Nogunius microtaiwanensis, Jałoszyński, 2024

Jałoszyński, Paweł, 2024, Two new species of Nogunius Jałoszyński in Taiwan (Coleoptera: Staphylinidae: Scydmaeninae), Zootaxa 5437 (3), pp. 441-447 : 442-444

Nogunius microtaiwanensis sp. n.

( Figs 1, 3 , 5–8 , 13 )

Type material. Holotype: TAIWAN (Taitung Co.): ♁, three labels: “ 08.IV.2007 leg. S. Vit / Rd.no.20, km174 / after Litao , Taitung Co. / TAIWAN merid. / mount. frst. litter / (alt± 1300 m.)” [white, printed], “ Coll. S. Vit / MHNG - 2021” [white, printed], “ NOGUNIUS / microtaiwanensis m. / P. Jałoszyński, 2024 / HOLOTYPUS” [red, printed] ( MHNG) . Paratypes (5 exx.): 1 ♁, same data as for holotype; 1 ♁, “ 08.IV.2007 leg. S. Vit / Rd.no.20, km188 / bfr. Wulu, Taitung Co. / TAIWAN merid. / mount. frst. litter / (alt± 750 m.)” [white, printed]; 1 ♁, “ 08. IV.2007 leg. S. Vit / Rd.no.20, km202 / after Chulai , Taitung Co. / TAIWAN merid. / plane frst. litter / (alt± 200 m.)” [white, printed]; 2 ♁♁, “ 12.IV.2007 leg. S. Vit / Rd.no.11, W-Tulan, / envs. Frst. Moonlight-Inn / Taitung Co. TAIWAN merid. / frst. litter / (alt± 200 m.)” [white, printed]. Paratypes in MHNG and cPJ .

Diagnosis. Eyes in male large and strongly convex but in dorsal view much shorter than tempora; aedeagus in ventral view about three times as long as broad, with apical margin broadly subtriangular and obtuse-angled.

Description. Body of male ( Fig. 1 ) moderately slender, strongly convex, light brown with appendages indistinctly lighter than head, thorax and elytra, setae yellowish-brown; BL 0.63–0.68 mm.

Head ( Fig. 3 ) broadest at eyes, HL 0.13 mm, HW 0.13–0.15 mm; tempora in dorsal view much longer than eyes; vertex and frons confluent, together weakly convex; each eye large, strongly convex, in lateral view bean-shaped, with distinct posteromedian emargination. Punctures on vertex fine, inconspicuous; setae short, sparse and suberect; tempora and posterior margin of vertex densely covered with thick and long bristles. Antennae slender, AnL 0.28– 0.30 mm, antennomeres 1 and 2 each strongly elongate, 3–6 each about as long as broad, 7 and 8 indistinctly transverse, 9 distinctly larger than 8 and slightly transverse, 10 much longer and especially broader than 9, strongly transverse, 11 indistinctly narrower and slightly longer than 10, about as long as broad.

Pronotum subconical with rounded sides, broadest shortly in front of base; PL 0.18–0.20 mm, PW 0.15–0.16 mm. Anterior and posterior margins weakly convex, base with two pairs of small pits, of which inner pair is distinct, and outer barely discernible. Punctures on pronotal disc fine, inconspicuous; setae sparse, short, suberect; sides, especially posteriorly, with sparse, thick bristles.

Elytra together oval, broadest indistinctly in front of middle; EL 0.33–0.35 mm, EW 0.26–0.28 mm, EI 1.23– 1.29; humeral calli weakly elevated, basal impressions large, deep, nearly circular; apices separately rounded. Punctures inconspicuous; setae similar to those on pronotum, suberect.

Legs moderately long and slender, unmodified.

Hind wings long, functional.

Aedeagus ( Figs 5–8 ) elongate, in ventral view about three times as long as broad; AeL 0.10 mm; median lobe in ventral view broadest near proximal third, with weakly convex sides gradually and weakly converging toward apex, apical margin broadly subtriangular and obtuse-angled, blunt; endophallus in ventral view with a pair of large lateral elongate and darkly sclerotized structures, in lateral view approximately T- or Y-shaped; parameres slender, in lateral view weakly curved, each with one long apical and one long subapical seta.

Female. Unknown.

Distribution. South-eastern Taiwan ( Fig. 13 ).

Etymology. The adjective microtaiwanensis refers to the minute body and the geographical distribution.

Remarks. Nogunius microtaiwanensis has the smallest adults of all known species, not reaching 0.7 mm. The head in dorsal view resembles mostly that of N. infuscus sp. n. described below, and among the Japanese congeners N. sagaensis and N. aogashimanus . Nogunius sokani has clearly larger eyes, and N. kerri and N. fukuuzanus have the eyes much smaller. Nogunius sagaensis and N. aogashimanus have the apical regions of the median lobe strongly curved ventrad (visible in lateral view; Fig. 13 ) and a clearly different shape of the apical margin of aedeagus in ventral view. Nogunius microtaiwanensis clearly differs from N. infuscus in a lightly pigmented body (dark elytra in N. infuscus ) and the blunt, obtuse-angled aedeagal apex in ventral view (pointed and sharp-angled in N. infuscus ). Measurements that can facilitate identifications are compiled in Table 1 .

Figures

FIGURE 13. Distribution of nominal Nogunius species, showing aedeagi for comparative purposes.

FIGURES 1–4. Nogunius microtaiwanensis sp. n. (1, 3) and N. infuscus (2, 4). Dorsal habitus of male (1, 2), and head in anterodorsal view (3, 4).

FIGURES 5–12. Nogunius microtaiwanensis sp. n. (5–8) and N. infuscus (9–12). Aedeagus in ventral (5, 7, 9, 11) and lateral (6, 8, 10, 12) views.