Revised from Viraktamath and Webb (2019). Adult. In full-face view, head broader than long (including eye margins), with upper portion appearing swollen in lateral view; frontoclypeus flat, horizontal, gradually expanding dorsally; clypellus parallel sides, convex, and extends beyond typical curvature of gena; lorum elongated and narrow; antennae originate near the upper corners of the eyes in frontal view, with pedicel visible from dorsal view. Tentorium with anterior arm thin, dorsal arm about as thin and half as long as anterior arm, arising at mid-length. Pronotum convex, with faint transverse rugosity, twice as wide as long medially, about as long as mesonotum, lateral margins carinate, convex anterior margin, slightly concave posterior margin. Mesonotum with faint transverse rugosity and granulose basal triangles. Forewing with separate claval veins, 3 subapical cells, open inner subapical cell, non-confluent veins R₄₊₅ and M₁₊₂. Hind wing with a marginal vein, either complete or discontinuous near apical region. Male genitalia. Male pygofer depressed, with setae in distal lower half; posterior margin of tergum IX shallowly U-shaped to receive abdominal segment X, with ventral marginal process variously developed (absent in M. omani). Subgenital plate with scattered setae on ventral surface and without apical membranous appendage. Style with well-developed lateral lobe, apophysis short, narrowed distally, surface sculptured. Connective and aedeagus fused, arms widely placed, parallel to each other. Aedeagus with two shafts fused in basal 0.2 to 0.5, then divergent, each with processes near apical gonopore. Female genitalia. Sternite VII approximately as long as VI, concave posterior margin. Valvula I more or less straight, strigate to concatenate (with sculpturing elements or scales fused to one another), or imbricate (with overlapping scales) ventrally at 1^st valvula apex, occupying slightly less than 0.5 distally, strigae oblique. In lateral view, valvula II almost straight, toothed area not preceded by either hyaline area or prominent tooth, occupying distal 0.5; tooth prominent, well separated from each other, without secondary dentition.

M. albinotata Cai & Ge, 1996: China (Cai and Ge 1996; Yang and Chen 2011)

M. creagra Zhao, Luo & Chen, 2024: China (Zhao et al. 2024)

M. confersa (Ishihara, 1961): Thailand (Ishihara 1961, Yang and Chen 2011)

M. flavida Cai & Ge, 1996: China (Cai and Ge 1996; Yang and Chen 2011)

M. hainanensis Yao, Yang & Chen, 2019: China (Yao et al. 2019)

M. lii Yang & Chen, 2011: China (Yang and Chen 2011)

M. maculata (Matsumura, 1912): China, Japan and Indonesia (Matsumura 1912; Hayashi 1996; Yang and Chen 2011);

M. nigra Kuoh & Kuoh, 1983: China (Yang and Chen 2011)

M. omani Viraktamath & Webb, 2019: India (Viraktamath and Webb 2019)

M. penthimioides Distant, 1908: Sri Lanka and India (Distant 1908; Yang and Chen 2011, Viraktamath and Webb 2019)

M. splendida Distant, 1908: Bangladesh, India and Pakistan (Distant 1908; Yang and Chen 2011, Viraktamath and Webb 2019, Ramaiah et al. 2023)

M. striola Zhao, Luo & Chen, 2024: China (Zhao et al. 2024)

M. vakra Viraktamath & Webb, 2019: India (Viraktamath and Webb 2019)

M. variabilis Evans, 1973: Indonesia (New Guinea) (Evans 1973; Yang and Chen 2011)

M. zonata Hayashi, 1996: Japan (Hayashi 1996; Yang and Chen 2011)

Thailand. Holotype • One male, Sakaerat Biosphere Reserve, Udomsub Sub-District, Wang Nam Khiao District, Nakhon Ratchasima Province, Thailand, 14°30'33.7"N, 101°56'23.4"E, 326 m a.s.l., 10.VI.2024, N. Kaewtongkum leg. (QSBG-2024-0046-0001); Paratypes • 10 males, same date, locality, and collector as holotype (QSBG-2024-0046-0002 to QSBG-2024-0046-0011) • 10 female, same date, locality and collector as holotype (QSBG-2024-0046-0012 to QSBG-2024-0046-0021) • 10 males, same date, locality, and collector as holotype (KKU-AG-I-0001 to KKU-AG-I-0010) • 10 female, same date, locality and collector as holotype (KKU-AG-I-0011 to KKU-AG-I-0020) • 5 males, same date, locality, and collector as holotype (SERS -I-H-2024-0001 to SBR-I-H-2024-0005) • 5 female, same date, locality and collector as holotype (SERS -I-H-2024-0001 to SBR-I-H-2024-0010) • 5 males, same date, locality, and collector as holotype (THNHM-I-00030082 to THNHM-I-00030086) • 5 females, same date, locality, and collector as holotype (THNHM-I-00030087 to THNHM-I-00030091).

Measurements. Male. Body length (including tegmen) 2.92 ± 0.12 mm (N = 10); head widths 0.87 ± 0.02 mm (N = 10). Female. Body length (including tegmen) 3.07 ± 0.11 mm (N = 10); head widths 0.92 ± 0.03 mm (N = 7).

Coloration. Male. Head (excluding eyes) entirely black in dorsal view, postclypeus dark brown with median area brown; lorum and gena dark brown; pronotum and scutellum dark brown; forewing dark brown, apical 1/4 with brown, yellow spot at mid-length extending to lateral margin of pronotum, oblique spot on costa, subtriangular spot near outer apical cell, small yellow spot near ScP+RA, hindwing brown, hyaline; wing veins brown; coxa and trochanter of all legs dark brown, femur, tibia and tarsi of fore and middle leg yellow; femur and tibia of hindleg brown, apex of tibia dark brown; basal half of 1 segmented tarsi segment pale brown, apical half dark brown, 2 segmented of tarsi pale brown, 3 segmented of tarsi and claw dark brown. Female. Similar to male.

Male genitalia. In lateral view, male pygofer subtriangular, approximately twice as length as high. In ventral view, valve subtriangular and wider than long and with anterior margin slightly concave and posterior margin produced medially. In ventral view, subgenital plate subrounded, with subtriangular shaped apex, inner margin roundly convex, outer margin almost straight, slightly concave near apex, basal part of subgenital plate with approximately 12 long setae, and distal part with 9–13 long setae. Style, slightly wider at base with lateral process, preapical lobe rectangular, strongly concave near apex. Apex of style digitiform and curved outward. Connective Y shaped, stem as long as arms. Aedeagus with a pair of arcuate laterobasal processes, nearly 1/3 as long as aedeagal shaft, and aedeagal shaft abruptly narrowed and curved inward in distal half, half portion in ventral view with a pair of spines pointed anteriorly. In lateral view, near apex of aedeagus with strong subtriangular lobe pointed anteriorly (Fig. 5).

Female genitalia. Female sternite VII subrectangular, approximately 2 times longer than wide, with pair subtriangular lobes at apex, outer margin convex and strongly emarginate in middle. Valvula I almost straight. Valvula II similar to valvula I, but 1/3-part upper margin serrate. Pygofer spinose in posterior half, ovipositor not exceeding pygofer (Fig. 6).

Thailand (Nakhon Ratchasima Province) (Fig. 2).

The specific epithet ‘sakaeratensis’ refers to the type locality.

The bamboo species Vietnamosasa pusilla (A.Chev. & A.Camus) T.Q. Nguyen has been identified as the host plant for Mukaria sakaeratensis sp. nov., a newly described species of bamboo-feeding leafhopper discovered in the Sakaerat Biosphere Reserve, Thailand. This finding marks the first documented ecological relationship between the bamboo genus Vietnamosasa and members of the tribe Mukariini (Hemiptera: Cicadellidae: Deltocephalinae), which are specialized herbivores feeding exclusively on bamboos. The genus Vietnamosasa comprises sympodial bamboos found in Southeast Asia, including Thailand, Cambodia, Laos, and Vietnam. Vietnamosasa pusilla, commonly found in dry dipterocarp forests, is characterized by its small size and adaptation to fire-prone environments. During the collection of the new species of Mukaria, the plant height, measured from the base of the stem (at the soil surface) to the tallest part of the plant, was approximately 70–90 cm.

In this study, genetic distances were calculated for the cytochrome c oxidase subunit I (COI) gene across several Mukaria species. The intraspecific genetic distances ranged from 0.10% to 0.20%, indicating relatively low genetic variation within individual species. When comparing between species, the interspecific genetic distances varied considerably, with the highest value of 23.71% observed between M. bambusana and M. maculata (2). Conversely, the lowest interspecific genetic distance was 12.07%, found between M. sakaeratensis sp. nov. and M. splendida (Fig. 7). These analyses revealed a clear barcoding gap (K2P) of 0.20–12.07% for the COI gene in Mukaria, demonstrating that this gene region effectively discriminates between different species within this genus while maintaining consistency within species. This substantial genetic differentiation supports the taxonomic distinctiveness of these Mukaria species, particularly the newly described M. sakaeratensis. In the maximum likelihood and Bayesian inference analyses, as well as the ABGD and ASAP methods, the new species was clearly distinct from other species included in the analysis (Fig. 8). Based on the COI phylogenetic tree, the new species was found in Indochina, while its closely related species, M. maculata, has been reported in Japan, Indochina, and Sundaland (Matsumura 1912; Hayashi 1996; Yang and Chen 2011). The phylogenetic analysis revealed strong branch support for the distinctiveness of the new species, highlighting its divergence from other species within the genus. Geographic distribution patterns indicate that most species of Mukaria have limited ranges, except for M. maculata, which exhibits a broader distribution across multiple biogeographic regions. This wide range suggests potential cryptic diversity within M. maculata, warranting further examination to determine whether populations from different regions represent distinct species. Additionally, the barcoding gap (K2P) observed in genetic distance analyses underscores the utility of COI for distinguishing species within Mukaria. These findings provide valuable insights into the phylogenetic relationships and biogeographic structure of this genus.

The genus Mukaria is distributed in the southeastern Palaearctic, Oriental and Oceanic regions. Three species were reported in Southeast Asia, i.e., M. confersa, M. maculata and M. variabilis. Prior to this study, there was a long gap of 63 years during which no new species of the genus were reported from Thailand. Ishihara (1961) reported a female of M. confersa from the northern region (Chiang Mai Province) of the country. The female of M. confersa differs from new species by 1) forewing apex black or varying degrees of brown, rest of wing and portion of disc of face light colored; and 2) light color spot on upper part (R-vein) of fore wing was connected with spot on lower part (M-vein) (see fig. 88 in Ishihara, 1961). The wing color and shape of the style of the new species is similar to M. maculata (see plate I, fig. 3 in Qiang et al. 2017), M. splendida (see fig. 3a in Viraktamath and Webb 2019; fig. 2g in Ramaiah et al. 2023). The new species can be distinguished from the closely related M. maculata by the following characteristics: 1) hook-shaped (curved-inward) of apex male aedeagus (Y-shaped of apex male aedeagus in M. maculata); 2) having a pair of spines pointed anteriorly at middle portion of male aedeagus on inner margin of arms (absent in M. maculata); and 3) length of middle area of male aedeagus as long as arms (length of middle area of male aedeagus shorter than arms in M. maculata). Based on the results from the phylogenetic and species delimitation analysis of the COI gene (Fig. 8), Mukaria maculata specimens (MG736688, MG736689, MG736690) and Mukaria maculata (MG736687) are placed into different clades in the phylogenetic analysis. The divergence seen in the phylogenetic tree might be due to taxonomic misidentification or inaccuracies in determining that both groups belong to M. maculata. These clades should be re-examined using detailed morphological, ecological, and genetic data to confirm their taxonomic assignment to M. maculata.