Eleusis castanea, Irmler, 2017

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 : 280-281

Eleusis castanea spec. nov.

urn:lsid:zoobank.org:act:3121AA37-99A7-4839-9172-A2A98F9E5372

Figs 11 A-C, 29C

Type material: male, Holotype: Colombia: Cundinamarca, PNN Chingaza Bosque Palacio (73°45'W, 4°31'N), 2930 m elevation, Malaise trap, 5.- 17.1.2001, leg. L. Cifuentes, L., #M 1222 ( KNHM).

Diagnosis: E. castanea belongs to a group of four similar species with reddish elytra, which also includes E. ecuadoriensis , E. genieri , and E. rufipennis . E. castanea is one of the largest species of the E. humilis-group. The differences to E. ecuadoriensis are listed there. Compared to E. genieri and E. rufipennis , E. castanea has unicoloured dark reddish elytra and is larger than those two species. In contrast to E. castanea , E. genieri and E. rufipennis have partly darkened elytra, either at the base or at the apex. However, punctation, microsculpture and overall shape is very similar to these species. It can be easily differentiated from the related E. genieri and E. rufipennis by the thick aedeagus with the thick central prominence.

Description: Length: 5.5 mm. Colouration: head and pronotum black; abdomen dark brown; elytra chestnutreddish; legs and antennae light brown.

Head: 0.80 mm long; 0.80 mm wide; eyes not prominent; half as long as temples; temples shortly narrowed to distinct neck; sides in front of eyes shortly parallel to base of antennae; anterior margin of clypeus sinuate; prominent central part as wide as each lateral part; supraocular groove from anterior edge of eyes to beginning of neck; posterior part slightly wider than anterior part; pair of central impressions at posterior margin of clypeus; distance to lateral margin four times as wide as distance between impressions; punctation moderately deep and dense; on average, interstices twice as wide as diameter of punctures; punctation equally dense on vertex and clypeus; only small anterior stripe with weak and sparse punctation; two large setiferous punctures on each side of prominent part of clypeus; dense microsculpture moderately deep; meshes longitudinal; on anterior part of clypeus weaker and transverse; surface at anterior edge of clypeus shiny; at posterior part of clypeus and vertex moderately matt.

Antennae as long as head and half of pronotum combined; fist antennomere slightly longer and thicker than following antennomeres; second to sixth antennomeres longer than wide; second antennomere nearly half as long as first; third nearly as long as first; following antennomeres increasing in width and decreasing in length; fourth antennomere slightly longer than wide; tenth antennomere slightly wider than long; third to eleventh antennomere pubescent and with long apical setae.

Pronotum: 0.58 mm long, 0.79 mm wide; widest in anterior half; smoothly rounded to anterior angles; strongly narrowed to posterior angles; posterior margin slightly less than half as wide as anterior margin; shortly behind middle, sides denticulate; punctation as regular, deep and dense as on vertex; four large setiferous punctures at anterior margin on each side; along lateral margin few more large setiferous punctures; microsculpture similarly deep and dense as on vertex; in central part at anterior margin transverse; on disc longitudinal and at anterior angles diagonal; surface moderately matt.

Elytra: 1.01 mm long, 0.89 mm wide; sides slightly widened to posterior angles; humeral angles shortly rounded; punctation similarly dense and deep as on pronotum; punctures slightly more elongate; one large setiferous puncture in centre on each side of suture; few large setiferous punctures at base, posterior, and lateral margin; microsculpture longitudinally elongate; as dense and deep as on pronotum; surface moderately matt.

Abdomen with similar punctation as on elytra, but each segment with transverse rows of large setiferous punctures; microsculpture transversely striate; punctation similarly dense and deep as on elytra.

Aedeagus thick; apex obtusely rounded; triangular prominence at central part of central lobe large with numerous sensillae; adjacent to triangular prominence numerous sensillae; paramera nearly as long as central lobe; apical part widened to rectangular transparent lobe; transparent lobe at outer angles with short setae; several small sensillae at apical margin; few larger sensillae at base.

Etymology: The species name derived from the Latin word castaneus which means chestnut-brown and refers to the reddish-brown elytra.

Figures

Fig. 7–12: Eleusis fauveli (7), E. hondurana (8), E. nigrita (9), E. indica (10), E. castanea (11), E. genieri (12); aedeagus in lateral (A)