Pseudastenus plaumanni ( Bierig, 1939 )

Busanello, Dilson G. C., Irmler, Ulrich & Caron, Edilson, 2020, Revision of Pseudastenus Bernhauer, synonym with Xenasterides Newton and six new species (Coleoptera, Staphylinidae, Paederinae), Zootaxa 4755 (1), pp. 139-154 : 142-145

Pseudastenus plaumanni ( Bierig, 1939)

Figs. 1–35 , 37, 39 , 46–47

Xenaster plaumanni Bierig, 1939: 179 (original description, type locality: “ Brasil, Nova Teutonia”). Xenasterides plaumanni: Newton, 2017: 19 (generic name replaced).

Type material examined. Lectotype herein designated ( Fig. 37, 39 ). Male, dissected, deposited in FMNH, Brasil, Nova Teutonia. In the original description Bierig (1939) did not specify the number of specimens but mentioned that the male was unknown. The type deposited in FMNH is a male and it was labelled as lectotype.

Additional materia l. PERU: 1 specimen from Huanuco ( UIC) ; BRAZIL: 2 specimens from Goiás ( MZSP) , 2 specimens from Distrito Federal ( MZSP) , 1 specimen from Paraná ( DZUP) , 37 specimens from Santa Catarina ( FMNH) ; ARGENTINA: 6 specimens from Missiones ( FMNH) , 10 specimens from Chaco ( FMNH) .

Diagnosis. P. plaumanni belongs to the species group with developed hind wings and elytra longer than wide. Within this species group, it resembles P. latus in coloration and length of eyes. However, in P. plaumanni the apical sclerites of the aedeagus are entirely narrow and S-shaped ( Figs. 46, 47 ).

Description. Body length: 3.38 mm. Coloration: head, pronotum and appendices yellowish brown, head slightly darker and with lighter V-shaped pattern on head in some specimens; basal half of elytra dark brown; apical half yellowish brown; abdomen dark brown, slightly darker than basal half of elytra. Head 0.45 mm long, 0.51 mm wide; eyes slightly prominent; between 0.26 and 0.29 times as long as total length of head; between 0.52 and 0.63 times as long as postocular length; approximately parallel; posterior margin straight; depressed on central vertex in front of neck. Pronotum 0.44 mm long, 0.50 mm wide; widest close to anterior angles; anterior margin slightly curved; posterior margin straight; sides converging posteriad. Elytra 0.53 mm long, 0.50 mm wide; conspicuously longer than pronotum, but slightly narrower; sides slightly convexly curved; widest in the middle; humeral angles rounded and obtuse, but conspicuously developed; hind wings developed; posterior angles nearly rectangular; posterior margin emarginate; suture 0.86 times as long as lateral side; microtuberculate punctation larger than on head and pronotum; with yellow pubescence pointing posteriad, longer than head and pronotum; posterior edge with fringe of sparse robust setae. Abdomen with dense punctation; with yellow pubescence pointing posteriad; pubescence conspicuously longer than on the rest of body. Aedeagus elongate; 0.55 mm long; near 4.25 times as long as wide; parameres indistinguishable; conspicuous basal sclerite; barely S-shaped apical sclerites, 0.11 mm long; ejaculatory duct with two trifurcate sclerites ( Figs. 46, 47 ).

Taxonomic notes. The type specimen of P. plaumanni , including aedeagus, was in bad conditions. Figure 46 shows the aedeagus of the lectotype, whereas Fig. 48 shows the aedeagus of a male collected near the type locality. In Figs. 46 and 47 the S-shaped apical sclerites “b” is considered as diagnostic character for P. plaumanni .

Geographical records. Pseudastenus plaumanni is known from Brazil (north of Goiás, Distrito Federal, Paraná and Santa Catarina), from Argentina (Chaco and Missiones), and from Peru (Huanuco).

Biological notes. Specimens of Pseudastenus plaummani were collected in leaf litter and decaying wood.

Figures

FIGURES 1–11. Scanning Electron Microscopy of Pseudastenus plaumanni. 1. Head, dorsal view; 2. Antenna; 3.Antennomere 9; 4. Glandular pore, antennomere 10; 5. Antennomere 10; 6. Glandular pore, antennomere 9; 7. Antennomere 11, arrow indicates glandular pores; 8. Labrum, dorsal view; 9. Mandible, dorsal view; 10. Maxillary palpus, ventral view; 11. Maxillary palpomere 4.

FIGURES 12–20. Scanning Electron Microscopy of Pseudastenus plaumanni. 12. Labium, ventral view; 13. Detail of glossa, lateral lobe, ventral view; 14. Labium, dorsal view; 15. Pronotum, dorsal view; 16. Pronotum, ventral view; 17. Detail of labial palpomere 3, dorsal view; 18. Elytron, dorsal view; 19. Meso and metaventrite, ventral view; 20. Abdominal sternites I–III.

FIGURES 21–29. Pseudastenus plaumanni. 21. Labrum, dorsal view; 22. Mandibles, dorsal view; 23. Maxilla, ventral view; 24. Tergites I–III, dorsal view; 25. Tergite VI, dorsal view; 26. Tergite VII, lateral view; 27. Foreleg, external view; 28. Tergite VIII, dorsal view; 29. Sternite VIII, dorsal view. Scale bars: 0.2 mm.

FIGURES 30–35. Pseudastenus plaumanni. 30. Tergite IX, male, dorsal view; 31. Sternite IX, male, ventral view; 32. Tergite X, male, dorsal view; 33. Tergite IX, female, dorsal view; 34. Hemisternite IX, female, ventral view; 35. Tergite X, female, dorsal view. Scale bars: 0.2 mm.

FIGURES 36–39. 36. Pseudastenus barretoi, lectotype, dorsal view (FMNH); 37. P. plaumanni, lectotype, dorsal view (FMNH); 38. Labels from the lectotype of P. barretoi (FMNH); 39. Labels from the lectotype of P. plaumanni (FMNH). Scale bars: 2 mm.

FIGURES 46–47. Aedeagus of Pseudastenus plaumanni. 46. Dissected from the lectotype (FMNH), dorsal view. 47. Dissected from a specimen collected in the type locality, dorsal and lateral view, respectively. Details: a, basal sclerite; b, apical sclerite; c, basal sclerite of the ejaculatory duct; d, apical sclerite of the ejaculatory duct. Scale bars: 0.2mm.

FIGURES 48–54. Aedeagus of Pseudastenus, dorsal and lateral view, respectively, figures 51–54 including microscopic detail of basal slerites. 48. P. ribeirocostae sp. nov.; 49. P. ferrugineus sp. nov.; 50. P. latus sp. nov.; 51. P. barretoi; 52. P. oculatus sp. nov.; 53. P. amazonicus sp. nov.; 54. P. schubarti sp. nov. Scale bar: 0.3 mm.