Ypsiloncyphon bifurcatus, Yoshitomi, Hiroyuki, 2015

Yoshitomi, Hiroyuki, 2015, New species of the genus Ypsiloncyphon (Insecta: Coleoptera: Scirtidae: Scirtinae), Zootaxa 3904 (4), pp. 451-500 : 457-458

Ypsiloncyphon bifurcatus sp. n.

( Figs. 1 D, 5)

Type material. Holotype ( EUMJ): male, “(BORNEO IS.) Poling nr Ranau Sabah, Malaysia 28. IV. 1980 M. & A. Sakai”.

Description. Male. Body ( Fig. 1 D) oblong, convex dorsally, shiny, closely covered with silver setae. Coloration of body yellowish-brown, but antennae and legs paler.

Head relatively large, flat dorsally, finely punctate, straight front margin of clypeus. Eyes large, prominent; the distance between eyes about 2.0 times as long as the maximum diameter of an eye. Antennae long and slender, reaching about proximal 1/3 of elytra. Pronotum punctate as on head, depressed in lateral parts; antero-lateral corners right-angled; anterior margin straight; lateral and posterior margins gently arcuate; postero-lateral corners obtuse; PW/PL 2.00. Scutellar shield equilaterally triangular. Elytra oblong, subparallel-sided near base to apical 1/ 4, densely punctate; humeral parts projecting dorso-laterally; apices right-angled; EL/EW 1.54; EL/PL 4.44; EW/ PW 1.44; TL/EW 1.88. Legs relatively long and slender.

Caudal margin of sternite VII ( Fig. 5 A) arcuate. Tergite VIII ( Fig. 5 B) moderately sclerotized, trapezoidal, bearing short spines in apical part, with a pair of slender apodemes. Sternite VIII ( Fig. 5 D) well sclerotized, small, T-shaped. Tergite IX ( Fig. 5 C) slightly sclerotized, trapezoidal, with a pair of long apodemes. Sternite IX ( Fig. 5 E) well sclerotized, U-shaped, pointed at apices. Tegmen missing. Penis ( Fig. 5 F) long, moderately sclerotized, subparallel-sided near base to apical 1/8; pala oblong, gently tapered basally; parameroids long, undivided, densely punctate, gently tapered apically; trigonium short, apex bilobed, minutely serrate in apico-lateral parts.

Female. Unknown.

Measurements. Male (n = 1): TL 1.47 mm; PW 0.54 mm; PL 0.27 mm; EL 1.20 mm; EW 0.78 mm.

Distribution. Malaysia (Borneo).

Remarks. This species is similar to Ypsiloncyphon bicornutus sp. n. in having an oblong body shape, the coloration of body, and male genital structure, but differs from the latter in the following characteristics: 1) trigonium somewhat longer, serrate in lateral margin, and 2) parameroids connected to each other (separated in bicornutus ), and 3) small body size, ca 1.5 mm (ca 2.2 mm in bicornutus ).

Etymology. The species name refers to the forked trigonium.

Figures

FIGURE 1. Habitus of Ypsiloncyphon spp., holotype, male (except for K). A) Y. laosensis sp. n., B) Y. myanmarnus sp. n., C) Y. nomurai sp. n., D) Y. bifurcatus sp. n., E) Y. bicornutus sp. n., F) Y. borneensis sp. n., G) Y. brachytrigonium sp. n., H) Y. garoensis sp. n., I) Y. kedahensis sp. n., J) Y. prolongatus sp. n., K) Y. mendosus (Klausnitzer, 1980), non-type specimen, male. Scales: 1.0 mm.

FIGURE 5. Ypsiloncyphon bifurcatus sp. n., holotype, male. A) sternites V – VII, B) tergite VIII, C) tergite IX, D) sternite IX, E) tegmen, F) penis in ventral view.