Ypsiloncyphon bicornutus, Yoshitomi, Hiroyuki, 2015

Yoshitomi, Hiroyuki, 2015, New species of the genus Ypsiloncyphon (Insecta: Coleoptera: Scirtidae: Scirtinae), Zootaxa 3904 (4), pp. 451-500 : 458-459

Ypsiloncyphon bicornutus sp. n.

( Figs. 1 E, 6)

Type material. Holotype ( EUMJ): male, “Gn. Alab., Tambunan, Sabah, BORNEO 7. II. 2008 H. Takizawa leg.”, “genitalia in slide No. HY 1116”.

Description. Male. Body ( Fig. 1 E) oblong, convex dorsally, shiny, closely covered with silver setae. Coloration of body reddish-brown, but antennomeres V–XI and meso- and meta-thoraces dark brown.

Head relatively large, slightly convex dorsally, finely punctate; clypeus narrow and long, shallowly concave in front margin. Eyes large, prominent; the distance between eyes about 1.9 times as long as the maximum diameter of an eye. Antennae relatively short, reaching about proximal 1/4 of elytra. Pronotum punctate as on head, strongly depressed in lateral parts; antero-lateral corners obtuse; anterior margin bisinuous; lateral and posterior margins gently arcuate; postero-lateral corners rather pointed; PW/PL 1.88. Scutellar shield equilaterally triangular. Elytra oblong, subparallel-sided near base to apical 1/4, densely punctate; humeral parts weakly projecting; apices rightangled; EL/EW 1.63; EL/PL 4.50; EW/PW 1.47; TL/EW 2.00. Legs relatively large and slender.

Caudal margin of sternite VII ( Fig. 6 A) arcuate. Tergite VIII ( Fig. 6 B) moderately sclerotized, wide, upturned in posterior margin bearing short setae, with a pair of short and slender apodemes. Tergite IX ( Fig. 6 C) slightly sclerotized, trapezoidal, bearing short spines along posterior margin, with a pair of long and stout apodemes. Sternite IX ( Fig. 6 D) short, moderately sclerotized, Y-shaped. Tegmen ( Fig. 6 E) well sclerotized, U-shaped; parameres subparallel-sided, long, pointed at apices. Penis ( Fig. 6 F) long, about 1.3 times as long as tegmen, moderately sclerotized; pala with open basal margin; parameroids long, wide, separated, sparsely punctate; trigonium short and wide, projecting from basal 1/2, bifurcate at apex.

Female. Unknown.

Measurements. Male (n = 1): TL 2.20 mm; PW 0.75 mm; PL 0.40 mm; EL 1.80 mm; EW 1.10 mm.

Distribution. Malaysia (Borneo).

Remarks. This species is closely related to Ypsiloncyphon bifurcatus sp. n., but is distinguished from it by the characteristics mentioned in the remarks for Y. bifurcatus sp. n.

The character state of the separated parameroids this species are also present in other species (e.g., Y. micans , Y. minutulus , Y. mendosus , Y. disparatus , Y. remotus , and Y. yayeyamanus ). These species probably evolved independently, because they belong to different species groups.

Etymology. The species name refers to the bicornated 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 6. Ypsiloncyphon bicornutus sp. n., holotype, male. A) sternites V – VII, B) tergite VIII, C) tergite IX, D) sternite IX, E) tegmen, F) penis in ventral view.