Liliputella microscopica sp. nov.

(Figs 1–9)

Type material. Holotype (PAPUA NEW GUINEA): ♂, two labels: "Bismarck Isl. Dyaul / Kollepine Berlese nr. 16. / 12.March 1962 / Noona Dan Exp. 61-62" [white, printed, with "Berlese nr. 16." handwritten], " LILIPUTELLA / microscopica m. / P. Jałoszyński, 2016 / HOLOTYPUS " [red, printed] (ZMUC).

Diagnosis. As for genus (vide supra).

Description. Body of male (Fig. 1) elongate and slender, nearly parallel-sided, strongly flattened, light brown and covered with light brown setae; BL 0.68 mm.

Head (Figs 1, 3) in dorsal view subtriangular with rounded sides, broadest shortly in front of occipital constriction, HL 0.15 mm, HW 0.18 mm; vertex with indistinct posteromedian impression, anteriorly confluent with subtriangular frons. Dorsal surface of head covered with fine and unremarkable punctures and short, moderately dense suberect setae. Antennae (Fig. 4) short and slender, with flagellum gradually thickened distally; AnL 0.25 mm; scape and pedicel elongate, antennomeres III–X each transverse, XI slightly shorter than IX–X combined, about twice as long as broad, with broadly rounded apex.

Pronotum in dorsal view (Fig. 5) indistinctly bell-shaped, with rounded sides, broadest near anterior fourth, as broad as head; PL 0.20 mm, PW 0.18 mm; Anterior margin rounded; posterior margin with indistinct median flattening. Punctures on pronotal disc fine, inconspicuous; setae short, sparse and erect.

Elytra (Fig. 1) nearly parallel-sided and only slightly broader than pronotum, broadest slightly in front of middle, EL 0.33 mm, EW 0.21 mm, EI 1.53. Humeral denticles distinct. Elytra covered with shallow and fine punctures; setae longer than those on head and pronotum, sparse, nearly recumbent.

Legs (Fig. 1) short and robust; protibiae strongly, meso- and metatibiae slightly curved.

Aedeagus (Figs 8–9) elongate, AeL 0.13 mm; median lobe in ventral view broadest in basal half, apical region slightly narrowing, apex truncated and shallowly emarginated; in lateral view median lobe slightly curved. Endophallus extruded, with two long tubular structures and one loop of flagellum; parameres slender but short, each with one long apical seta.

Female. Unknown

Distribution. Bismarck Archipelago, Dyaul Island (the Islands Region of Papua New Guinea).

Etymology. The name microscopica refers to the tiny body of this species.

Remarks. Liliputella microscopica shows morphological adaptations to subterraneous life, as lack of eyes and wings and light pigmentation. On the other hand, the large ventral cephalic cavity surrounded by setae seems to be a glandular structure, and may suggest an inquilinous habit.