Stilicoderus bisinuatus, Assing, 2017

Assing, Volker, 2017, On Stilicoderus VI. Two new species from South Vietnam and additional records (Coleoptera: Staphylinidae: Paederinae), Linzer biologische Beiträge 49 (1), pp. 369-376 : 373-374

Stilicoderus bisinuatus nov.sp. ( Figs 1-9 , 16 )

T y p e m a t e r i a l: Holotype 3: "S VIETNAM: Lâm Dông Prov., Lac Durong Distr., Bidoup Nuiba Natl Park, surr. Giang Ly Ranger Station (1420-1460 m a.s.l.) 16-21.VI.2015 / legit L. Bartolozzi, G. Chelazzi, S. Bambi, F. Fabiano, E. Orbach, V. Sbordoni (n. Magazzino 3023) / Holotypus 3 Stilicoderus bisinuatus sp.n. det. V. Assing 2017" (VNMN). Paratypes: 13, 1♀: same data as holotype (MZUF, cAss) [paratype in MZUF registered as MZUF 18319].

E t y m o l o g y: The specific epithet (adjective) alludes to the strongly bisinuate posterior margin of the male sternite VII.

D e s c r i p t i o n: Body length 7.2-8.0 mm; length of forebody 4.8-5.0 mm. Elytra approximately as long and 1.2 times as broad as pronotum. External characters ( Figs 1-3 ) as in S. granulifrons , except as follows:

Head ( Figs 1-2 ) with lateral margins behind eyes weakly convex in dorsal view, posterior angles completely obsolete; interstices with extremely fine and dense microsculpture rendering the dorsal surface matt ( Fig. 16 ).

3: sternite VII ( Fig. 8 ) posteriorly with deep and broad excision, margin of this excision strongly bisinuate; sternite VIII ( Fig. 9 ) with broad and deep, somewhat obtusely Vshaped posterior excision; aedeagus ( Figs 4-7 ) 0.85 mm long (total length 1.1 mm); ventral process stout, strongly sclerotized, strongly curved, and apically acute in lateral view; apical internal structures slender and of subequal length (ventral view).

C o m p a r a t i v e n o t e s: Stilicoderus bisinuatus differs from the three other species of the S. granulifrons group as follows:

from S. granulifrons by a head of different shape and without shine ( S. granulifrons : head with glossy interstices; lateral margins behind eyes more strongly convex), broader elytra with more pronounced humeral angles, a much deeper and strongly bisinuate posterior excision of the male sternite VII, and by a larger aedeagus with a less strongly curved ventral process and with more strongly sclerotized apical structures of different shapes;

from S. confusus by a longer posterior portion of the head ( S. confusus : head more abruptly tapering posteriorly), a deeper and strongly bisinuate posterior excision of the male sternite VII, a differently shaped posterior excision of the male sternite VIII ( S. confusus : excision broadly concave), and the morphology of the aedeagus ( S. confusus : ventral process stouter and more strongly curved; apical structures shorter, less slender, and less strongly sclerotized);

from S. brachypterus by a head of different shape and without shine ( S. brachypterus : lateral margins behind eyes more strongly convex in dorsal view; interstices glossy), by longer and broader elytra ( S. brachypterus : elytra 0.81-0.86 times as long and approximately 1.1 times as broad as pronotum), a broader, deeper, and strongly bisinuate posterior excision of the male sternite VII, a less broad and less deep posterior excision of the male sternite VIII, and an aedeagus with a shorter ventral process and much more slender and more strongly sclerotized apical structures.

For illustrations of S. granulifrons , S. confusus , and S. brachypterus see ASSING (2016).

D i s t r i b u t i o n: The type locality is situated at about 12°08'N, 108°32'E in South Vietnam, at an altitude of approximately 1450 m.

Figures

Figs 1-7: Stilicoderus bisinuatus nov.sp.: (1) forebody; (2) head and pronotum; (3) antenna; (4-5) aedeagus in lateral and in ventral view (transparent preparation); (6-7) aedeagus in lateral and in ventral view (dry preparation). Scale bars: 1-3: 1.0 mm; 4-7: 0.5 mm.

Figs 8-15: Stilicoderus bisinuatus nov.sp. (8-9) and S. harpago nov.sp. (10-15): (8, 12) male sternite VII; (9, 13) male sternite VIII; (10) forebody; (11) antenna; (14-15) aedeagus in lateral and in ventral view. Scale bars: 10-11: 1.0 mm; 8-9, 12-15: 0.5 mm.

Figs 16-17: Stilicoderus bisinuatus nov.sp. (16) and S. harpago nov.sp. (17): (16) antero-median dorsal portion of head; (17) pronotum. Scale bars: 17: 0.5 mm; 16: 0.1 mm.