Ypsiloncyphon acer, Yoshitomi, Hiroyuki, 2015

Yoshitomi, Hiroyuki, 2015, New species of the genus Ypsiloncyphon (Insecta: Coleoptera: Scirtidae: Scirtinae), Zootaxa 3904 (4), pp. 451-500 : 476-477

Ypsiloncyphon acer sp. n.

( Figs. 13 H, 21)

Type material. Holotype ( EUMJ): male, “[North Thai] Maeo Khun Klang 1350 m, Doi Inthanon 21. X. 1983 M. Sakai”. Paratypes ( NSMT, NMW, EUMJ): 3 males, same data as for the holotype, s. no. HY 818; 1 male, same locality and collector, but 20. X. 1983; 1 male, “ THAILAND) Maeo Khun Klang, 1300 m Doi Inthanon 21. X. 1983 M. Tomokuni”.

Description. Male. Body ( Fig. 13 H) oval, convex dorsally, shining, closely covered with yellowish-white setae throughout. Coloration of body blackish-brown, but mouthparts, antennae and legs yellowish-brown; pronotum reddish-brown.

Head moderate in size, slightly convex dorsally, granulate, with straight front margin. Eyes moderate in size, prominent; the distance between eyes about 1.6 times as long as the maximum diameter of an eye. Antennae ( Fig. 21 A) short and stout; approximate ratio of each antennal segment (n = 1) as 5.0: 3.0: 1.0: 5.5: 5.6: 6.2: 6.2: 6.2: 6.5: 6.0: 9.0. Pronotum granulate as on head; front and lateral margins almost straight; antero-lateral corners about 120º, lightly produced anteriorly; postero-lateral corners about 120º; posterior margin bisinuous; PW/PL 2.23–2.56 (2.40). Scutellar shield small, sparsely punctate, equilaterally triangular. Elytra oval, widest in middle, closely covered with fine punctures; apices rectangular; humeral parts weakly projecting; EL/EW 1.25–1.36 (1.30); EL/PL 4.51–5.31 (4.81); EW/PW 1.52–1.56 (1.54); TL/EW 1.54–1.62 (1.58).

Caudal margin of sternite VII ( Fig. 21 B) arcuate. Tergite VIII ( Fig. 21 C) moderately sclerotized, trapezoidal, bearing long setae and short spines in apical part, with a pair of long apodemes; sternite VIII ( Fig. 21 E) moderately sclerotized, long rod-like shaped, expanded in apical part; tergite IX ( Fig. 21 D) moderately sclerotized, inversely U-shaped, sternite IX ( Fig. 21 F) moderately sclerotized, U-shaped, very long, pointed at apices. Tegmen ( Fig. 21 G) very long, moderately sclerotized, Y-shaped, bifid in apical 1/2; parameres very long, bearing short spines in apical part, with rounded apices. Penis ( Fig. 21 H) long, moderately sclerotized, about 0.7 times as long as tegmen; parameroids obtuse at apex, finely punctate; pala gently tapered in proximal 1/3; trigonium projecting from proximal 2/3 to 5/6, covered with small spines in apical part.

Female. Unknown.

Measurements. Male (n = 4): TL 1.93–2.02 (1.96) mm; PW 0.78–0.83 (0.81) mm; PL 0.32–0.35 (0.34) mm; EW 1.20–1.27 (1.24) mm; EL 1.58–1.70 (1.62) mm.

Distribution. Thailand.

Remarks. This species is closely related to Ypsiloncyphon formosus (Klausnitzer) in the characteristics of the male genitalia, and differs from it in the long parameres which bear short spines and a slender penis.

Etymology. The species name refers to the pointed sternite IX.

Figures

FIGURE 13. Habitus of Ypsiloncyphon spp., holotype, male (except for F). A) Y. guamensis sp. n., B) Y. philippinensis sp. n., C) Y. panayensis sp. n., D) Y. chlorizanoides sp. n., E) Y. bicolor sp. n., F) Y. bicolor sp. n., paratype, female, G) Y. sumatranus sp. n., H) Y. acer sp. n., I) Y. nokrekensis sp. n., J) Y. boukali sp. n., K) Y. javanicus sp. n., L) Y. nepalensis sp. n. Scales: 1.0 mm.

FIGURE 21. Ypsiloncyphon acer sp. n., holotype, male. A) antenna, B) sternites V – VII, C) tergite VIII, D) tergite IX, E) sternite VIII, F) sternite IX, G) tegmen, H) penis in ventral view.