Derelomus zonatus Marshall, 1950

Derelomus zonatus Marshall, 1950

Fig. 14 View Fig

Derelomus zonatus Marshall, 1950: 263 .

Diagnosis

This species belongs to the D. nigrovariegatus group, characterised by the combination of a glabrous lateral carina on the pronotum, the large body length (generally beyond 3 mm) and the prosternum at least partly dark brown. Within this species group, it can be distinguished by the contrasting transverse dark band on the elytra and the prosternum with dark spots on the pale brown integument. The narrow space between the granules of the stridulatory plate seems diagnostic for this species (although this feature has not been examined for D. nigrovariegatus ).

Material examined

Lectotype (here designated)

DEMOCRATIC REPUBLIC OF CONGO • ♂; “Holotypus; zonatus ♂; Mrshl.[red label]” “Musée du Congo; Rutshuru [ 1°11′06″ N, 29°27′14″ E]; - IV-1937; J. Ghesquière; 3966” “R. DET; AA5575” “Récolté dans; pulpe fr. Phoenix ; reclinata ” “ Derelomus ; zonatus, Mshl. ; TYPE♂” “ LECTOTYPE ♂; Derelomus ; zonatus ; Marshall, 1950; Haran des. 2025”; RMCA. GoogleMaps

Paralectotypes

DEMOCRATIC REPUBLIC OF CONGO • 1 ♀; Rutshuru; 1°11′06″ N, 29°27′14″ E; Apr. 1937; J. Ghesquière coll.; sampled in fruit pulp of Phoenix reclinata ; 3966; RMCA • 1 ♂, 1 ♀; same collection data as for preceding; NHMUK. GoogleMaps

GoogleMaps

Other material

UGANDA • 1 ♀; Kawanda; 0°25′30″ N, 32°32′24″ E; 14 Apr. 1943; T.H.C. Taylor; NHMUK. GoogleMaps

Redescription ( ♂)

MEASUREMENTS. Body length 3.3 mm.

COLOR. Body integument pale brown, head capsule and rostrum, antennae and sometimes apex of femora brown; dark pattern on dorsum generally forming spots on sides of pronotum, a large transverse band near middle of length of elytra as well as at base and apex of even interstriae; dorsum with minute whitish setae, not contiguous, forming 2–3 rows on each interstria.

HEAD. Rostrum slightly longer than pronotum in lateral view, moderately and regularly downcurved; in dorsal view 3.5 × as long as wide, integument densely punctate, forming 5 longitudinal carinae from eyes to antennal insertion, median carina more raised than others and split in two before 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 moderately lateral curve of head capsule in dorsal view; antennal funicle with first segment 2× as long as wide, equal in length to 2+3, 3–7 transverse.

PRONOTUM. Wider than long (W: L ratio: 1.28), widest near basal ⅓ of length, slightly narrower there than elytra at humeral angles (0.8 ×); sides convex, with distinct constriction slightly beyond middle of length, abruptly converging in apical ¼, apical constriction as wide as width of scape at apex; integument densely punctate, space between punctures irregular, dull, as wide as or narrower than diameter of a puncture on dorsum; white setae shorter than diameter of punctures.

ELYTRA. Sides slightly convex, widest near middle of length (W: L ratio: 0.70); humeri raised; apex rounded, not contiguous; striae with punctures 2× narrower than width of interstriae; interstriae slightly convex, 5 more so, 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 14–17 granules, about ½× as long as median line, not reaching apex of median area ( Fig. 14F View Fig ), space between granules as wide as diameter of a granule.

LEGS. Profemora 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 comb of elongated golden setae about as long as largest width of protibiae, extending over apical half ( Fig. 14E View Fig ); meso and metatibiae lacking comb of elongated setae; claws simple.

TERMINALIA. Body of penis elongate (W: L ratio: 0.25), about 3× as long as apodemes; sides straight in dorsal view, widest near middle of length, converging apicad from apical 2/5, apex short acuminate spatula; in lateral view curvature stronger in basal ½ of length, width narrowing apicad from middle of length, apex bisinuate ( Fig. 14D 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. 14C View Fig ) and narrower in dorsal view. The antennae are inserted slightly before the apical ¼ of the rostrum length.

Life history

Adults of this species were found in fruit pulp of Phoenix reclinata . This lifestyle is unusual for species of Derelomus , there is no clear indication that this palm is the host for larvae in this species. Adults were collected in April.

Distribution

In our current knowledge, this species is restricted to the Eastern part of the Democratic Republic of Congo and to Uganda.

Remarks

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