Hlavaciellus cincinnalis Jałoszyński 2021, sp. n.

Hlavaciellus cincinnalis sp. n.

(Figs 1–4, 25)

Type material. Holotype: MALAYSIA (Sabah): ♂, three labels: “(N. BORNEO) / Headquarter / Mt. Kinabalu / 1. V. 1980 / M. & A. Sakai ” [white, printed], “Collection / of Ent. Lab. / Ehime Univ.” [blue, printed], “ HLAVACIELLUS / cincinnalis m. / P. Jałoszyński, 2021 / HOLOTYPUS” [red, printed] (EUMJ).

Diagnosis. Body large, exceeding 2 mm in length; head in male modified, with median ‘lock’ of dense setae inserted between pair of tiny tubercles far above level of posterior margins of eyes, and flanked by another pair of similar tubercles situated more anteriorly and separated by distance twice as wide as posterior tubercles, setal ‘lock’ directed anterad; pronotum distinctly narrower than elytra; each of antennomeres 3–10 at least slightly elongate; aedeagus in ventral view stout, slightly less than 3 times as long as broad and distinctly narrowing from base to apex; parameres with conspicuously thick subapical setae.

Description. Body of male (Fig. 1) moderately stout, strongly convex, uniformly light brown; setae slightly lighter than cuticle; BL 2.10 mm.

Head (Fig. 2) broadest at large, strongly convex and coarsely faceted eyes, HL 0.30 mm, HW 0.51 mm; frons unmodified, only indistinctly convex; supraantennal tubercles prominent; vertex indistinctly convex and modified in its posterior region, far beyond eyes, with two pairs of tiny tubercles forming trapeze, and with slender median tuft of dense setae inserted between posterior tubercles and directed anteriorly. Punctures on frons and vertex fine, inconspicuous; setae moderately dense and long, suberect. Antennae slender, AnL 1.45 mm, BL/AnL 1.45; scape indistinctly elongate, pedicel about as long as broad, antennomeres 3–10 each slightly or distinctly elongate, 11 distinctly shorter than 9–10 combined, twice as long as broad.

Pronotum subtrapezoidal, broadest at base; PL 0.60 mm, PW 0.78 mm, PI 0.77; anterior margin strongly rounded; sides with finely crenulate lateral carinae, indistinctly sinuate; posterior corners slightly sharp-angled and with acute tips; posterior margin shallowly bisinuate; pronotal disc strongly convex, with area at each posterior corner distinctly impressed; antebasal pits equally distant from lateral and posterior margins. Punctures on pronotum fine and inconspicuous; setae long, dense, suberect.

Elytra together oval, broadest distinctly in front of middle; EL 1.20 mm, EW 0.95 mm, EI 1.26; subhumeral lines sharply marked, each developed as step-wise border between elevated humeral region and median area, as long as 0.3 EL; sides of elytra strongly rounded; elytral apices separately rounded. Punctures and setae similar to those on pronotum.

Legs long and slender, unmodified.

Aedeagus (Figs 3–4) elongate but not very slender; AeL 0.45 mm; median lobe in ventral view slightly less than 3 times as long as broad, tapering from base to apex; endophallic structures poorly sclerotized, indistinct; parameres with conspicuously thick subapical setae.

Female. Unknown.

Distribution. Northern Borneo (Fig. 25).

Etymology. The adjective cincinnalis is derived from the Latin noun cincinnus, a lock of hair; the name refers to the median ‘lock’ of setae on the vertex.

Remarks. Hlavaciellus cincinnalis belongs to large-bodied species, clearly exceeding 2 mm in length. The conspicuous tuft of setae on the vertex inserted between a pair of small tubercles and flanked by another pair of more anteriorly situated tubercles is a unique apomorphy of this species and allows for unambiguous identification.