Derelomus ater Marshall, 1950

Derelomus ater Marshall, 1950

Fig. 16 View Fig

Derelomus ater Marshall, 1950: 262 .

Diagnosis

This species can be distinguished by its uniformly black and shiny integument. It is closest to D. brunneus sp. nov., but shows a rostrum less downcurved in lateral view. Body ratios, male genitalia and protibiae also enable to distinguish these species ( Figs 15D View Fig , 16D View Fig ).

Material examined

Lectotype (here designated)

DEMOCRATIC REPUBLIC OF CONGO • ♂; “Holotypus; ater ♂; Mrshl. [red label]” “Récolté dans fl.♂ Phoenix ; reclinata ” “Musée du Congo; Rutshuru [ 1°11′06″ N, 29°27′14″ E]; - VIII-1937; J. Ghesquière; 4823” “R. DET. Y. 5575” “ Derelomus ; ater . Mshl.; Type ♂” “LECTOTYPE ♂; Derelomus ; ater ; Marshall, 1950; Haran des. 2025”; RMCA.

GoogleMaps

Paralectotypes

DEMOCRATIC REPUBLIC OF CONGO • 2 ♂♂, 6 ♀♀; Rutshuru , Rutshuru; 1°11′06″ N, 29°27′14″ E; Aug. 1937; J. Ghesquière coll.; in male inflorescences of Phoenix reclinata ; 4823; RMCA GoogleMaps • 4 ♀♀; same collection data as for preceding; NHMUK GoogleMaps • 1 ♂; same collection data as for preceding; CBGP. GoogleMaps

Redescription ( ♂)

MEASUREMENTS. Body length 2.0– 3.1 mm.

COLOR. Body integument uniformly dark brown or reddish brown, shiny; scape and first funicular segments reddish; dorsum with minute whitish setae, glabrous in appearance.

HEAD. Rostrum slightly longer than pronotum in lateral view, moderately and regularly downcurved; in dorsal view 5.5× as long as wide, integument densely punctate, forming 5 longitudinal carinae from eyes to antennal insertion, covered with minute recumbent and non-contiguous whitish setae oriented transversally; antennae inserted near apical ¼ of length; head capsule coarsely punctate in dorsal view; eyes convex, exceeding lateral curve of head capsule in dorsal view; antennal funicle with first segment 2 × as long as wide, equal in length to 2+3, 3–4 isodiametric, 5–7 transverse.

PRONOTUM. Wider than long (W: L ratio: 1.20), widest near middle of length, slightly narrower there than elytra at humeral angles; sides convex, abruptly converging in apical ¼, apical constriction as wide as width of scape at apex; integument with scarce punctures, space between punctures smooth, shiny, generally larger than diameter of a puncture on dorsum; the minute white setae more visible laterally, about as long as width of punctures.

ELYTRA. Sides subparallel or slightly convex, widest near 3/5 of length (W: L ratio: 0.64); humeri raised; apex rounded, not contiguous; striae with punctures narrower than width of interstriae; interstriae flat, 9 raised into carina; scutellar shield rounded, similar to integument of elytra, glabrous.

ABDOMEN. Underside covered with minute recumbent whitish setae, not contiguous. Stridulatory plate with lines of 4 granules, about ½× as long as median line ( Fig. 16F View Fig ).

LEGS. Profemora moderately thickened near middle of length; protibiae with external margin straight, meso- and metatibiae slightly curved outward in apical half, internal margin of protibiae bisinuate, bearing a comb of elongated golden setae about as long as largest width of protibiae, extending over apical ⅓ ( Fig. 16E View Fig ); meso and metatibiae lacking comb of elongated setae; claws simple.

TERMINALIA. Body of penis elongate (W: L ratio: 0.30), about as long as apodemes; sides straight in dorsal view, widest base, converging moderately and regularly apicad, apex rounded; in lateral view curvature stronger in basal ½ of length, width narrowing apicad from basal ⅓ ( Fig. 16D View Fig ).

Sexual dimorphism

Females can be distinguished from males by the rostrum which is longer in lateral view, distinctly exceeding the length of the pronotum ( Fig. 16C View Fig ) and narrower in dorsal view. The antennae are inserted on the apical 2/5 of the rostrum length, ¼ in males).

Life history

Specimens used to describe this species were collected on male inflorescences of Phoenix reclinata ( Arecaceae ), which probably constitutes the larval host.

Distribution

Derelomus ater is only known from the type locality in the Eastern Democratic Republic of Congo.

Remarks

In the collection housed at RMCA, a specimen from Rutshuru labelled “ Derelomus ater Mshl. ” and bearing a red type label was located. This specimen is designated as the lectotype for Derelomus ater Marshall, 1950 [here designated] and was labelled accordingly. Other specimens of the series were labelled as paralectotypes.