Eleusis adusta ( FAUVEL, 1864 )

Irmler, Ulrich, 2017, The Neotropical species of the genus Eleusis LAPORTE, 1835 with description of the new genus Eleusima (Coleoptera: Staphylinidae: Osoriinae), Beiträge Zur Entomologie = Contributions to Entomology 67 (2), pp. 275-318 : 293-294

Eleusis adusta ( FAUVEL, 1864)

Figs 23 A-C, 30D

Isomalus adustus FAUVEL, 1864: 33

Type material examined: male, Holotype: Brazil: Novo

Friburgo ( IRSNB).

Additional material examined: Paraguay: Cazaapá, Hermosa prop. Sosa family, San Rafael Reserve (26°19.15'S, 55°44.55'W), 90 m elev., fermenting tree wound, male, 5.12.2000, leg. Z.H. Falin #PAR1F00116 ( KNHM) ; Brazil: Pará (Belém), Marco da Legua (-48.43, -1.45), without more data male, ( IRSNB) ; Minas Gerais, Barreira de Piquete, Sierra Mantiqueira , 1500 m elev., 2 males, 1 female, Dec. 1957, leg. H. Schubart ( UIC) ; Rio de Janeiro, Teresopolis , male, Dec. 1957, leg. M. Alvarenga ( UIC) ; Rio de Janeiro, male, leg. Squires ( BMNH) ; Cachoeirinha-Una (- 41.20 W, - 12.19S), Bahia, without more data ( NMW) .

Diagnosis: Referring to the few specimens studied, the size and head shape of the species seem to be constant in contrast to those of E. bicolor and E. struyvei . Colouration is similar as in E. bicolor and E. struyvei with black or dark brown head and pronotum and reddish anterior half of elytra. In contrast to those species, the anterior abdominal segments are dark and posterior segments yellow, whereas anterior abdominal segments are lighter in E. bicolor and E. struyvei . It can be additionally differentiated from these two species by the sparser microsculpture and the more continuous punctation of the head as well as the absence of grooves at the anterior angles of the pronotum. Moreover, in ventral aspect the aedeagus is slenderer than that of E. bicolor and E. struyvei .

Description: Length: 5.5 – 6.0 mm. Colouration: head and pronotum black; elytra orange with posterior margin dark brown; abdomen dark brown except posterior two segments orange; legs and antennae dark brown; tarsi yellow.

Head: 0.95 mm long, 1.05 mm wide; temples parallel; approximately twice as long as eyes; posterior angles obtusely narrowed to wide neck; supraocular groove wide; widened posteriad; preocular sides shortly parallel to base of antennae; anterior angles obtuse; continuously narrowed to centre of clypeus; at anterior edge, setiferous puncture in supraocular groove; second one at posterior edge; pair of setiferous punctures at centre of anterior margin; deep and moderately dense punctation; interstices between punctures varying between as wide as diameter of punctures and twice as wide as diameter of punctures; on clypeus, elongate microsculpture deep and dense; on lateral vertex, weaker and sparser; absent on central vertex; dense in supraocular grooves; surface of clypeus and vertex shiny; surface of supraocular groove matt.

Antennae as long as head and half of pronotum combined; first antennomere slightly thicker than following antennomeres; second approximately half as long as first; as long as apical width; third antennomere distinctly longer than second, but slightly shorter than first; following antennomeres slightly increasing in width; tenth approximately quadrate; fifth to eleventh antennomere pubescent; with few longer apical setae.

Pronotum: 0.89 mm long; 1.04 mm wide; in anterior half, sides parallel; in posterior half continuously narrowed to posterior margin; anterior angles shortly rounded to wide anterior margin; without distinct groove at anterior angles; posterior angles obtuse; central part slightly prominent posteriad; deep groove bordering posterior central part margined by sharp ridge; punctation as deep as on head, but slightly sparser; on average, interstices between punctures at least twice as wide as diameter of punctures; remains of elongate microsculpture; denser at posterior grooves than on disc; surface moderately shiny.

Elytra: 1.08 mm long, 1.17 mm wide; slightly widened to posterior angles; posterior angles obtusely rounded; humeral angles obtusely angled, punctation as dense and deep as on pronotum; several coarser punctures at lateral margin; on each side of suture, one setiferous deep puncture in central position; elongate microsculpture weaker, but denser than on pronotum; surface moderately shiny. Abdomen sparsely punctate with transverse row of setiferous punctures on each abdominal segment; transversely striate microsculpture as deep as on elytra; surface moderately shiny.

Aedeagus in lateral view broadly curved; wide apex rounded; stronger sclerotised ventral plate with diagonal striae; with numerous sensillae; slender parameres shorter than central lobe; apical transparent lobe only slightly wider than scape of parameres; few sensillae at apex and on scape; in ventral view, central lobe slender; sides parallel; apex of ventral sclerotised plate deeply emarginate.

Figures

Fig. 18–23: Eleusis platysoma (18), E. bicolor (19), E. struyvei (20), E. fenestrata (21), E. rufula (22), E. adusta (23): aedeagus in lateral (A) and ventral (B) view, antenna (C), head (D), colouration of elytra (E); scale bar A, B: 0.1 mm, C: 0.2 mm, D, E: 1.0 mm.