Batriscenellus suthepensis Yin & Kleeberg, sp. nov.

(Figs 1A, 2)

Type material. HOLOTYPE: THAILAND: ♂, ‘N-Thailand, Chiang Mai, Doi Suthep National Park, Nov. 2019 / Mok Fa waterfall, leaf litter, 08.11.2019, leg. Kleeberg’ (MNB). PARATYTYPES: THAILAND: 1 ♂, 4 ♀♀, same collection data as holotype (MNB, SNUC).

Diagnosis. Male: dorsal surface of head and pronotum finely punctate. Head with thick median carina extending from posterior margin of vertex to above anterior margin of eyes; trichomes on anterolateral margins of antennomeres 1 small, indistinct. Pronotum with strongly sinuate lateral longitudinal sulci. Abdominal tergite 1 (IV) broadly and shallowly impressed in posterior half, surface of impression densely covered with short setae. Aedeagus with large basal capsule and strongly twisted, broad dorsal lobe. Female: genital complex of unique form.

Description. Male (Fig. 1A). Body reddish-brown, length (from anterior margin of clypeus to posterior margin of abdomen) 1.98–2.04 mm. Head sub-quadrate, length from anterior margin of clypeus to posterior margin of vertex 0.44–0.45 mm, width across eyes 0.46 mm; dorsal surface (Fig. 2A) smooth and finely punctate, frons rough; antennal tubercles moderately prominent; vertexal foveae nude, distinct, situated at level of middle of eyes, anterior margin of vertexal sulcus straight; antennae elongate, length 1.02 mm, clubs weakly indicated by apical three antennomeres; ocular-mandibular carina distinct; eyes strongly prominent, each composed of 30 large ommatidia. Pronotum (Fig. 2A) about as long as wide, length along midline 0.47 mm, maximum width 0.45 mm; disc finely punctate; lateral longitudinal sulci strongly sinuate; with two small, acute antebasal denticles. Elytra slightly wider than long, length along suture 0.65–0.66 mm, maximum width 0.74–0.77 mm; discal striae extending to apical 4/5 of elytral length; with distinct humeral calli; with complete marginal striae originating from small subhumeral foveae. Legs elongate and slender, apical portions of pro- and metafemora with short sensory setae. Abdomen (Fig. 2B) wider than long, length along midline 0.54 mm, maximum width at base of tergite 1 (IV) 0.66 mm; tergite 1 (IV) longer than 2–4 (V–VII) combined, with broad and shallow impression occupying posterior half of tergite, surface of impression covered with dense, short setae; discal carinae lengthily triangular, widely separated; single marginal carina extending posteriorly to half of tergal length; weakly sclerotized sternite 7 (IX) (Fig. 2C) transverse, suboval. Aedeagus (Fig. 2 D–F) asymmetric, length 0.24 mm; basal capsule (slightly collapsed in Fig. 2) strongly dilated; ventral lobe short and broad, expanded at apex; dorsal lobe much longer and wider than ventral lobe, strongly curved ventrally and narrowed at apex; parameres fused to form short ventral membrane.

Female. Similar to male in general appearance and size. Antennae slightly shorter. Each eye composed of 23 facets. Tergite 1 (IV) lacking modification. Genital complex as in Fig. 2G, length along midline 0.22 mm, maximum width 0.24 mm. Measurements of body segments (as for male): body length 1.99–2.02 mm, length of antennae 0.94 mm, length/width of head 0.39–0.43/ 0.43–0.45 mm, pronotum 0.43–0.44/ 0.44–0.47 mm, elytra 0.54–0.55/ 0.69– 0.70 mm, abdomen 0.55–0.58/ 0.65 mm.

Comments. The new species is distinct, and can be readily separated from all congeners by the unique forms of the broad, shallow cavity of tergite 1 (IV) (Fig. 2B) of the male, and genital complex of the female.

Distribution. Thailand: Chiang Mai.

Etymology. The new specific epithet refers to Suthep National Park, type locality of the new species.