Glyptoma cognatum SHARP, 1887

Irmler, Ulrich, 2015, The neotropical genus Glyptoma ERICHSON, 1839 with descriptions of new species and a key to the species (Coleoptera: Staphylinidae: Osoriinae), Beiträge Zur Entomologie = Contributions to Entomology 65 (2), pp. 297-325 : 311-313

Glyptoma cognatum SHARP, 1887

( Figs 16A, B , 22D )

Glyptoma cognatum SHARP, 1887: 724

Type material examined: Guatemala: 1 male, 1 female syntypes: El Reposo, leg. C. Champion ( BMNH) .

Further material examined: Panama: 1 male, Canal Zone , Albrook Forest Site, collected by black light (ground), 23.– 24.5.1968, leg. R. Hutton ( AMNH) ; 1 female, same location, 100 ft. elev., collected by black light, 16.5.1968, leg. R. Hutton ( AMNH) ; French Guiana: 1 male, 2 females, Saül , under bark, March–April 1999, leg. A. Berkov ( AMNH, UIC) .

Diagnosis: The three species G. cognatum , G. denieri , and G. klimschi are very similar in size and shape of the aedeagus. G. cognatum can be differentiated from the two other species by the intermediate size from the slightly larger G. denieri and the slightly smaller G. klimschi . Regarding the microsculpture of the head and pronotum as well as both the thin apical lobe and few sensillae of the aedeagus, it resembles G. denieri . However, the microsculpture of G. cognatum is weaker than in G. denieri and the number of punctures in the posterior half of the elytra is lower. In contrast to G. denieri , the apex of the aedeagus of G. cognatum is curved pointing ventrad, whereas it is more or less straight in G. denieri .

Description: Length: 2.1–2.2 mm. Colouration: Dark brown; elytra lighter red; legs still lighter, yellowish.

Head: 0.27 mm long, 0.40 mm wide; eyes slightly prominent; nearly twice as long as temples; temples narrowed to neck in short strongly convex curve; sides in front of eyes parallel up to base of antennae; parallel part as long as length of eyes; at base of antennae abruptly narrowed to anterior edge of clypeus in nearly rectangular angle; anterior edge of clypeus slightly shorter than distance between base of antennae; setiferous punctures deep and moderately dense; interstices between punctures ranging between twice and three times as wide as diameter of punctures; close to neck, punctation denser; with weak irregular microsculpture; partly longitudinally striate; partly transversely striate; surface moderately shiny.

Antennae as long as head and pronotum combined; all antennomeres nearly equally wide; second antennomere nearly twice as wide as long; third to fifth antennomere approximately 2.5 to 3 times as wide as long; tenth antennomere again twice as wide as long; second to tenth antennomere with long yellow setae; on average, setae approximately as long as half of width of antennomeres.

Pronotum: 0.29 mm long 0.35 mm wide; widest at anterior third; narrowed to anterior angles in short convex curve; narrowed to posterior angles in long, slightly concave curve; anterior and posterior angles obtuse; front edge slightly prominent; posterior edge as wide as neck; setiferous punctures large, but size irregular; partly coriaceous; on average, interstices between punctures mostly restricted to very narrow ridges; at posterior angles with irregular elongate impression; narrow midline impunctate; disc bordered by indistinct, irregularly sinuate carinae; insertion of setae partly centric, partly eccentric; microsculpture weak; longitudinally striate; surface shiny. Elytra: 0.48 mm long, 0.45 mm wide; sides smoothly rounded; nearly parallel; shoulders distinct; shortly rounded to emarginate anterior edge; suture line formed by densely coriaceous small punctures; continued to posterior margin; discal carina distinct; lateral carina absent or only partly developed; discal carina margined at inner and outer edge by longitudinal row of elongate setiferous punctures; in anterior half on area between suture line and discal carina, several setiferous punctures; in posterior half impunctate; laterad to discal carina three longitudinal rows of setiferous punctures; extremely weak microsculpture; longitudinally striate; surface shiny.

Abdomen on segments III to VI with two transverse irregular rows of large setiferous punctures; posterior half of segments III to VI with impunctate area; without microsculpture; surface shiny.

Aedeagus angulate between basal and apical lobe; angle obtuse; apical lobe narrow ending in acute apex; apex shortly curved; pointing ventrad; very few small sensillae at base of apical lobe; paramere reaching end of basal third of apical lobe.

Figures

Figs 22: Fore body of Glyptoma nitidum (A), G. obscuricollis (B), G. nitens (C), G. cognatum (D), G. sanctaecatharinae (E), G. klimschi (F); scale bar 0.5 mm.

Figs 13–17: Aedeagus (A), antenna (B) and microsculpture of head (C) ofGlyptoma nitidum (13), G. obscuricolle (14), G. nitens (15), G. cognatum (16), G. denieri (17); scale bar: 0.1 mm.