Micrillus bispinosus, Assing, 2019

Assing, Volker, 2019, A revision of Palaearctic and Oriental Scymbalium and Micrillus IV. The Iauna of Cambodia (Coleoptera, Staphylinidae, Paederinae), Linzer biologische Beiträge 51 (1), pp. 21-31 : 29-30

Micrillus bispinosus nov.sp. ( Figs 18-24 ) T y p e m a t e r i a l: Holotype ♂: ̎ CAMBODIA - Siem Reap province, N Siem Reap city,,

13°26'29''N, 103°52'25''E, light trap, 12-13.XI.2018, leg. W. Rossi / Holotypus ♂ Micrillus bispinosus sp. n., det. V. Assing 2019̎ (cAss). Paratypes: 4♂♂, 9♀♀: same data as lectotype (cAss); 1♂, 2♀♀: ̎ CAMBODIA - Kampong Chhnang prov., Rolea B'ier distr., Toekchenh vill., 12°07'36''N, 104°38'05''E, light trap, 6.XI.2018, leg. W. Rossi ̎ (cAss) ; 9♂♂, 7♀♀: ̎ NW Cambodia, Siem Reap, 13°21'N, 103°51'E, 20 m a.s.l., killed by halogen light reflector, P. Kočárek leg., 7.-11.xi.2002 ̎ ( NMP, cAss) .

C o m m e n t: All the specimens from NMP were collected post-mortem and are consequently more or less distinctly damaged (legs and antennae partly or completely missing).

E t y m o l o g y: The specific epithet (Latin, adjective) alludes to the pair of sclerotized apical spines in the internal sac of the aedeagus.

D e s c r i p t i o n: Body length 4.2-4.9 mm; length of forebody 2.4-2.6 mm. Habitus as in Fig. 18 . Coloration: forebody more or less distinctly bicoloured with the head brown to blackish (rarely reddish), the pronotum bright reddish, and the elytra reddish to brown; legs yellowish to reddish-yellow; antennae reddish-yellow to reddish.

Head ( Fig. 19 ) weakly oblong, broadest across eyes, distinctly tapering posteriad behind eyes; dorsal surface with moderately 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. Apical palpomere of maxillary palpus slender, slightly less than half as long as maxillary palpomere III.

Pronotum ( Fig. 19 ) slender, 1.20-1.24 times as long as broad and more or less distinctly narrower than head; lateral margins straight, nearly parallel in dorsal view; posterior margin truncate; punctures moderately dense and of variable size; midline broadly impunctate; interstices without microsculpture.

Elytra ( Fig. 19 ) slightly longer than pronotum; punctation moderately fine and moderately dense; interstices without microsculpture; surface with some shine. Hind

wings fully developed. Protarsomeres I-IV not dilated. Metatarsomere I approximately as long as the combined length of II and III.

Abdomen ( Fig. 18 ) narrower than elytra; tergites with distinct and moderately sparse punctation bearing long and suberect 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; postero-lateral processes of segment IX circular in cross-section and approximately twice as long as tergite X ( Fig. 21 ).

♂: posterior excision of sternite VIII concave and moderately deep ( Fig. 20 ); aedeagus ( Figs 22-24 ) approximately 0.6 mm long, compact, and weakly sclerotized; internal sac with an apical pair of long and strongly sclerotized spines and with additional clusters of small spines.

C o m p a r a t i v e n o t e s: Based on the morphology of the aedeagus (capsule weakly sclerotized and symmetric; ventral process very short; internal sac with spines of various sizes), the shape of the male sternite VII (posterior excision concave and not very deep), and on the chaetotaxy of the abdomen (pubescence moderately sparse and partly composed of very long dark setae), this species belongs to the M. coloratus group, which previously included two species ( ASSING 2018). One of them, M. coloratus ASSING, 2018, has been recorded from Cambodia, the other, M. rougemonti ASSING, 2018, from Sri Lanka. The new species is reliably distinguished from the sympatric M. coloratus only by the shape and internal structures of the aedeeagus. It differs from the syntopic M. intermedius by usually darker elytra, sparser and longer pubescence of the abdomen, the shape of the posterior excision of the male sternite VIII ( M. intermedius : posterior excision very deep and narrow), and by the completely different shape of the aedeagus. For illustrations of M. coloratus and M. intermedius see ASSING (2018) and ASSING (2013), respectively.

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: The species is currently known from three localities in Siem Reap and Kampong Chhnang provinces, Cambodia. All the specimens were collected with light traps, together with M. virgatus , M. kongi , M. siamensis , and/or M. intermedius .

Figures

Figs 17-24: Micrillus variceps (17) and M. bispinosus (18-24): (17, 20) male sternite VIII; (18) habitus; (19) forebody; (21) abdominal segments IX-X; (22-24) aedeagus in lateral and in ventral view. Scale bars: 18-19: 1.0 mm; 17, 20-21: 0.5 mm; 22-24: 0.2 mm