Microscydmus (Microscydmus) yusuharanus, Jałoszyński, 2019

Jałoszyński, Paweł, 2019, Unexpected diversity of Microscydmus Saulcy & Croissandeau in Japan (Coleoptera: Staphylinidae: Scydmaeninae), Zootaxa 4679 (3), pp. 539-552 : 547-549

Microscydmus (Microscydmus) yusuharanus sp. n.

( Figs 7 , 15 , 23 , 31 )

Type material. Holotype: JAPAN (Kôchi Pref.): ♂, two labels: "[ Kôchi : JAPAN] / Kami-oriwatari / Yusuharacho / 14. vi. 1997 / M. Sakai (½ * {= Japanese kuchiki, rotten wood})" [white, printed]; " MICROSCYDMUS (s. str.) / yusuharanus m. / P. Jałoszyński, 2019 / HOLOTYPUS " [red, printed] ( EUMJ).

Diagnosis. Body length ~ 0.75 mm; frons and vertex with fine and shallow but distinct, dense punctures; bristles on tempora and vertex well-visible; protibia not thickened distad, with apical portion forming a slightly protruding, short subrectangular lobe with its apical margin oblique in relation to the long axis of tibia, apical comb absent; aedeagus with a subapical group of dense, needle-like sclerites; parameres slightly recurved.

Description. Body of male ( Fig. 7 ) moderately slender, slightly flattened, pigmentation moderately dark brown with indistinctly darker head, vestiture light brown; BL 0.74 mm.

Head ( Fig. 15 ) broadest at eyes, HL 0.13 mm, HW 0.18 mm; tempora weakly arcuate, much shorter than eyes; posterior margin of vertex nearly straight, vertex and frons confluent and convex, except for distinctly flattened frontal area between and slightly behind supraantennal tubercles; supraantennal tubercles weakly elevated but welldefined; eyes large, strongly convex and coarsely faceted. Frons and vertex uniformly and evenly covered with small, shallow but relatively distinct and dense punctures; setae sparse, short and suberect, bristles on tempora and vertex well-visible; long posterolateral setae on vertex present (only the left seta visible in the studied specimen, the other one presumably broken off). Antennae slender, AnL 0.30 mm, antennomeres I and II strongly elongate, III–X each strongly transverse, XI about as long as broad.

Pronotum in dorsal view nearly circular, broadest distinctly in front of middle, PL 0.19 mm, PW 0.23 mm; anterior margin weakly arcuate; anterior corners not marked; sides strongly rounded in anterior half, weakly so in posterior half; posterior pronotal corners distinct, obtuse-angled; posterior margin weakly arcuate; pronotal base with distinct, relatively long transverse groove, lateral pits indiscernible. Punctures on disc fine, inconspicuous; setae sparse, short, suberect; lateral bristles sparse and moderately long.

Elytra together oval, broadest distinctly in front of middle, EL 0.43 mm, EW 0.33 mm, EI 1.31; humeral calli distinct; elytral base with large and deep basal impression; adsutural area indistinctly impressed in anterior half; apices of elytra separately rounded. Punctures on elytra dense but small, very shallow and with diffuse margins, inconspicuous; setae short, sparse and nearly recumbent.

Protibia ( Fig. 23 ) not thickened distad, with apical portion forming a slightly protruding, short subrectangular lobe with its apical margin oblique in relation to the long axis of tibia, apical comb absent.

Aedeagus ( Fig. 31 ) moderately slender, AeL 0.10 mm, endophallus lightly sclerotized, in subapical region with a large group of dense, needle-like sclerites directed distomesad; parameres slightly sinuate, each with one apical seta.

Female. Unknown.

Distribution. Japan, southern Shikoku.

Etymology. Locotypical, after the village of Yusuhara.

Remarks. This species is most similar to M. oharaensis ; similarities and differences were discussed in remarks for the latter species.

Figures

FIGURES 1–8. Dorsal habitus of males. Microscydmus okinawanus sp. n. (1); M. oharaensis sp. n. (2); M. nishimeanus sp. n. (3); M. kochiensis sp. n. (4); M. elytratus sp. n. (5); M. tibialis sp. n. (6); M. yusuharanus sp. n. (7); M. omogonus sp. n. (8).

FIGURES 9–16. Heads of males in anterodorsal view. Microscydmus okinawanus sp. n. (9); M. oharaensis sp. n. (10); M. nishimeanus sp. n. (11); M. kochiensis sp. n. (12); M. elytratus sp. n. (13); M. tibialis sp. n. (14); M. yusuharanus sp. n. (15); M. omogonus sp. n. (16). Arrowheads show posterolateral vertexal setae.

FIGURES 17–24. Apices of male protibia in dorsal (17–21, 22–24) and ventral (22) views. Microscydmus okinawanus sp. n. (17); M. oharaensis sp. n. (18); M. nishimeanus sp. n. (19); M. kochiensis sp. n. (20); M. elytratus sp. n. (21); M. tibialis sp. n. (22); M. yusuharanus sp. n. (23); M. omogonus sp. n. (24).

FIGURES 25–32. Aedeagus in ventral view. Microscydmus okinawanus sp. n. (25); M. oharaensis sp. n. (26); M. nishimeanus sp. n. (27); M. kochiensis sp. n. (28); M. elytratus sp. n. (29); M. tibialis sp. n. (30); M. yusuharanus sp. n. (31); M. omogonus sp. n. (32).