Amplicephalus (Nanctasus) anayensis sp. n.

(Figs 1–3)

Length. Male: 3.4–3.7 mm; female 3.8 mm.

Coloration and morphology. Nearly uniformly pale stramineous with indistinct yellow markings on head, pronotum, and mesonotum (Fig. 1A–B). Face mostly pale stramineous, with paired white marks (Fig. 1C). Abdominal sternites variably infused with dark brown. Femora and tibiae with dark brown marks (Fig. 1B–C).

Head wider than pronotum, anterior margin acutely angulate in dorsal view (Fig. 1A). Crown slightly longer medially than distance between eyes (Fig. 1A). Anteclypeus tapering apically, extended outer margin of gena. Lorum ovoid, slightly narrower than anteclypeus, well separated from lateral margin of face (Fig. 1C). Pronotum much shorter than crown (Fig. 1A). Forewing extended to or beyond apex of abdomen in both sexes, with a few extra crossveins (Fig. 1A–B).

Male genitalia. Pygofer lobe apex obliquely truncate, with numerous macrosetae in distal half (Fig. 2A–B). Valve broadly rounded caudally (Fig. 2C). Subgenital plate triangular, lateral margin nearly straight with macrosetae arising laterally (Fig. 2C). Style with articulatory arm long; preapical lobe acutely angulate; apophysis finger-like, nearly straight (Fig. 2D). Connective much shorter than aedeagus. Aedeagus apex with V-shaped emargination apically, sinuate in lateral view, arched dorsad in basal half then curved dorsad distally, dorsal hood at base well developed (Fig. 2D–E).

Female. Sternite VII with posterior margin weakly trilobed, medial lobe longest (Fig. 3E). Sternite VIII partially sclerotized, folded dorsad of sternite VII at rest, with pair of dark V-shaped median markings, one behind other, concealed but partly visible through integument of sternite VII as dark internal areas in uncleared specimens (Fig. 3E). First valvula with dorsal sculpturing imbricate, merging with short strigate ventral sculptured area distally (Fig. 3A–B). Second valvula moderately slender and nearly same width through most of length, dorsal margin with several small irregularly spaced teeth alternating between sides, toothed section slightly convex, apex gradually and evenly tapered to acute point (Fig. 3C–D).

Material examined. Holotype: ♂, Chile: Araucania, P.N. Nahuelbuta, Cerro Anay road, 1250 m, 37.80187°S, 73.01419°W, 18 Jan 2014, C.H. Dietrich, vacuum, grasses, CL 14–21–1 (MNC) . Paratypes: 1♂, 2♀, same data with holotype (INHS) .

Etymology. The species epithet is based on that of the type locality.

Remarks. This species is readily separated from other species of A. ( Nanctasus) by the relatively small size, pale overall coloration without distinct darker markings on the dorsum, and by the shape of the aedeagus and female sternite VII. It differs from other A. ( Nanctasus) species in the smaller size and more acutely produced head and is only tentatively included in this subgenus based on the presence of a membranous dorsal hood at the base of the aedeagal shaft and the few extra crossveins in the forewing (see Discussion below).