle-shaped, abruptly narrowed in distal half, lacking lateral subtriangular lobes, median apical region strongly elongate and with emarginate apex, in subapical area bearing pair of strongly curved pointed sclerites overlapping at middle; parameres short, with apices not reaching apex of median lobe, each with one apical seta.

Female. Externally similar to male, but protibiae barely discernibly recurved and lacking mesal expansion, compound eyes slightly smaller and less convex. BL 0.93 mm; HL 0.13 mm, HW 0.19 mm, AnL, 0.38 mm; PL 0.25 mm, PW 0.33 mm; EL 0.55 mm, EW 0.38 mm, EI 1.47.

Distribution. Okinawa Island, Japan.

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

Remarks. The division of the median lobe of the aedeagus into basal and distal regions of a subequal length, with the distal portion being much narrower than the basal capsule, is a unique feature among the Japanese species of Paraneseuthia and allows for a ready identification of P. umisatu . A more or less similar shape of the aedeagus can be found in P. luzonica Jałoszyński, 2019 ( Philippines), but this species has a strongly asymmetrical apex of the median lobe.

Two paratypes collected in Okuma were taken from sifted leaf litter and rotten wood (mainly tree trunks and thick branches with loose bark fallen to the ground) in a deciduous forest.

Figures

FIGURES 1–2. Dorsal habitus of males. Paraneseuthia uminzo sp. n. (1); P. umisatu sp. n. (2).

FIGURES 3–14. Aedeagus in ventral (3, 5, 7, 9, 11, 13) and lateral (4, 6, 8, 10, 12, 14) views of Paraneseuthia uminzo sp. n. (1–10; two specimens showing variation), and P. umisatu sp. n. (11–14).