Dayao pengzhongi Yin, Li and Zhao, here designated. Gender masculine.

Head and pronotum finely punctate. Head with vertexal foveae small, lacking frontal foveae; maxillary palpi with apical three segments elongate, each basally pedunculate and strongly protrude laterally. Pronotum with median and lateral antebasal foveae, lacking antebasal sulcus. Median metaventral fovea absent. Abdomen with tergite IV longest.

Length 2.95–2.99 mm. Head with narrow, long and prominent frontal rostrum, antennal tubercles faint; small vertexal foveae nude, with median carina between foveae; lacking postantennal notches and lateral postantennal pits; antennae with 11 antennomeres, antennal club formed by three enlarged apical antennomeres; maxillary palpi (Fig. 9) elongate, lateral projections of antennomeres II–IV each setose at their apices, fourth palpomeres with apical palpal cones; with lateral genal spines; gula flat, gular foveae close in median impression.

Pronotum with nude median and setose lateral antebasal foveae; lateral procoxal foveae present.

Each elytron with two basal foveae; discal stria extending from second basal fovea and exceeding elytral midpoint.

Thorax with median and lateral mesoventral foveae; lateral mesocoxal foveae present; lacking median metaventral fovea, metaventral apex broad and shallowly notched medially.

Legs with tarsomeres simple, third tasomeres about 0.75 times as long as second tarsomeres.

Abdomen with tergite IV (visible tergite I) longer than V–VII combined; tergite IV with deep basal sulcus connecting basolateral foveae, lacking mediobasal fovea in sulcus; with long discal carinae; tergites V–VII each with basolateral foveae. Sternite IV largest, longer than V–VII combined, with deep basal sulcus densely covered by short setae.

Males with antennomeres IX, pronotum and protibiae modified. Aedeagus with median lobe asymmetric; parameres long and symmetric; dorsal diaphragm oval.

A single species in known from Dayao Mountain, Guangxi Province, South China.

Dayao is placed near the genera of Pselaphodex complex with simple, linear tarsomere II not strongly bilobed, only slightly extending beneath tarsomere III: Paralasinus Hlaváč & Nomura, Lasinus Sharp, Linan Hlaváč, Indophodes Hlaváč, Labomimus Sharp and Pselaphodes Westwood. Among these genera, Dayao can be readily separated from Paralasinus and Lasinus by the clearly asymmetrical palpomeres II–IV, which are simple in both genera. Dayao is separated from Indophodes and Labomimus by the lack of a frontal and a median metaventral fovea; from Pselaphodes by the lack of a frontal fovea, the indistinct pronotal lateral antebasal foveae and the longer scape. The lack of a median metaventral fovea, the pronotum being finely punctate and the basal carinae of the tergite IV being much longer separate Dayao from Linan in which the median metaventral fovea is present, the pronotum is roughly and densely punctate and the basal carinae are much shorter.

The published key to the world genera of Tyrini (Hlaváč and Chandler 2005) may be modified as the following to accommodate the new genus:

The generic name is taken from the collection site of the type series, Dayao Mountain.

(1 ♂, 3 ♀♀). Holotype: ♂, labelled ‘CHINA: Guangxi Prov. / Laibin City, Jinxiu County / Dayao Mt., 7 km / 1, 200–1, 400 m, 22.vii.2011 / Z. Peng leg. // [red label] HOLOTYPE / Dayao pengzhongi Yin et al. / SHNU Collections’. Paratypes: 3 ♀♀, same label data as holotype, except ‘23.vii.2011 / Z.W. Yin & J.Y. Hu leg.’, all bear the following label: ‘[yellow label] PARATYPE / Dayao pengzhongi Yin et al. / SHNU Collections’.

Male (Fig. 1). Length 2.95 mm (holotype). Head lengthily and bluntly triangular, HL 0.74 mm, HW 0.59 mm, with decumbent setae. Vertexal foveae located posterior to point level with posterior margin of eyes. Eyes prominent, each with about 35 facets. Antennae elongate (Fig. 2), scape longer than II–IV combined, II–IV each short, of same width, V–VIII each longer than II–IV, slightly narrower, of same width, shortened distally, antennomeres of club (Fig. 8) of about same width, IX slightly expanded laterally at basal third, X shorter than IX and XI, XI longer than IX, with rounded apex. Pronotum (Fig. 4) as long as wide, PL 0.66 mm, PW 0.64 mm, with ‘Y’-shaped sulcus in anterior half, tufts of long golden setae at anterior margin of sulcus directed posteriorly. Elytra wider than long, EL 0.81 mm, EW 1.05 mm, lacking ridges. Venter (Fig. 6) with long metaventral process (Fig. 7) bent posteriorly near apex; metaventrite smooth, convex medially in apical half, with dense long setae at lateral portions and sparse minute setae at middle. Legs long, protibiae with small apical spines, pro- and mesofemora with distinct erect setae at ventral margins. Abdomen wider than long, AL 0.74 mm, AW 1.03 mm; discal carinae on tergite IV extending two-fifths of tergal length; tergite VIII transverse, narrowed apically in posterior half, with shallow median emargination, tergite IX (Fig. 10) semi-membranous, with apical portion strongly sclerotized; sternites VIII transverse. Aedeagus (Figs 11–13) length 0. 48 mm.

Female. In general similar to male. Antennomere IX (Fig. 3) and pronotum (Fig. 5) unmodified, metaventrite lacking process, protibiae simple. BL 2.81–2.99 mm, HL 0.71–0.73 mm, HW 0.57–0.59 mm, PL 0.63–0.66 mm, PW 0.62–0.64 mm, EL 0.74–0.78 mm, EW 1.07–1.10 mm, AL 0.73–0.82 mm, AW 1.12–1.15 mm. Eyes each with about 30 facets.

The specific name recognizes the efforts of Zhong Peng in collecting the male holotype.