Tmesiphorus costatus Weise, 1877

Inoue, Shota, Maruyama, Munetoshi & Nomura, Shûhei, 2019, Revision of the genus Tmesiphorus LeConte, 1849 (Coleoptera: Staphylinidae: Pselaphinae) from Japan, Zootaxa 4646 (1), pp. 67-86 : 69-71

Tmesiphorus costatus Weise, 1877

[Japanese name: Misuji-higekata-arizukamushi]

( Figs 1–3 )

Tmesiphorus costatus Weise, 1877: 99 (original description); Raffray, 1908: 374 (catalogue); Raffray, 1911: 157 (catalogue); Jeannel, 1958: 118 (diagnosis); Nomura, 2001: 158 (catalogue); Löbl and Besuchet, 2004: 327 (catalogue); Nomura, 2006: 101 (taxonomic note); Shibata et al., 2013: 97 (catalogue).

Type locality. Japan, Honshû , Yamaguchi-ken, Hagi-shi .

Type material. Holotype: 1♂, “ Japan, Hiller // Tmesiphorus costatus W.” ( MNHU).

Material examined. (5♂, 4♀). Japan: [Honshû]: 1♂, Iwate-ken, Miyako-shi, Genbeidaira , 9 VI 2007 , Y. Hi- rano leg. ( NSMT); 1♂, Ishikawa-ken, Suzu-shi, Misaki-machi , Suzu-jinja , 5–20 V 2018 K. Nakata leg. ( NSMT); 1♂, 1♀, Hiroshima-ken, Kamo-gun, Kurose-chô , 2 V 1988, I. Okamoto leg. ( NSMT); 1♀, Hiroshima, Kure-shi , 10 IX 1994, I. Okamoto leg. ( NSMT); 1♀, same data, but 2 V 1988 ( NSMT); 1♂, Hiroshima-ken, Higashihiroshimashi, Saijô-chô , Shitami , 17 IV 2014 , K. Maehara leg. ( KUM); 1♂, same data, but 24 IV 2014 ( KUM); 1♀, same data, but 18 IV 2017 ( KUM).

Diagnosis. Tmesiphorus costatus is readily distinguishable from the other Japanese congeners by a combination of strong sulcus on each elytron that extends from the median fovea to the posterior 2/3 of the elytra, and tergites IV–VI strongly carinate along their midlines. This species is smaller than the other Japanese Tmesiphorus species found in Honshû, Japan.

Redescription. Male ( Fig. 1-A ). Body length 2.37–2.47 mm. Body dark brown to reddish-brown, elytra testaceous.

Head ( Figs. 2-A, B ) about as long as wide, HL 0.46–0.50 mm, HW 0.44–0.49 mm, almost ovoid in dorsal view, coarsely punctate with setae; frons narrow, with longitudinal groove including fovea narrowed posteriorly to vertex; vertex with two foveae, with short longitudinal carina between vertexal foveae, shallowly depressed around vertexal foveae; eyes large, prominent; occiput rounded, with bundles of yellow setae; antennae ( Figs. 1-C, D ) slightly thick, antennomeres I thick, elongate, each 2.5 times longer than II; II as long as wide, each slightly wider than III; III–VI each longer than wide, narrowed at base, thickened apically; VII–VIII each transverse; VII each slightly longer than VIII; VIII each slightly wider than VII; IX–XI enlarged to form club, slightly curved inward in outer margin; IX each longer than wide, 1.3 times longer than I, 1.2 times wider than I, narrowed at base, thickened apically, longitudinally depressed with dense short setae on ventral surface; with a depression on ventral surface from basal 1/4 to apex, broadened apically, 1/3 as wide as segmental width on apical margin; X each longer than wide on inner margin, as long as wide on outer margin, longitudinally depressed with sparse setae on ventral side; XI slightly wider than IX at middle, produced outward, narrowed apically from middle, shallowly depressed with sparse setae on ventral side; maxillary palpi asymmetrical; segments II and III each with penicillate spine on lateral margin; segments IV thick, with rounded lobe on lateral margin, apical portion conical.

Pronotum ( Fig. 2-C ) about as long as wide, PL 0.50–0.55 mm, PW 0.50–0.53 mm; dorsum broadly round, widest anterior to middle, narrowed posteriorly, sparsely covered with setae, with distinct median and lateral foveae at base, with prominent convexity extending from anterior margin to median fovea; elytra ( Fig. 2-D ) much wider than long, EL 0.63–0.65 mm, EW 0.90–0.95 mm, coarsely punctate with setae; each elytron with basal median and inner foveae pubescent, with inner and lateral longitudinal carinae, strongly sulcate from median fovea to posterior 3/4 of elytra; inner carinae extending from between two basal foveae to posterior 3/4 of elytra; lateral carinae extending from anterior to posterior margin; posterior margin with thick brush-like yellow setae; profemora thickest, with white setae on anterior face; mesofemora as thick as metafemora; protibiae thickest, arcuate and thickened at middle, as long as mesotibiae; metatibiae longest; tibiae all with dense yellow setae at apices; tarsi ( Fig. 2-F ) elongate; tarsomeres II 2 /3 as long as III; protarsal claws asymmetrical, anterior claws each thicker than posterior one.

Abdomen ( Fig. 2-E ) large, AL 0.78 mm, AW 0.94–0.98 mm, wider than long, with sparse setae; tergite IV as long as VI; tergite V longest; tergite VII small; tergite VIII smallest, semicircular; tergites IV–VI each remarkably convex along midline; tergites IV and V each with lateral longitudinal carinae, those of tergite IV extending from anterior margin to posterior margin, those of tergite V extending from anterior to posterior margin; tergite IV with thick brush-like yellow setae along posterior margin.

Male genitalia ( Fig. 3 ) 0.31 mm in length, well-sclerotized, small, oval; parameres symmetric, projecting ventrally; each paramere with three setae; median lobe nearly symmetric, strongly projecting ventrally, slender; basal bulb broad, weakly narrowed apically; apical part slightly asymmetric; secondary gonopore small; endophallus elongate, circular at base.

Female ( Fig. 1-B ). BL 2.22–2.39 mm; HL 0.44–0.47 mm; HW 0.41–0.46 mm; PL 0.47–0.50 mm; PW 0.44–0.50 mm; EL 0.56–0.59 mm; EW 0.80–0.88 mm; AL 0.75–0.83 mm; AW 0.88–0.94 mm. Antennae with antennomeres II–VIII more slender than in male, successively broadening towards apices; antennomeres IX–XI not modified, smaller than in male, antennal club unmodified.

Distribution. Japan: Honshû (Iwate-ken, Ishikawa-ken, Hiroshima-ken, Yamaguchi-ken).

Biology. The specimens were collected by flight intercept traps ( FIT) or by sifting leaf litter.

Figures

FIGURE 1. A, B: Habitus of Tmesiphorus costatus, C, D: left antenna. A, male; B, female; C, antenna in dorsal view; D, antennal club in ventral view by SEM.

FIGURE 2. Tmesiphorus costatus, male. A, head in ventral view; B, head in dorsal view; C, pronotum; D, elytra; E, abdomen; F, left protarsus.

FIGURE 3. Male genitalia of Tmesiphorus costatus. A, ventral view; B, lateral view; C, dorsal view.