Glischrochilus (Librodor) pilula, Jelínek & Hájek, 2018

Jelínek, Josef & Hájek, Jiří, 2018, Two new species of Glischrochilus with taxonomic comments, new records from Asia, and a world checklist of the genus (Coleoptera: Nitidulidae), Acta Entomologica Musei Nationalis Pragae (Acta. Ent. Mus. Natl. Pragae) 58 (2), pp. 567-576 : 568-571

Glischrochilus (Librodor) pilula sp. nov.

( Figs 1 , 3–6 )

Type locality. Laos, Houaphanh province, Phou Pane mountain near Ban Saluei village, ca. 20°15′N, 104°02′E.

Type material. HOLOTYPE: J ( NMPC), labelled: ‘NE Laos (Hua Phan prov.) / BAN SALUEI, Phu Phan Mt. / 20°15′N, 104°02′E / 26.IV.- 11.V.2001 / 1500-2000 m, J. Bezděk lgt. [p] // HOLOTYPE J / GLIS- CHROCHILUS / pilula sp. nov. / Jelínek & Hájek det.2018 [p, red label]’.

Description. Male holotype. Egg-shaped, strongly convex, glabrous, shining. Black, each elytron with two orange spots: basal one large, nearly oval, occupying most of basal third of elytron, reaching from scutellum to lateral margin, embracing black humeral bulge and not reaching suture; posterior one subtriangular, gradually narrowed laterad, reaching neither suture nor lateral margin. Tibiae dark reddish brown, basal antennomeres and all tarsi rusty, antennae becoming gradually darker distad, antennomeres VII–IX completely black. Body length 4.0 mm, width 2.3 mm ( Fig. 1 ).

Head slightly narrower than anterior margin of pronotum (ratio WPR3/HEAW = 1.03), temples obtusely rounded. Frons almost flat, punctures in middle larger than eyefacets and separated by 1.5–2.0 diameters, becoming closer around eyes as well as finer and closer anteriad; interspaces smooth and shining. Antennae slightly longer than width of head across eyes (ratio ANLE/HEAW = 1.03), antennal club occupying one third of antennal length (ratio ANCL/ ANLE = 0.31, oblong oval (ratio ANCL/ANCW = 1.93).

Pronotum widest near posterior angles, as wide as elytra, strongly narrowed anteriad (ratio WPR2/WPR3 = 1.77). Anterior margin straight, not bordered, anterior angles subrectangular, acutely pointed, prominent. Lateral margins not explanate, broadly arcuate, in basal fourth more strongly curved towards posterior angles; lateral rim becoming broader posteriad. Basal margin not bordered, subtruncate in front of scutellum, besides it twice indistinctly concave, running laterocraniad towards posterior angles, those obtuse, not projecting posteriad. Pronotal disc strongly convex, punctures distinctly finer than those of frons, nearly equal in size to eye facets, separated by 1.5–2.0 diameters; interspaces smooth and shining. Scutellar shield semicircular, finely diffusely punctate.

Elytra widest in basal third, as wide as pronotum, feebly narrowed anteriad and distinctly so posteriad, simultaneously rounded apically, as long as wide (ratio LELY/ WELY = 1.00). Lateral margins visible simultaneously from above in their entirety, not explanate. Sutural lines reaching midlength of suture. Surface of elytra strongly convex. Punctures diffuse, somewhat finer than those of pronotum, separated by more than one diameter; interspaces smooth and shining.

Pygidium almost flat, broadly subtruncate apically, densely and coarsely punctate; punctures nearly equal in size to those of frons, separated mostly by less than one diameter, interspaces smooth and shining with indistinct traces of reticulation.

Ventral part. Antennal furrows converging posteriad, deep with well defined margins. Mentum transverse with anterior margin broadly convex, densely punctate. Submentum transversely canaliculate, punctures slightly larger than eye facets, deep, separated by less than one diameter, interspaces obsoletely reticulate. Sides of submentum with pair of long golden setae projecting anteriad, as long as maximum width of mentum. Similar but shorter setae present also at base of maxillae. Ventral side of genae with coarse and deep punctures markedly larger than eye-facets, separated by less than one diameter, sometimes almost contiguous; interspaces reticulate. Prosternum bulged in middle, otherwise flat to slightly concave; punctures larger than eye facets, mostly separated by less than one diameter, interspaces obsoletely reticulate. Hypomera concave, impunctate except for some indistinct shallow punctures at inner margin. Prosternal process flat, becoming gradually wider distad, arcuately narrowed to truncate apical margin; in basal portion very coarsely rugosely punctate, behind procoxae almost impunctate safe a few widely dispersed small punctures, smooth and shining ( Fig. 3 ). Metaventrite broadly transversely convex, in middle flattened with shallow impunctate mediolongitudinal impression behind its midlength. Discrimen indistinct. Punctures somewhat larger than eye-facets, separated by several diameters, interspaces smooth and shining medially, obsoletely reticulate and moderately shining laterally. Posterior intercoxal margin subtruncate. Caudal marginal lines of mesocoxae interconnected by short straight transverse line in middle, bordering posterior margins of coxal cavities, their recurrent lateral portions vanishing in posterior half of metasternopleural sutures; axillary spaces small, impunctate. Punctation of abdominal ventrites analogous to that of metaventrite, generally somewhat finer.

Legs. Distances between pro-, meso- and metatibiae as 13:21:24. Pro- and mesofemora broadly oval, metafemora narrower; ratio LFE1/WFE1 = 2.20, LFE2/WFE2 = 2.30, LFE3/WFE3 = 2.50. Protibia subtriangular, straight; ratio LTI1/WTI1 = 3.36; outer subapical angle sharp, hardly projecting from outline of tibia. Mesotibia straight, subtriangular; LTI2/WTI2 = 3.41. Metatibia slenderer, LTI3/ WTI3 = 4.33. Protarsomeres I–III bilobed, dilated, 0.71× width of tibia. Tarsomere V as long as I–IV combined. Tarsal claws simple. Metatarsomeres I–III not bilobed, nearly half width of tibia.

Male genitalia. Tegmen oval, apically broadly rounded ( Fig. 5 ); median lobe almost parallel-sided, apex protruding, pointed ( Fig. 4 ); armature of endophallus as in Fig. 6 .

Female. Unknown.

Differential diagnosis. Glischrochilus pilula sp. nov. differs from other species of the genus in its short ovate body and not bordered basal margin of pronotum. The only short and broadly oval species of Glischrochilus hitherto known was G. octopunctatus ( Grouvelle, 1897) from Myanmar, originally placed in Cryptarcha Shuckard, 1840 by GROUVELLE (1897) and erroneously transferred to Eucalosphaera Jelínek, 1978 (= Calosphaera Jelínek, 1974 , non Campbell, 1951) ( JELÍNEK 1974, 1978). Its placement in Glischrochilus was established by KIREJTSHUK (1987), who proposed a distinct monobasic subgenus Gymnoparomius Kirejtshuk, 1987 for it. We were not able to study the latter species because the type of Cryptarcha octopuntata could not be found in BMNH collection (M. V. L. Barclay, pers. comm.). According to KIREJTSHUK (1987: 63) Gymnoparomius differs from Librodor in having (i) head narrower than half the width of pronotal base (i.e. ratio WPR1/HEAW <2), and (ii) prothorax ‘markedly’ lower than the height of metathorax near the top of elytral disc. In G. pilula sp. nov., ratio WPR1/HEAW = 1.81 and ratio height of metathorax / height of prothorax = 1.11 (being 1.07 in G. ruzickai sp. nov.). Thus Glischrochilus pilula sp. nov. does not differ from other species of Librodor in any substantial character other than comparative length of elytra, and we classify it as a member of this subgenus. In addition, Glischrochilus (Gymnoparomius) octopunctatus ( Grouvelle, 1897) , differs from G. (L.) pilula sp. nov. in narrower head capsule and different colour pattern: body red, base of pronotum and scutellum as well as elytra black, four elytral spots, tips of elytra and pygidium red to orange ( KIREJTSHUK 1987).

Etymology. Latin pilula = pill, noun in apposition, referring to the short convex body form.

Distribution. Known only from its type locality in northeastern Laos.

Figures

Figs 1–2. Dorsal habitus of Glischrochilus species. 1 – G. pilula sp. nov. (J holotype); 2 – G. ruzickai sp. nov. (♀ paratype, Myanmar).

Figs 3–11. Details of Glischrochilus species. 3–6 – G. pilula sp. nov.; 7–11 – G. ruzickai sp. nov. 3, 7 – prosternal process; 4, 8 – median lobe of aedeagus; 5, 9 – tegmen; 6, 10 – armature of endophalus; 11 – ovipositor. Scale bars = 0.25 mm.