Ypsiloncyphon brachytrigonium, Yoshitomi, Hiroyuki, 2015

Yoshitomi, Hiroyuki, 2015, New species of the genus Ypsiloncyphon (Insecta: Coleoptera: Scirtidae: Scirtinae), Zootaxa 3904 (4), pp. 451-500 : 461-462

Ypsiloncyphon brachytrigonium sp. n.

( Figs. 1 G, 9)

Type material. Holotype ( NMW): male, “NE-INDIA: Meghalaya W Garo Hills Nokrek NP; ca. 1100 m ”, “ 25º29.6’N 90º19.5’E 9.- 17.5.1996 leg. Jendek & Sausa”, genit. s. no. HY 910.

Description. Male. Body ( Fig. 1 G) oval, convex dorsally, shiny, closely covered with white setae. Coloration of head, scutellar shield, elytra, meso- and metaventrites, and abdomen blackish-brown, but anterior half of head paler; mouthparts, antennae, pronotum and legs yellowish-brown, but proximal parts of middle and hind femur infuscate.

Head moderate in size, slightly convex dorsally, finely punctate, with gently arcuate front margin of clypeus. Eyes large, prominent; the distance between eyes about 2.0 times as long as the maximum diameter of an eye. Pronotum finely punctate, slightly depressed dorsally in lateral parts; anterior and lateral margins almost straight; posterior margin gently arcuate; antero- and postero-lateral corners obtuse; PW/PL 2.29. Scutellar shield moderate in size, finely punctate, equilaterally triangular. Elytra oval, widest at the middle, densely punctate; humeral parts slightly projecting dorsally; apices right-angled; EL/EW 1.30; EL/PL 4.29; EW/PW 1.44; TL/EW 1.61.

Caudal margin of sternite VII ( Fig. 9 A) straight on a short stretch. Tergite VIII ( Fig. 9 B) moderately sclerotized, semicircular, with elongate projections protruding from basal part of lateral margin, with a pair of long apodemes; tergite IX ( Fig. 9 C) moderately sclerotized, consisting of a pair of hemitergites, with a pair of plate-like projections in mesal parts, pointed and slightly curved interiorly at apices. Tegmen ( Fig. 9 D) long, moderately sclerotized, Y-shaped, bifid in apical 1/2 (parameres), pointed at apices. Penis ( Fig. 9 E) moderately sclerotized, as long as tegmen; pala oblong, constricted in basal 1/8, almost straight in basal margin; parameroids relatively short, evenly tapered posteriorly, pointed at apex, sparsely punctate; trigonium very short, situated in apical 1/5, ovate in apical part.

Female. Unknown.

Measurements. Male (n = 1): TL 1.85 mm; PW 0.80 mm; PL 0.35 mm; EW 1.15 mm; EL 1.50 mm.

Distribution. India.

Remarks. This is a remarkable species in having distinctive shapes of tergites VIII–IX and the short, oddly ovate trigonium of the penis. Related species are unknown.

Etymology. The species name refers to the short 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 9. Ypsiloncyphon brachytrigonium sp. n., holotype, male. A) abdominal sternites III – VII, B) tergite VIII, C) tergite IX, D) tegmen, E) penis in ventral view.