Aancistroger inarmatus sp. nov.

Figs. 32 G–H, 33A–C, 34G

Material examined. Holotype (male): Cambodia: Koh Kong, Tatai, (11°35'13''N, 103°5'50''E), 9–19.x.2016, leg. J. Constant & J. Bresseel (I.G.: 33.345 GTI project)—(Brussels RBINS).

Diagnosis. The new species differs from other species of the genus from which males are known by the absence of apico-lateral spines of the ninth tergite, only the tenth tergite is provided with upcurved spines; it also differs by the peculiar shape of the subgenital plate.

Description. Small to medium sized species. Head: Face narrow ovoid; forehead nearly smooth with very fine transverse riffles; fastigium verticis little wider than scapus; ocelli visible but little distinct; fastigium frontis not clearly separated from fastigium verticis; subocular furrows present but not strong (Fig. 32H). Abdominal tergites two and three each with two rows of stridulatory pegs (12–13, 15; 26,>16; n = 1 male).

Wings surpassing stretched hind tibiae (Fig. 32G). Tegmen: Radius with two branches, both forked near tip; media anterior free from base but leaning on radius, single branched; cubitus anterior at base single branched, after division into two branches before end of basal quarter, the anterior branch makes a curvature and receives a short connection branch from MA, shortly after it divides into MP and CuA1, which are running parallel; CuA2 without further division; cubitus posterior undivided, free throughout; on the right tegmen only there is a short crossing of CuA with CuP; with 3–4 anal veins; the fourth incomplete and with a long common stem with third anal vein.

Legs: Fore coxa with a small spine at fore margin; fore and mid femora unarmed; fore and mid tibiae with four pairs of large ventral spines and one pair of smaller ventral spurs; hind femur with 10 external and 5–6 internal spines on ventral margins; hind tibia with spaced spines on both dorsal margins, ventral margins with one preapical spine; with 3 apical spurs on both sides; dorso-internal apical spur little curved and about 1.6 times longer than dorso-external spur (Fig. 34G).

Coloration. General color uniformly yellowish brown. Face uniformly yellowish or greyish brown, indistinctly marbled in dried specimen. Tegmen semitransparent yellow, along fore and hind margins whitish; veins yellow; hind wing semitransparent white; veins yellow, cross-veins pale.

Male. Eighth abdominal tergite of normal length. Ninth abdominal tergite not globular but sloping posteriorly, only narrow lateral areas bent ventrad; apical margin in middle convex and down-curved forming a transverse lobe; on both lateral angles of this lobe with an inconspicuous, nearly vestigial upright process (Fig. 33A). Tenth abdominal tergite hidden under apical lobe of ninth tergite, with a pair of strong, hook-shaped, upright spines (Fig. 33B). Subgenital plate with wide, strongly bulging and little convex basal area, followed in middle by a short, transversely grooved central area, and a narrow strongly bulging apical area with bilobate apex, only along lateral margins flattened; without styli (Fig. 33C).

Female unknown.

Measurements (1 male).—body w/wings: 27; body w/o wings: 14.5; pronotum: 2.8; tegmen: 23; tegmen width: 7; hind femur: 7.5; antenna: 60 mm.

Etymology. The name of the new species refers to the absence of spines on the male ninth abdominal tergite: from Latin inarmatus (unarmed).