Lathrobium inflatum, Assing, 2013

Assing, V., 2013, On the Lathrobium fauna of Japan (Coleoptera: Staphylinidae: Paederinae), Linzer biologische Beiträge 45 (1), pp. 1615-1641 : 1632

Lathrobium inflatum nov.sp. ( Figs 36-43 )

T y p e m a t e r i a l: Holotype 3: "Gumma Pref., Mt. Hotaka (foot), ca 1300 m, 14-15.viii.80 / JAPAN: Honshu, B.M. 1980-492, P.M. Hammond / Holotypus 3 Lathrobium inflatum sp.n., det. V. Assing 2013" ( BMNH).

E t y m o l o g y: The specific epithet is the past participle of the Latin verb inflare (to inflate) and alludes to the large basal portion of the internal structure of the aedeagus.

D e s c r i p t i o n: Small species; body length 6.0 mm; length of forebody 2.5 mm. Habitus as in Fig. 36 . Coloration: body reddish-brown with the abdominal segments V- VII somewhat darker; legs pale yellowish-brown; antennae reddish.

Head ( Fig. 37 ) approximately as long as broad; punctation moderately coarse and rather sparse, interstices distinctly broader than diameter of punctures, with shallow microreticulation. Eyes small, weakly convex, and composed of approximately 25 ommatidia, approximately one fourth as long as postocular region in dorsal view. Antenna 1.5 mm long.

Pronotum ( Fig. 37 ) 1.25 mm long and approximately as broad as head; punctation similar to that of head, but distinctly denser; impunctate midline moderately broad.

Elytra ( Fig. 37 ) moderately short, 0.65 times as long as pronotum; punctation fine and shallow. Hind wings completely reduced.

Abdomen slender, but distinctly broader than elytra; punctation very fine and very dense; interstices with distinct microreticulation; posterior margin of tergite VII without palisade fringe.

3: protarsomeres I-IV strongly dilated; tergite VIII with weakly convex posterior margin; sternites III-VI unmodified; sternite VII ( Fig. 38 ) strongly transverse and with shallow postero-median impression, posterior margin weakly concave, pubescence unmodified; sternite VIII ( Fig. 39 ) weakly oblong, pubescence unmodified, posterior excision Vshaped and moderately deep; aedeagus ( Figs 40-43 ) 1.0 mm long; ventral process symmetric, slender and subapically weakly curved in lateral view, and apically acute; dorsal plate with long, stout, strongly sclerotized, and apically acute apical portion and with long, slender, lamellate, and weakly sclerotized basal portion; internal sac with two sclerotized structures, one of them moderately long, slender, apically acute, and basally bifid and the other basally very large, apically extending into a long, slender, strongly curved, asymmetric spine.

♀: unknown.

C o m p a r a t i v e n o t e s: Based on the similar external characters, the shape and chaetotaxy of the male sternite VII and VIII, and particularly on the similarly derived morphology of the aedeagus (internal sac with a basally strongly inflated sclerotized structure), L. inflatum undoubtedly belongs to the L. sinense group. In external characters, it is practically indistinguishable from the similar L. nikkoense , but differs by the completely different shapes of the internal structures of the aedeagus.

D i s t r i b u t i o n: The type locality is situated at the foot of Hotaka-san (36°48'N, 139°08'E] in the north of Gunma Prefecture, Honshu, at an altitude of approximately 1300 m.

Figures

Figs 36-43: Lathrobium inflatum nov.sp.: (36) habitus; (37) forebody; (38) male sternite VII; (39) male sternite VIII; (40-41) aedeagus in lateral and in ventral view; (42) dorso-apical portion of aedeagus in lateral view; (43) apical portion of aedeagus in dorsal view. Scale bars: 36-37: 1.0 mm; 38-43: 0.5 mm.