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

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Pseudastenus plaumanni ( Bierig, 1939 )


Pseudastenus plaumanni ( Bierig, 1939)  

Figs. 1–35 View FIGURES 1–11 View FIGURES 12–20 View FIGURES 21–29 View FIGURES 30–35 , 37, 39 View FIGURES 36–39. 36 , 46–47 View FIGURES 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 View FIGURES 36–39. 36 ). 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 View FIGURES 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 View FIGURES 46–47 ).

Taxonomic notes. The type specimen of P. plaumanni   , including aedeagus, was in bad conditions. Figure 46 View FIGURES 46–47 shows the aedeagus of the lectotype, whereas Fig. 48 View FIGURES 48–54 shows the aedeagus of a male collected near the type locality. In Figs. 46 and 47 View FIGURES 46–47 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.


Field Museum of Natural History


Sao Paulo, Museu de Zoologia da Universidade de Sao Paulo


Universidade Federal do Parana, Colecao de Entomologia Pe. Jesus Santiago Moure














Pseudastenus plaumanni ( Bierig, 1939 )

Busanello, Dilson G. C., Irmler, Ulrich & Caron, Edilson 2020

Xenaster plaumanni

Newton, A. F. 2017: 19
Bierig, A. 1939: 179