Scymbalium rossii, 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 : 979-980

Scymbalium rossii nov.sp. ( Figs 1-9 )

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 ♂ Scymbalium rossii sp. n., det. V. Assing 2018" (cAss). Paratype ♀: same data as holotype (cAss).

E t y m o l o g y: This species is dedicated to Walter Rossi (L'Aquila), to whom I am grateful for the generous gift of all the Cambodian specimens treated in this paper.

D e s c r i p t i o n: Body length 7.0- 7.7 mm; length of forebody 3.7-4.1 mm. Habitus as in Fig. 1 . Body somewhat depressed. Coloration: head and pronotum reddish-brown; elytra reddish; abdomen dark-brown to blackish-brown with the apex (segments VIII-X and the posterior portion of VII) reddish; legs yellowish-red; antennae red.

Head ( Fig. 2 ) 1.10-1.15 times as broad as long; integument with double punctation, with coarse and dense macropunctures and with interspersed micropunctures; median dorsal portion with somewhat sparser punctation; interstices without microsculpture. Eyes approximately as long as postocular region in dorsal view. Antenna long and very slen- der, approximately 3.0 mm long; antennomeres IV-XI at least approximately twice as long as broad and club-shaped, i.e., basally very thin and apically distincty dilated, broadest anterior to apex. Maxillary palpus with short and conical apical palpomere, this palpomere approximately one-third as long as palpomere III.

Pronotum ( Fig. 2 ) 1.12-1.15 times as broad as long, broadest near anterior angles, distinctly tapering posteriad; lateral margins straight or weakly sinuate in the middle; posterior margin weakly concave in the middle; macropunctation dense, slightly less coarse than that of head; micropunctation scattered, sparser than that of head; midline moderately broadly impunctate.

Elytra ( Fig. 2 ) approximately as long as pronotum; punctation rather fine and dense. Hind wings fully developed. Protarsomeres I–IV distinctly dilated in both sexes. Metatarsomere I approximately as long as the combined length of II and III.

Abdomen ( Fig. 3 ) approximately as broad as elytra; punctation distinct and very dense, similar to that of elytra; interstices glossy, with extremely fine and nearly obsolete transverse microsculpture visible only at high magnification (100 x); posterior margin of tergite VII with palisade fringe; tergite X and sternite IX unmodified, not of reduced size; postero-lateral processes of segment IX approximately 1.5 times as long as tergite X, apically with a spine curved upwards.

♂: posterior excision of sternite VIII narrow and short, about one-eighth a long as length of sternite ( Fig. 4 ); aedeagus ( Figs 5-8 ) slender, with short hooked apex (lateral view), and with heavily sclerotized internal structures.

C o m p a r a t i v e n o t e s: This species is evidently closely allied to S. anale and S. persimile . It is distinguished from both of them by smaller size, paler coloration of the forebody, and coarser punctation of the abdomen. It additionally differs from S. anale by a posteriorly less strongly tapering pronotum, relatively larger eyes, a much shorter and narrower posterior excision of the male sternite VIII, and by a much smaller aedeagus ( S. anale : aedeagus approximately 2.0 mm long) with an apex of different shape in lateral view. The male sexual characters of S. persimile are unknown.

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 type locality is situated near Kampong Chhnang in the estuary of the effluent of Tonle Sap lake ( Fig. 9 ), Cambodia. The specimens were collected with a light trap, together with seven species of Micrillus (one of them undescribed).

Figures

Figs 1-8: Scymbalium rossii: (1) habitus; (2) forebody; (3) abdomen; (4) male sternite VIII; (5-6) aedeagus in lateral and in ventral view; (7-8) apex of aedeagus in lateral and in ventral view. Scale bars: 1-3: 1.0 mm; 4: 0.5 mm; 5-6: 0.2 mm; 7-8: 0.1 mm.

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