Rutaraphes taiwanicus, Jałoszyński, 2020

Jałoszyński, Paweł, 2020, A new species of Rutaraphes Jałoszyński in Taiwan (Coleoptera, Staphylinidae Scydmaeninae), Zootaxa 4890 (3), pp. 446-450 : 447-450

Rutaraphes taiwanicus sp. n.

( Figs 1–7 )

Material studied. Holotype: ♁ ( TAIWAN): two labels: “ TAIWAN, Yilan, / Taipingshan forest , / 24.4964 121.5250, / 2216m, 27.viii.2013, sift / TW13, V.Grebennikov” [white, handwritten], “ RUTARAPHES / taiwanicus m. / P. JAŁOSZYŃSKI, 2020 / HOLOTYPUS ” [red, printed] ( NMNS).

Diagnosis. Vertex in male with pair of oval, narrowly separated impressions densely filled with short setae; pro- notum with two pairs of distinct antebasal pits, inner pair narrowly separated by tiny horn-like projection; aedeagus in lateral view lacking dorsal projection just above basal orifice, in ventral view conspicuously asymmetrical, al-most C-shaped.

Description. Body of male ( Fig. 1 ) slender, moderately convex, BL 1.23 mm; pigmentation light brown with appendages indistinctly lighter than body, setae distinctly lighter than cuticle.

Head ( Fig. 2 ) flattened and subtriangular with long clypeus distinctly broadening anterad, broadest at eyes, HL 0.20 mm, HW 0.20 mm; tempora in dorsal view much shorter then eyes, strongly convergent posteriorly, vertex with well-marked posterior margin and pair of large, oval impressions filled densely with short setae, so that cuticle within impressions is not visible, impressions narrowly separated at middle by tiny horn-like tubercle, in lateral view distinctly projecting dorsoposterad; frons in front of impressions flattened; supraantennal tubercles distinctly elevated; eyes large, strongly convex, finely faceted, oval, lacking posterior emargination. Punctures on frons and vertex inconspicuous, very fine; setae unevenly distributed, mainly along posterior margin of vertex, laterad each vertexal impression and between supraantennal tubercles, short, sparse and suberect. Antennae slender, with indis-tinctly demarcated trimerous club, strikingly short, slightly shorter than head and pronotum combined, AnL 0.43 mm; scape and pedicel each strongly elongate, antennomere 3 indistinctly transverse, 4 about as long as broad, 5 indistinctly elongate, 6 about as long as broad, 7 barely noticeably transverse, 8–10 each distinctly transverse, 11 indistinctly shorter than 9 and 10 combined, about 1.5 × as long as broad.

Pronotum broadest slightly anterior to middle but weakly narrowing posterad, PL 0.30 mm, PW 0.28 mm; anterior margin and sides in anterior half rounded, sides in posterior half nearly straight and with distinct, sharply marked lateral carinae in posterior third; posterior corners nearly right; posterior margin straight; base with two pairs of distinct, sharply marked pits: outer pits large and elongate, adjacent to lateral pronotal carinae, inner pits circular and separated only by narrow, slightly raised longitudinal carina. Punctures on disc fine, inconspicuous; setae dense, short, suberect.

Elytra together oval, broadest slightly in front of middle, EL 0.73 mm, EW 0.48 mm, EI 1.53; humeral calli distinctly elevated and elongate; basal elytral pits situated in deep but small circular basal impressions; elytral api-ces separately rounded. Punctures more distinct than those on pronotum and dense, but superficial and with diffuse margins; setae similar to those on pronotum but indistinctly sparser.

Hind wings well developed, functional.

Legs moderately long and slender, unmodified.

Aedeagus ( Figs 3–6 ) strikingly asymmetrical, so that it is difficult to define ventral and dorsal sides without knowing the orientation inside abdomen; AeL 0.25 mm; median lobe in ventral view (= abparameral view) strongly curved, nearly C-shaped, with diaphragm subapical and oblique in relation to the long axis of aedeagus, apical pro-jections shifted to the right side, asymmetrical and complicated, composed of twisted plates; dorsal wall of median lobe above basal orifice with narrow median longitudinal ‘fin’; basal orifice surrounded by thick collar.

Female. Unknown.

Distribution ( Fig. 7 ). Northern Taiwan.

Etymology. After the island of Taiwan.

Remarks. Rutaraphes taiwanicus differs from R. shikokuensis in male head modifications, with two distinct oval setal patches instead of a single median semicircular group of dense short setae ( Fig. 7 ). These two species dif-fer also clearly in the shape of the pronotum (more elongate and with distinctly sinuate sides in posterior half in R. shikokuensis ), inner antebasal pronotal pits in R. shikokuensis separated by a round tubercle vs. narrow carina in R. taiwanicus , and the form of the aedeagus. In R. taiwanicus , the median lobe is even more asymmetrical than that in R. shikokuensis , strongly curved and with twisted, complicated apical projections (in R. shikokuensis the aedeagus in ventral view is weakly asymmetrical, and apical projections are entirely hidden behind median lobe, not project-ing distad beyond it, as in R. taiwanicus ).

Figures

FIGURE 7. Distribution and key characters (head of male and aedeagus) of Rutaraphes species.

FIGURES 1–2. Rutaraphes taiwanicus sp. n. Dorsal habitus (1) and head of male holotype (2).

FIGURES 3–6. Rutaraphes taiwanicus sp. n. Aedeagus in ventral (3), left lateral (4), dorsal (5), and right lateral (6) views.