Polylobus
Creators: name: Silva, Sidnei Bortoluzzi Da
name: Caron, Edilson
Publisher: name: Zenodo
Year: 2014
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Staphylinidae
Polylobus

description: Polylobus stigma (Erichson, 1839)
(Figs 1–7)
Homalota stigma Erichson, 1839: 120 (original description, type locality: “ Brasilia ”). Atheta (Microdota) stigma: Bernhauer & Scheerpeltz, 1926: 635 (distribution). Tricolpochila stigma: Pace, 1987b: 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, 1st and 2nd lines handwritten and the 3rd 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 (1987b) 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 2nd slightly shorter than 1st and longer than 3rd; article 4th subquadrate, articles 5–10 transverse and gradually increasing in width toward antennal apex; article 10th twice as wide as long; article 11th as long as articles 8–10 combined. Mandibles broad and curved at apex. Maxila with galea extending slightly beyond apex of lacinia (Fig. 1), 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, 2nd slightly shorter than 3rd, and 4th about half length of thepreceeding one. Labium with ligula split into two lobes (Fig. 2); labial palpus with 3 articles, 1st the longest and 2nd 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. 3), as long as 3rd and 4th 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. 5); posterior margin truncate. Sternite 8 sparsely pubescence in posterior half, bearing one prominent setae at each side (Fig. 6); posterior margin broadly rounded. Tergite 10 slightly emarginated at apex and fused with tergite 9 medially (Fig. 7). Spermatheca L-shaped (Fig. 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 (1987b: 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.
description: Published as part of 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, pp. 226-238 in Zootaxa 3811 (2) on pages 227-228, DOI: 10.11646/zootaxa.3811.2.4, http://zenodo.org/record/225883