Micrillus coloratus, Assing, 2018

Assing, Volker, 2018, A revision of Palaearctic and Oriental Scymbalium and Micrillus III. New species, new combinations, and additional records (Coleoptera: Staphylinidae: Paederinae), Linzer biologische Beiträge 50 (2), pp. 977-996 : 993-994

Micrillus coloratus nov.sp. ( Figs 9 , 34-40 )

T y p e m a t e r i a l: Holotype ♂: " CAMBODIA - Kampong Chhnang prov., Kampong Chhnang env., Toul Ompel , 12°14'14''N, 104°41'15''E, light trap, 19+ 21.V.2018, leg. Bernardi, Kong & Rossi / Holotypus ♂ Micrillus coloratus sp. n., det. V. Assing 2018" (cAss). Paratypes: 2♂♂, 2♀♀: same data as holotype (cAss).

E t y m o l o g y: The specific epithet (Latin, adjective) alludes to the distinctive coloration.

D e s c r i p t i o n: Body length 4.5-5.0 mm; length of forebody 2.5-2.8 mm. Habitus as in Fig. 34 . Coloration: forebody bicoloured with the head blackish-brown to black, the pronotum bright reddish, and the elytra reddish-yellow to dark-brown with reddish margins; abdomen pale-reddish; legs dark-yellowish; antennae yellowish-red.

Head ( Fig. 35 ) approximately as long as broad, broadest across eyes, distinctly tapering posteriad behind eyes; dorsal surface with fine and sparse punctation; median dorsal portion extensively impunctate; interstices with fine transverse microsculpture. Eyes large and distinctly convex, approximately as long as postocular region, or nearly so. Antenna approximately 1.5 mm long; antennomeres IV-V indistinctly oblong, preapical antennomeres transverse. Apical palpomere of maxillary palpus of slender conical shape, more than half as long as maxillary palpomere III.

Pronotum ( Fig. 35 ) slender, 1.20-1.24 times as long as broad and 0.90-0.95 times as broad as head; lateral margins straight, only indistinctly converging posteriad, nearly parallel in dorsal view; posterior margin nearly truncate; punctures moderately dense and of variable size; midline broadly impunctate; interstices glossy.

Elytra ( Fig. 35 ) as long as, or slightly longer than pronotum; punctation moderately fine and moderately dense, rather ill-defined; interstices without microsculpture; surface with some shine. Hind wings fully developed. Protarsomeres I–IV not dilated. Metatarsomere I slightly longer than the combined length of II and III.

Abdomen ( Fig. 36 ) narrower than elytra; tergites with distinct punctation bearing long and suberect to erect black setae and with interspersed punctures bearing fine pale setae; interstices with transverse microsculpture; posterior margin of tergite VII with palisade fringe; tergite X and sternite IX small ( Fig. 38 ); postero-lateral processes of segment IX approximately twice as long as tergite X ( Fig. 38 ).

♂: posterior excision of sternite VIII concave and moderately deep ( Fig. 37 ); aedeagus ( Figs 39-40 ) small in relation to body size, approximately 0.5 mm long, compact, and weakly sclerotized; internal sac with a basal pair of large and dark asymmetric structures and with a dark membranous apical structure.

C o m p a r a t i v e n o t e s: Based on the similar external and particularly on the similar male sexual characters, M. coloratus is undoubtedly closely allied to M. rougemonti from Sri Lanka (see below). It is distinguished from this species by smaller size, the coloration and shape of the head ( M. rougemonti : head distinctly oblong), shorter antennae, and by the shape and the internal structures of the aedeagus.

D i s t r i b u t i o n a n d n a t u r a l h i s t o r y: Thetypelocality( Fig.9 )and the collection data are identical to those of Scymbalium rossii , Micrillus virgatus , and M. kongi .

Figures

Fig. 9: Type locality of Scymbalium rossii, Micrillus virgatus, M. kongi, and M. coloratus. Photo: Walter Rossi.

Figs 34-40: Micrillus coloratus: (34) habitus; (35) forebody; (36) abdomen; (37) male sternite VIII; (38) abdominal segments IX-X; (39-40) aedeagus in lateral and in ventral view. Scale bars: 34-36: 1.0 mm; 37-38: 0.2 mm; 39-40: 0.1 mm.