Neolygus chaiyaphum n. sp.

Figs. 1J, 12D–E, 18L–O

Material examined. Holotype (♂). THAILAND: Chaiyaphum: Khon San District, Chulabhom Dam, 16˚32−33’N, 101˚38−39’E, 760−780 m alt., on flowers of broadleaf tree, 17 Apr 2013, T. Yasunaga (DOAT) (AMNH _ PBI 00378774).

Diagnosis. Currently known by a single male specimen. Recognized by its small size (4 mm in total length); ovoid body shape (Fig. 1J); pale olive basic coloration; dark apex of scutellum; widely darkened median part of hemelytra; and shape of parameres (Fig. 12D–E). Dorsal color pattern is most similar to that of N. esakii (Yasunaga, 1991) (cf. Fig. 3I; Yasunaga 2001; Noguchi et al. 2023); but the latter (Japanese indigenous) species has the obviously larger in size and different shape of the male parameres (Noguchi et al. 2023, p. 98, fig. 4), in addition to being associated with Acer spp. ( Sapindaceae) in cool temperate deciduous forests.

Description. Holotype male: Body ovoid, small; basic coloration pale olive green, with distinct dark macula on mesial part of dorsum (Fig. 1J); dorsal surface shining, with uniformly distributed, pale, simple, semierect setae. Head uniformly pale, shining; basal transverse carina on vertex slightly narrower than pronotal collar. Antenna pale brown; apical 1/6 of segment II, entire segments III and IV brown; segment II as long as metafemur; segment III slightly longer than head width across eyes. Labium pale brown, relatively long, slightly exceeding apex of metacoxa; apical part of segment IV dark brown. Pronotum and pleura pale olive; scent efferent system with somewhat elevated peritreme (Fig. 18M); apex of scutellum darkened. Hemelytron with median dark macula across clavus and corium (Fig. 1J); membrane smoky brown, with pale veins. All coxae and legs pale brown; metafemur apically with two obscure rings; meta-tarsomere II slightly longer than III (Fig. 18N). Abdomen uniformly pale olive.

Male genitalia (12D–E, 18O): Left paramere with stout, bulbous sensory lobe (Fig. 18O) and short apical process of hypophysis (Fig. 12E); sensory lobe of right paramere moderately produced at apex (Fig. 12D); vesical sclerites could not be observed, due to being a teneral specimen.

Female: Unknown.

Measurements: See Table 1.

Etymology. Named for the type locality, Chaiyaphum Province of Thailand; a noun in apposition.

Distribution. Thailand (Chaiyaphum).

Biology. A single male adult was collected from inflorescence of an undetermined broadleaf tree. No other information is currently available.

Remarks. Finding of this new species represents the first distributional record of Neolygus from Indochina. This distribution is perhaps similar to a range of mountains in central Taiwan, the Himalayas and highland areas in the Oriental Region that are known to harbor a number of glacial relicts or cryophilic elements of the Miridae (e.g. Yasunaga & Schwartz 2007).