Type material: HOLOTYPE; ♂; THAILAND (three labels in handwritten): ‘Thaïlande, distr. Kanchanaburi, Nam Tok, 17.VI.86, Tham Soi Yok Noi / Expédition Thai 86, P. Leclerc / Endogé près de Tham Soi Yok Noi, NAM TOK, KANCHANABURI, P. Leclerc Thai 86, 17.6.86’ (MHNG).

Diagnosis: Body length approximately 2.6 mm; dorsal surface of body segments covered with spatulate setae; head with indistinct, punctiform vertexal foveae; maxillary palpus extremely elongate; antennomere 9 and 10 greatly oblique on mesal margins, each with one markedly long and curved tuft of setae, antennomere 11 short, roundly triangular; pronotum only with punctiform median antebasal pit, roughly punctate at base; profemur with stiff setae along ventral margin, protibia distinctly curved and expanded to middle; aedeagus with endophallus composed of single curved sclerite, each paramere with two long apical setae.

Description: Body (Fig. 1A) length 2.61 mm; color reddish-brown, tarsi and mouthparts lighter. Surface of basal antennomeres, head, pronotum, elytra and abdomen covered with spatulate setae.

Head (Fig. 1B) lengthily sub-oval, slightly longer than wide, length 0.61 mm, width across eyes 0.53 mm, genal area roundly protruding laterally; vertex flat, barely convex, with tiny, indistinct vertexal foveae (dorsal tentorial pits); antennal insertions barely raised dorsally; frons broadly impressed medially, forming distinct rostrum, confluent with clypeus at middle through median keel; clypeus sharply descending, surface rough, anterior margin rounded and prominent; lacking ocular-mandibular carina. Venter with two tiny gular foveae (posterior tentorial pits) widely separated, lacking median carina or sulcus, anterior part of gular region strongly projecting ventrally. Maxillary palpus with palpomere 1 small, 2 lengthily pedunculate at base and enlarged apically, 3 pedunculate at base for short distance, widened apically, 4 fusiform, markedly elongate, slightly longer than 2. Compound eyes prominent laterally, each composed of approximately 48 ommatidia. Antenna elongate, length 1.81 mm, club (Fig. 1C) formed by enlarged apical three antennomeres; antennomere 1 thick and elongate, subcylindrical, 2-8 each moniliform, 2-5 successively shorter, 5-7 subequal in length, 8 shortest, 9 strongly oblique on lateral margin, broadest and with one long tuft of setae at base, 10 with broad and oblique lateral surface slightly impressed, with markedly long, curved tuft of setae at apicolateral margin, 11 roundly triangular, enlarged, shorter than 9 and 10 combined.

Pronotum (Fig. 1B) longer than wide, length 0.71 mm, width 0.60 mm, widest at middle; sides roundly expanded at widest point and smoothly convergent anteriorly and posteriorly; disc forming small, acute, tubercle just posterior mid-length, lacking carina or sulcus; with tiny, indistinct median antebasal pit; lacking lateral antebasal or basolateral fovea; roughly punctate at base. Prosternum with anterior part shorter than coxal part at middle, with small lateral procoxal foveae; hypomera fused with sternum, lacking ridge or pit; margin of coxal cavity not carinate.

Elytra much wider than long, length 0.86 mm, width 1.11 mm; each elytron with two large, asetose basal foveae; lacking discal striae; humeri weakly prominent, lacking subhumeral foveae or marginal striae; posterolateral margin with broad notch. Metathoracic wings fully developed.

Mesoventrite almost impunctate, median mesoventral fovea replaced by large, transversely oval opening, with large, setose lateral mesoventral foveae; inter-coxal process short, blunt at apex. Metaventrite confluent with mesoventrite, impunctate, slightly convex admesally; lacking fovea; posterior margin (metaventral process) roundly and narrowly emarginate at middle.

Legs elongate; all femora roughly punctate; protibia widened to middle, strongly arcuate, ventral margin of profemur with row of stiff setae.

Abdomen elongate, widest at posterolateral margins of tergite 1 (IV), length 0.77 mm, width 1.06 mm. Tergite 1 (IV) longest, with broad, deep and setose basal impression, with pair of lateral sockets and basolateral foveae, 2 (V) to 4 (VII) successively shorter, each lacking basal sulcus or fovea, 5 (VIII) transverse, with posterior margin shallowly and broadly emarginate at middle. Sternite 2 (IV) broadly and deeply sulcate at base, with large basolateral sockets, 3 (V) to 5 (VII) each short at middle, subequal in length, lacking fovea, 6 (VIII) strongly transverse, slightly convex at middle of posterior margin.

Aedeagus (Fig. 1D, E) short, length 0.17 mm, stout, dorso-ventrally symmetric; dorsal diaphragm large and oval, median lobe curved at apical portion and narrowing toward apex; parameres short, broad in lateral view, each with two long apical setae; endophallus armature composed of single sclerite strongly curved at middle, apical 1/4 much more strongly sclerotized than rest part. Female. Unknown.

Comparative notes: Within the genus, A. spatulatus sp. nov. has the most greatly modified antennomeres 9 and 10 in the male that each of them bears a markedly long, curved tuft of setae. In addition, the short, subtriangular terminal antennomeres, the spatulate setae of the body segments, and the unique form of the aedeagus readily separates this species from all known congeners.

Distribution: Thailand: Kanchanaburi Province.

Biological and collection information: The single male was collected from an endogean environment near Tham Soi Yok Noi, as indicated by the label data. However, the lack of any specialized morphological trait as well as the large eyes suggest this species is more likely epigean.

Etymology: The specific epithet spatulātus (-ta, -um) is a Latin adjective, meaning, “spatulate, spatula-like”, referring to the spatulate setae that cover the body surface.