Silva, Sidnei Bortoluzzi Da & Caron, Edilson, 2014, The unique Brazilian species of Polylobus Solier (Coleoptera: Staphylinidae: Aleocharinae) with a checklist of all species of the genus, Zootaxa 3811 (2), pp. 226-238: 227-228

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Polylobus  stigma ( Erichson, 1839)

( Figs 1–7View FIGURES 1 – 4View FIGURES 5 – 7)

Homalota  stigma Erichson, 1839: 120 (original description, type locality: “ Brasilia ”). Atheta  ( Microdota  ) stigma: Bernhauer & Scheerpeltz, 1926: 635 (distribution). Tricolpochila  stigma: Pace, 1987 b: 170 (characters, lectotype designated).

Polylobus  stigma: Pace, 2000: 400 (mention); 496, 498 (characters).

Type material. Homalota  stigma Erichson, 1839. Syntype deposited in ZMHB, female, dissected, body glued on white board; maxila, labium and spermatheca mounted on the first plastic slide [presumably dissected by Pace in 1983], and right protarsus, tergite 8 and segments 9–10 [dissected by the current authors], both imbedded in Canada Balsam; labels: (1) ‘ 5417 ’ [old white label, printed in black]; (2) ‘ stigma ’ [old white label, handwritten]; (3) ‘Typus’ [red label, printed in black]; (4) ‘ stigmusa / stigma (Er.)/det. R. Pace 1983 ’ [white label, 1 st and 2 nd lines handwritten and the 3 rd line printed in black, with the decade of the year handwritten]; (5) ‘ stigma /Er/ Brasil. Gm.’ [green label, handwritten]; (6) ‘Zool. Mus. Berlin’ [yellow label, printed in black]; (7) ‘ SYNTYPUS / Homalota  / stigma Erichson, 1839 / labeled by MNHUB 2013 ’ [red label, printed in black]. Note 1: In the original description Erichson (1839) did not specify how many specimens he studied. We received from ZMHB only one specimen labelled as type, here named syntype. Note 2: Pace (1987 b) published the lectotype designation of Tricolpochila  stigma, however the designation label in the type material is missing. Note 3: we received the type material with labels organized in that sequence.

Redescription. Female. Maximum body length: 3.0 mm; maximum elytra width: 0.9 mm. Body broad; sides subparallel; uniformly light-brown with darker spot on tergite 6; dorsal surface glossy; setigerous pores sparse and more densely on head, pronotum and elytra; pronotum with pubescence directed latero-posteriad; elytra and abdomen with pubescence straight and direct posteriad.

Head as long as wide; eyes about as long as temples; infraorbital carina complete. Antennal article 2 nd slightly shorter than 1 st and longer than 3 rd; article 4 th subquadrate, articles 5–10 transverse and gradually increasing in width toward antennal apex; article 10 th twice as wide as long; article 11 th as long as articles 8–10 combined. Mandibles broad and curved at apex. Maxila with galea extending slightly beyond apex of lacinia ( Fig. 1View FIGURES 1 – 4), galea narrower than lacinia; apical lobe of galea covered with fine and short setae; internal margin of galea with long subapical setae; apical 1 / 3 of lacinia with a row of spines, middle portion covered with numerous setae; maxillary palpus with 4 articles, 2 nd slightly shorter than 3 rd, and 4 th about half length of thepreceeding one. Labium with ligula split into two lobes ( Fig. 2View FIGURES 1 – 4); labial palpus with 3 articles, 1 st the longest and 2 nd the shortest.

Pronotum transverse, 1.5 times as wide as long, broadest at basal half, anterior margin straight, lateral and posterior margin convex; hypomera invisible in lateral view. Prosternum transverse. Elytra slightly broader than pronotum; 1.2 times as long as pronotum; posterior outer corners deeply emarginated. Hind wings fully developed. Mesoventrite process about half length of mesocoxae, acute and sharp at apex, mesocoxae contiguous, mesocoxal cavities weakly or not margined posteriorly; isthmus almost the same length as mesoventrite process; metaventrite process almost not existent. Tarsal formula 5 - 5 - 5; tarsomere 5 the longest ( Fig. 3View FIGURES 1 – 4), as long as 3 rd and 4 th combined.

Abdomen gradually narrowing apically, first four visible terga deeply impressed basally; segment 7 the longest. Tergite 8 sparsely pubescence in posterior half, bearing three prominent setae at each side ( Fig. 5View FIGURES 5 – 7); posterior margin truncate. Sternite 8 sparsely pubescence in posterior half, bearing one prominent setae at each side ( Fig. 6View FIGURES 5 – 7); posterior margin broadly rounded. Tergite 10 slightly emarginated at apex and fused with tergite 9 medially ( Fig. 7View FIGURES 5 – 7). Spermatheca L-shaped ( Fig. 4View FIGURES 1 – 4); subspherical capsule, with slightly invaginated apex.

Male. Unknown.

Distribution. Brazil. In the original description ( Erichson 1839), and on the label of the type material there is not precise information about the locality, only that the material was donated by Germar ( Erichson 1839), presumably Ernst Friedrich Germar.

Bionomics. Unknown.

Taxonomic note. Pace (1987 b: 170) compared Polylobus  stigma with Tricolpochila topaliana ( Scheerpeltz, 1972)  , and in Pace (2000: 496, 498) compared P. s t i gm a with P. valparaisensis Pace, 2000  and P. granulifer Pace, 2000  , respectively. According to Pace, the characters easily separate P. s t i g m a from them are: length of eyes, punctures on elytra and general form of spermatheca. Unfortunately, in this work it was not possible to compare P. stigma with those species.

Following Klimaszewski & Sturm (1991) the genus have galea with sponge-like apical bristles, not seen in P. stigma. The galea of P. stigma has internal margin with long subapical setae, very similar to the species of Stethusa  ( Athetini  ) ( Gusarov 2002, Fig. 12). We also agree with Pace (2000: 400) that Polylobus  is forming a complex group, at least with Tricolpochila Bernhauer, 1908  and Polylobinus Bernhauer, 1908  . We tentatively include Polylobus  stigma in the genus Polylobus  pending further revision of the genus and related genera.













Silva, Sidnei Bortoluzzi Da & Caron, Edilson 2014


Pace 2000: 400


Pace 1987: 170
Bernhauer 1926: 635
Erichson 1839: 120