Amaurodera varicollis, Assing, 2016

Assing, Volker, 2016, On some Lomechusini of the Palaearctic and Oriental regions (Coleoptera: Staphylinidae: Aleocharinae), Beiträge Zur Entomologie = Contributions to Entomology 66 (1), pp. 13-111 : 92

Amaurodera varicollis spec. nov.

( Figs 143 , 149 , 432–434 )

Type material: Holotype ♂: “ Sumatra: N Sum. #29a, 5 km W Berastagi, Tongkoh , 1450 m, 3.XII.1989, Löbl, Agosti, Burckhardt / Holotypus ♂ Amaurodera varicollis sp. n., det. V. Assing 2015” ( MHNG).

Paratypes: 5 ♂♂, 1 ♀: same data as holotype ( MHNG, cAss) .

Etymology: The specific epithet (Latin, adjective: with variable pronotum) alludes to the variable morphology of the pronotum.

Description: Body length 4.2–5.3 mm; length of forebody 2.1–2.5 mm. Coloration: body brown to dark-brown with the anterior abdominal segments sometimes slightly paler; legs yellowish with (the apices of) the profemora sometimes, and with the apical portions of the meso- and metatibiae always more or less distinctly infuscate; antennae yellowish-brown to brown, with the basal and the apical antennomeres usually paler dark-yellowish; maxillary palpi yellowish.

Head ( Fig. 149 ) oblong, 1.06–1.16 times as long as broad, broadest across eyes, with more or less pronounced sexual dimorphism; punctation sparse and extremely fine; microsculpture subject to sexual dimorphism. Eyes relatively small, slightly more than half as long as distance from posterior margin of eye to posterior constriction of head. Antenna ( Fig. 143 ) 3.0– 3.2 mm long and very slender; antennomere IX more than twice as long as broad; antennomeres IV–VII approximately five times as long as broad.

Pronotum ( Fig. 149 ) 0.84–0.99 mm long and of rather variable shape, 1.32–1.45 times as long as broad, and 1.02–1.09 times as broad as head, with rather variable, more or less pronounced sexual dimorphism; dorsal and lateral surface not meeting at an obtuse angle posteriorly; microreticulation reaching lateral margins neither anteriorly nor posteriorly; narrow median furrow anteriorly terminating at some distance from anterior margin of pronotum.

Elytra ( Fig. 149 ) 0.50–0.55 times as long as pronotum; punctation extremely fine and moderately sparse; interstices with shallow or nearly obsolete microreticulation; pubescence moderately long and semi-erect. Hind wings present. Metatarsomere I approximately as long as the combined length of II and III.

Abdomen narrower than elytra; punctation fine and very sparse on all tergites; tergites with shallow microreticulation; posterior margin of tergite VII with palisade fringe; posterior margin of tergite VIII distinctly serrate.

♂: head shallowly impressed along the middle and with nearly obsolete to distinct microsculpture; pronotum in antero-median portion more or less distinctly impressed, with more or less reduced microreticulation, and more or less glossy; median lobe of aedeagus ( Figs 432–433 ) of rather variable size, 0.7–0.8 mm long, with conspicuously prominent crista apicalis; paramere 0.6–0.7 mm long, with rather short, broad, and flattened apical lobe.

♀: head with shallow median impression, this impression somewhat shorter and shallower than in male, dorsal surface with nearly obsolete microreticulation; pronotum in antero-median portion only slightly more glossy than on remainder of dorsal surface; spermathecal capsule ( Fig. 434 ) 0.32 mm long, with weakly dilated distal portion and with large and proximally distinctly dilated proximal portion.

Comparative notes: Amaurodera varicollis differs from other congeners known from Sumatra particularly by the variable pronotum and by the shape of the aedeagus. The spermatheca somewhat resembles that of A. kraepelini , from which A. varicollis is distinguished by much longer and more slender antennae, longer legs, the coloration (much paler antennae and legs; yellowish maxillary palpi), a more slender head, a sexually dimorphic pronotum, an aedeagus with a much more prominent crista apicalis, and a spermatheca with an even more dilated proximal, a stouter median, and a more dilated distal portion with a larger and deeper apical cuticular invagination.

Distribution and natural history: The type locality is situated to the west of Berastagi (3°10'N, 98°31'E) in Sumatera Utara, North Sumatra ( Indonesia). The specimens, some of which are apparently slightly teneral, were collected at an altitude of 1450 m.

Figures

Figs 119–143. Drusilla bifida (119–122), Rabdotodrusilla pectinata (123–125), Amaurodera arunica (126–127, 132), A. gilvios (128, 133), A. reticulata (129, 134), A. dentata (130, 135), A. parvoculata (131, 136), A. thailandensis (137–138), A. fasciata (139), A. meorum(140),A. disparicollis (141), A. spinans (142),andA. varicollis(143):forebody (119, 123, 126, 128–131); head and pronotum (120); antenna (121, 124, 132–143); abdomen (122, 125, 127). Scale bars: 1.0 mm.

Figs 144–159. Amaurodera thailandensis (144–145), A. fasciata (146), A. meorum (147), A. spinans (148), A. varicollis (149), A. disparicollis, male (150), A. disparicollis, female (151), Tetrabothrus nilgiricus (152–153), T. pubescens, syntype (154–156), T. collucatus (157–158), and T. neoguineensis, holotype (159): forebody (144–152, 154, 157, 159); abdomen (153, 156); antenna (155, 158). Scale bars: 144–154, 156–157, 159: 1.0 mm; 155, 158: 0.5 mm.

Figs 420–441. Amaurodera meorum (420–422), A. disparicollis (423–429), A. spinans (430–431), A. varicollis (432–434), Tetrabothrus nilgiricus (435–436), T. indicus (437–439; 439: lectotype), andT. inflexus fromLaos (440–441): spermatheca (420–422, 429, 434); male pronotum (423–424); female pronotum (425–426); median lobe of aedeagus in lateral and in ventral view (427–428, 430–433, 435–437, 440); ventral process of aedeagus (438–439, 441). Scale bars: 423–426: 1.0 mm; 420–422, 427–441: 0.2 mm.