Microscydmus (Microscydmus) nishimeanus, Jałoszyński, 2019

Jałoszyński, Paweł, 2019, Unexpected diversity of Microscydmus Saulcy & Croissandeau in Japan (Coleoptera: Staphylinidae: Scydmaeninae), Zootaxa 4679 (3), pp. 539-552 : 542-544

Microscydmus (Microscydmus) nishimeanus sp. n.

( Figs 3 , 11 , 19 , 27 )

Type material. Holotype: JAPAN (Okinawa Pref.): ♂, three labels: " Mt. Nishimedake (No. 1) / (epiphytic fern: litter) / Kunigami-son, Okinawa Is. / [ Ryukyus : JAPAN] / 20.iv.2001, S. Karasawa " [white, printed]; " Epiphytic Fern Survey / Scydmaenidae / Microscydmus sp. 1 / P. Jałoszyński det.,2005" [printed, creamy], " MICROSCYDMUS (s. str.) / nishimeanus m. / P. Jałoszyński, 2019 / HOLOTYPUS " [red, printed] ( NSMT) . Paratypes (11 exx.): 8 ♀♀ and 3 exx. of unknown sex (undissected), same data as for holotype, except for yellow PARATYPUS labels (cPJ, NSMT) .

Diagnosis. Body length 0.90–0.98 mm; posteromedian portion of vertex with punctures larger and denser than those on surrounding areas; bristles on tempora and vertex short and sparse, barely discernible; protibia strongly thickened in apical region, with apical comb of six curved teeth that occupy only apical margin, proximal teeth of the same length and shape; aedeagus with a pair of short, transverse subapical structures connected at middle, and with strongly elongated, asymmetrical lateral components flanking a long tubular structure; parameres nearly straight.

Description. Body of male ( Fig. 3 ) slender, slightly flattened, pigmentation dark brown, vestiture light brown; BL 0.95 mm.

Head ( Fig. 11 ) broadest at eyes, HL 0.20 mm, HW 0.23 mm; tempora weakly arcuate, about as long as eyes; posterior margin of vertex weakly arcuate, vertex and frons confluent and convex; supraantennal tubercles weakly elevated but well-defined; eyes large, strongly convex and coarsely faceted. Frons and vertex covered with small and shallow but dense and distinct punctures, which on posteromesal portion of vertex are slightly larger than those on surrounding areas; setae sparse, short and suberect, bristles on tempora and vertex barely discernible; vertex with a pair of long posterolateral setae. Antennae slender, AnL 0.38 mm, antennomeres I and II strongly elongate, III–X each transverse, XI about as long as broad.

Pronotum in dorsal view nearly circular, broadest at middle, PL 0.25 mm, PW 0.28 mm; anterior margin weakly arcuate; anterior corners not marked; sides strongly rounded, except for posterior 1/5, where margins are distinctly sinuate; posterior pronotal corners distinct, obtuse-angled; pronotal base with a well-defined, short transverse groove, additionally with one tiny pit near each hind corner. Punctures on disc fine and inconspicuous, smaller and shallower than those on head; setae sparse, short, suberect; lateral bristles short and sparse.

Elytra together oval, broadest slightly in front of middle, EL 0.50 mm, EW 0.38 mm, EI 1.33; humeral calli distinct; elytral base with large and deep basal impression that extends posterad as a broad, shallow and diffuse groove; narrow adsutural region in anterior half of each elytron slightly impressed; apices of elytra separately rounded. Punctures as indistinct as those on pronotum; setae short, sparse and nearly recumbent.

Protibia ( Fig. 19 ) strongly thickened in apical region, with apical comb of six curved teeth that occupy only apical margin, proximal teeth of the same length and shape.

Aedeagus ( Fig. 27 ) moderately slender, AeL 0.13 mm, endophallus with long median tubular component flanked by a pair of shorter elongate and clearly asymmetrical sclerites in submedian region of median lobe, in subapical region the tubular component connected to a pair of short, oval transverse sclerites; parameres nearly straight, each presumably with one apical seta (seta broken off, but its socket visible).

Female. Externally similar to male, also with thickened protibiae, but lacking apical combs, most specimens lighter brown than male, punctures on vertex and frons variable, from similar to those in male to more evenly distributed and less conspicuous; BL 0.90–0.98 mm (mean 0.94 mm); HL 0.19–0.20 mm (mean 0.20 mm), HW 0.20–0.23 mm (mean 0.22 mm), AnL 0.33–0.35 mm (mean 0.34 mm); PL 0.24–0.25 mm (mean 0.25 mm), PW 0.25–0.28 mm (mean 0.27 mm); EL 0.48–0.53 mm (mean 0.50 mm), EW 0.33–0.35 mm (mean 0.34 mm), EI 1.41–1.50.

Distribution. Japan, Okinawa-jima.

Etymology. Locotypical, after Mt. Nishime (= Nishime-dake).

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

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).