Hlavaciellus metrios Jałoszyński, 2011, sp. n.
Creators: name: Jałoszyński, Paweł
Publisher: name: Zenodo
Year: 2011
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Staphylinidae
Hlavaciellus
Hlavaciellus metrios

description: Hlavaciellus metrios sp. n.
(Figs. 25, 33, 34)
Type material. Holotype: MALAYSIA: ɗ, " SABAH 27a \ Crocker Range \ 1550–1650 m \ 16.V.1987 \ Burckhardt - Löbl" [white, printed], " HLAVACIELLUS \ metrios m. \ det. P. JAŁOSZYŃSKI, '09 \ HOLOTYPUS " [red, printed] (MHNG).
Diagnosis. Head of males non-modified; antennomere III only 1.2x as long as broad; antennomere XI less than twice as long as broad; aedeagus in ventral view very stout, in lateral view with strongly curved apices of parameres.
Description. BL 1.88. Body of male (Fig. 25) strongly convex, pigmentation light brown, vestiture yellowish.
Head large, HL 0.28, HW 0.48; vertex long and broad, regularly convex, confluent with convex frontoclypeal region; supraantennal tubercles prominent, distinctly separated from median part of frons; eyes large, strongly convex and coarsely faceted. Punctures on vertex and frontoclypeal region very small but relatively distinct, densely, unevenly distributed and separated by spaces 0.5–1.5 as wide as puncture diameters, supraantennal tubercles largely impunctate; setae moderately dense, long and suberect. Antennae nearly as long as 0.7 BL, very slender, gradually but only slightly thickened up to antennomere X, uniformly covered with thin, long, dense and suberect setae, AnL 1.30, antennomere I 1.5x as long as broad; II distinctly narrower and much shorter than I, slightly broader than long; III slightly larger than II, 1.2x as long as broad; IV slightly broader but not longer than III, 1.1x as long as broad; V much longer than IV but only slightly broader, 1.4x as long as broad; VI slightly larger than V, 1.4x as long as broad; VII slightly broader and distinctly longer than VI, 1.5x as long as broad; VIII as long as VII but slightly broader, 1.4x as long as broad; IX slightly larger than VIII, 1.3x as long as broad; X distinctly larger than IX, 1.4x as long as broad, with slant apical margin (external lateral margin is longer than internal one); XI about as broad as X and distinctly shorter than IX–X together.
Pronotum in dorsal view trapezoidal with weakly convex anterior margin, broadest at base but only slightly narrowing anteriorly, PL 0.50, PW 0.73; sides strongly rounded in anterior third, then slightly concave and minimally divergent towards sharp but not acute hind angles; posterior margin deeply bi-emarginate; ante-basal pits small and shallow but relatively well marked, each nearly equally distant from posterior and lateral margin of pronotum; lateral edges in posterior half indistinctly swollen. Pronotal disc very glossy, in middle covered with very fine and shallow punctures unevenly distributed and separated by spaces 0.5– 3 x as wide as puncture diameters, punctures close to margins of pronotum are larger and denser, but not coarse. Setae long, moderately dense, suberect to erect.
Elytra oval, relatively long, broadest between middle and anterior third, EL 1.10, EW 0.88, EI 1.26; basal pit on each elytron small but distinct, located very close to scutellum; subhumeral lines sharply marked, as long as 0.34x EL, only slightly divergent, each developed as border between higher humeral region and lower adsutural area; apices of elytra separately rounded. Punctures on basal half of each elytron small but much more distinct and denser than those on pronotum, separated by spaces equal to puncture diameters, gradually reducing in diameter and depth toward lateral margins and apices; setae similar to those on pronotum but slightly thicker and longer. Hind wings not studied.
Legs slender and long, tibiae straight or nearly straight.
Metaventrite with shallow and relatively small postmesocoxal impressions, as long as about half length of ventrite.
Aedeagus (Figs. 33, 34) stout and short, AeL 0.33; median lobe in ventral view with sides gradually narrowed towards triangular, pointed apex; internal armature distinctly asymmetrical; parameres in lateral view slender but strongly expanded and distinctly bent dorsally in subapical region, with strongly curved apices.
Female. Unknown.
Distribution. East Malaysia: Borneo, Sabah.
Etymology. The Greek adjective μέτρɩος (metrios), meaning "moderate, modest" was chosen to reflect the lack of any head modifications in males of this unremarkable species.
Remarks. Within the group of Hlavaciellus with non-modified heads, H. metrios can be recognized on the basis of its remarkably stout aedeagus, similar only to that of H. smetanai (with modified head). Hlavaciellus metrios differs from H. extremalis in long, sharply marked subhumeral lines and the antennomere III only slightly longer than broad (nearly twice as long as broad in H. extremalis), from H. miser in much stouter antennomere XI (<2x as long as broad vs. 2.2x in H. miser) and in shorter antennomere IV (only 1.1x as long as broad; in H. miser 1.5x); and from the most similar H. clandestinus in different proportions of the pronotum (PW/PL 1.45 in H. metrios vs. 1.36 in H. clandestinus).
description: Published as part of Jałoszyński, Paweł, 2011, Hlavaciellus Jałoszyński, 2006: eleven new species, detailed morphology and systematic position within Cephenniini (Coleoptera, Staphylinidae, Scydmaeninae), pp. 1-33 in Zootaxa 2763 on page 14, DOI: 10.5281/zenodo.276822