Stiliderus agostii, Rougemont, 2015

Rougemont, Guillaume De, 2015, Studies on Stiliderus Motschulsky and Stilicoderus Sharp: biogeographical notes and descriptions of new species (Coleoptera: Staphylinidae: Paederinae), Stuttgarter Beiträge zur Naturkunde A, Neue Serie 8, pp. 113-130 : 127

Stiliderus agostii n. sp.

Holotype (♂): Indonesia, Sulawesi Sel. W. of Mamasa , 1600 m, 9.IV.1991, D. AGOSTI, F91724 ( MHNG) .

P a r a t y p e: 1 ♂, same data as holotype ( CRO) .

Description

Body length ca. 5.2 mm. Proportions of holotype: length of head: 71; breadth of head: 74; diameter of eye: 23; length of antennomeres: I: 28; II: 9; III: 15; IV: 13; V: 13; VI: 13; VII: 12; VIII: 10; IX: 10; X: 10; XI: 15; length of pronotum: 70; breadth of pronotum: 61; length of elytron: 70; breadth of elytra: 80; metatibia: 81; metatarsomeres: I: 11; II: 8; III: 5; IV: 8; V: 15.

Head and pronotum black, elytra brown, abdomen fuscous, labrum brown, mouthparts and antennae and legs rufo-testaceous, the femora somewhat infuscate. Forebody see Fig. 30 . Head transverse, sub-quadrate, the puncturation close, the interstices on average smaller than diameter of punctures on vertex, the punctures becoming elongate near base, the interstices very densely micropunctate, the surface therefore dull. Pronotum elongate, widest at posterior two-fifths, densely and finely granulose with a narrow, entire, raised mid-longitudinal line, the granules serially arranged in a chevron pattern extending from mid-longitudinal line towards apico-lateral angles in posterior two-thirds. Elytra transverse, subquadrate, depressed, with large punctures more or less serially aligned especially laterally, the interstices very densely microsculptate, the surface dull.

Male: abdominal sternite VIII see Fig. 28 , with a broad arcuate emargination. Aedoeagus see Fig. 21 , the apex of the ventral blade tapering into a small dorsally recurved hook.

Female: unknown.

Differential diagnosis

By virtue of its transverse, sub-quadrate and densely microsculptate head, impunctate mid-longitudinal line of the pronotum and opaque elytra this new species resembles S. schoedli Rougemont 1996 , to which it runs in my 1996 key to the Celebesian species. The new species differs from S. schoedli in its slightly smaller size, narrower head with less prominent apico-lateral angles and much more densely microsculptate and therefore duller surface, in the more broadly and deeply emarginate male sternite VIII, and in the aedoeagus. Stiliderus agostii n. sp. differs from the only other two known microsculptate species of the brendelli group, S. opacus Rougemont 1996 and S. opacipennis Rougemont 1996 , in its subquadrate, not orbicular head, as described in dichotomy 7 of the 1996 key.

Figures

Figs. 22–31. Stilicoderus and Stiliderus spp., male sternites VI, VII (22), female sternite XIII (23), male sternite VIII (24, 25, 28), female tergite X (26, 27), fore-body (29–31). – 22. Stilicoderus papuanus n.sp. 23. Stilicoderus sp.X. 24. Stilicoderus sarahae n. sp. 25. Stiliderus germanus n. sp. 26. Stiliderus brendellianus n. sp. 27. Stiliderus sp.Z. 28. Stiliderus agostii n.sp. 29. Stiliderus sp.Z. 30. Stiliderus agostii n.sp. 31. Stiliderus rugulosicollis n. sp. – Scales: 0.5 mm (22–28), 3 mm (29–31).

Figs. 11–21. Stilicoderus and Stiliderus spp., aedoeagi in lateral (a) and ventral (b) views. – 11. Stilicoderus lastianus n. sp. 12. Stilicoderus baliemensis n.sp. 13. Stilicoderus aerosoides n.sp. 14. Stilicoderus papuanus n.sp. 15. Stilicoderus continentalis n. sp. 16. Stilicoderus sarahae n.sp. 17. Stiliderus tengah n. sp. 18. Stiliderus germanus n.sp. 19. Stiliderus rugulosicollis n. sp. 20. Stiliderus brendellianus n.sp. 21. Stiliderus agostii n.sp. – Scales: 0.5 mm.