Antimerus Fauvel, 1878

Antimerus Fauvel View in CoL , monotypic.

Diagnosis

This subtribe can be recognized unambiguously among all other Staphylinini by the unique anterior transverse basal lines of the abdominal tergites, which extend posteriad to encompass the spiracles ( Fig. 2E). Other unusual characters of Antimerus in Staphylinini include entirely (or nearly) toothless mandibles, broad areas of tenent setae on all tarsomeres, protergal glands absent and the fusion of the ventral paired copulatory sclerites of the internal sac into a plate-like structure (least fused in Antimerus jamesrodmani Solodovnikov & Newton ).

Description

Large to very large (13–20 mm), robust, Staphylininalike rove beetles, ranging from brightly metallic green, brass or blue to boldly marked with patches of pubescence. Dorsal forebody with microsculpture ranging from a patchwork of microsculptured fragments, whirled in differing directions, to meshed or transverse but non-concentric waves. Antennae non-geniculate; antennomeres 1–4 lacking tomentose pubescence; antennomeres 1–3 lacking dense setae; apical antennomere lacking broad microsetal field. Head with frontoclypeal puncture present; dorsal basal ridge absent; labrum short, transverse and narrowly divided at middle; gular sutures strongly converging toward base of head but not entirely fusing. Labial palpi without dense brushes on second segment. Mandibles curved, either edentate or with very weak tooth in basal half. Prothorax with membranous postcoxal process, either interrupted at base by inferior line or not; basisternum triangular, lateral arms narrowed subapically; basisternum with pair of macrosetae; pronotum and prosternum not fused in procoxal cavity. Mesoscutellum punctate; posterior scutellar ridge present; subbasal elytral ridge not forming scutellar collar, present as a fragment only; humerus with row of spines. Elytral epipleuron without row of setae in impressed punctures. Profemur without apical row of lateroventral spines. Tarsomeres 2–5 of all legs trapezoid and flattened, setose on disc. Metacoxae without transverse carina. All tarsi with five segments and with pair of empodial setae; setae not distinctly longer on mid- and hindleg compared with foreleg. Wings with veins CuA and MP4 completely separate; MP3 present. Protergal glands absent. Abdominal tergites without accessory basal lines; anterior transverse basal lines extended posteriad to entirely encompass spiracles ( Fig. 2E), without true posterior transverse basal lines. Abdominal sternite III with basal transverse carina obtuse.

Male: Sternite VIII with distinct emargination; parameres fused, with peg setae; base of paramere visible and not fused to median lobe; aedeagus with internal sac bearing ventral paired copulatory sclerites fused into plate-like structure; two-pronged copulatory piece and external copulatory plate absent.

Distribution

Antimerus is known only from subtropical wet forests in northeastern and southeastern Australia ( Solodovnikov & Newton, 2010). The authors stated that this disjunction is likely to be real, corresponding to the distribution of suitably moist forests in eastern Australia.