Derelomus abyssinicus Hustache, 1936

Derelomus abyssinicus Hustache, 1936

Fig. 5 View Fig

Derelomus abyssinicus Hustache, 1936: 486 .

Diagnosis

Derelomus abyssinicus can be distinguished by the combination of simple claws, a single transverse dark band on the elytra (rarely two, in 2% of specimens examined) and the lateral carina on the pronotum covered with whitish scales. Within the D. signatus group, this shows the straightest rostrum in lateral view ( Fig. 5B–C View Fig ).

Material examined

Lectotype (here designated)

ETHIOPIA • ♂; “TYPE[red label]” “ Abyssinia; Doukham [Dukem, 8°48′48″ N 38°54′48″ E]; 6,500 to 7000 ft.; 18.x.1926; Dr. H. Scott.” “From flowers; of Mimosa ” “ Derelomus ; abyssinicus ; m.[me]; Hustache det.” “Lectotype ♂; Derelomu s abyssinicus ; Hustache, 1936; Haran 2025”; NHMUK.

GoogleMaps

Paralectotypes

ETHIOPIA • 5 ♂♂, 11 ♀♀; Dukem; 8°48′48″ N, 38°54′48″ E; 18 Oct. 1926; H. Scott leg.; flowers of Mimosa ; NHMUK GoogleMaps • 1 ♂, 1 ♀; same collection data as for preceding; CBGP GoogleMaps • 1 ♂, 2 ♀♀; Mulu, above Muger Valley ; 9°17′06″ N, 40°50′28″ E; 18–23 Nov. 1926; H. Scott coll.; circa 8000 ft; NHMUK. GoogleMaps

Other material

KENYA • 1 ♀; Chyulu Hills ; 2°32′46″ S, 37°50′31″ E; Jun. 1938; alt. 5600 ft.; NHMUK GoogleMaps • 1 ♂; Nairobi ; 1°20′02″ S, 36°47′34″ E; Jan. 1938; A.F.J. Gedye coll.; NHMUK GoogleMaps • 4 ♂, 1 ♀; 90 km from Nairobi (no precise locality); 22 Mar. 1990; D. Hongo coll.; adults collected on Vachellia hockii ; NHMUK • 1 ♀; 90 km from Nairobi (no precise locality); 26 Mar. 1990; D. Hongo coll.; adults collected on Vachellia seyal ; NHMUK • 1 ♀; 10 km from Rumuruti; 0°16′19″ N, 36°29′42″ E; 12 Apr. 1990; D. Hongo coll.; adults collected on flowers of Vachellia hockii ; NHMUK GoogleMaps • 1 ♂; Marich Pass; 1°31′38″ N, 35°25′45″ E; 29 Dec. 1986; Vachellia nilotica ssp. indica (= Vachellia nilotica (L.) P.J.H. Hurter & Mabb.); NHMUK GoogleMaps • 1 ♂; Sultan Hamud, Emali Range ; 2°01′08″ S, 37°22′19″ E; Mar. 1940; NHMUK. GoogleMaps

RWANDA • 1 ♂; Southern Province, Huye District, Kinazi; 2°24′43″ S, 29°47′10″ E; 5–8 Jan. 1953; P. Basilewsky coll.; 1600 m a.s.l.; RMCA. GoogleMaps

TANZANIA • 2 ♂♂, 3 ♀♀; Ukerewe Island; 2°02′36″ S, 33°00′18″ E; P.A. Conrade coll.; NHMUK. GoogleMaps

UGANDA • 1 ♂, 2 ♀♀; Kibalinga area ; 0°30′47″ N, 31°17′13″ E; Jan. 1909; Ch. Alluaud coll.; MNHN GoogleMaps • 1 ♂; Uganda central; 0°22′36.6″ N, 32°22′36.2″ E; Jan. 1909; C. Alluaud coll.; MNHN. GoogleMaps

Redescription ( ♂)

MEASUREMENTS. Body length 2.5–3.0 mm.

COLOR. Body integument pale brown, elytra with curved transverse dark bands from level of metafemora to middle of length of suture; vestiture of dorsum made of minute white setae.

HEAD. Rostrum slightly longer than pronotum in lateral view, slightly downcurved; in dorsal view 4 × as long as wide, integument densely punctate, covered with short suberect whitish setae oriented transversally; antennae inserted at apical ⅓ of length; head capsule densely punctate in dorsal view, with suberect whitish scales a bit more condensed near eyes; eyes convex, exceeding lateral curve of head capsule in dorsal view; antennal funicle with first segment 1.5 × as long as wide, slightly longer than segments 2–3 together, 2 longer than wide, 3–7 transverse.

PRONOTUM. Moderately wider than long (W: L ratio: 1.18), widest near base, 0.75 × as wide there as elytra at humeral angles, lateral carina almost straight, converging apicad; apical constriction shallow; integument with large circular punctures, space between punctures dull, narrower than diameter of punctures; each puncture bearing distinct whitish seta in centre, setiform scales more densely condensed along lateral carinae.

METATHORAX. Metanepisterna with scarce, non-contiguous scales.

ELYTRA. Elongate (W:L ratio: 0.60); sides slightly convex, widest near middle of length; humeri raised; apex non-joined; striae with punctures as wide as or slightly narrower than interstriae; interstriae slightly convex, odd interstriae a bit more raised; scutellar shield rounded, dark brown, glabrous.

ABDOMEN. Underside covered with minute recumbent whitish setae, not contiguous. Stridulatory plate with lines of 5–6 granules, as long as median line; central sclerotized area short, rounded at apex.

LEGS. Profemora thickened near middle of length; protibiae with external margin straight, internal slightly bisinuate; claws simple.

TERMINALIA. Body of penis elongate (W: L ratio: 0.20), about 10× as long as apodemes; sides widest near apex widening from base to apex in dorsal view, apex acuminate; in lateral view curvature stronger in basal ½ of length, width widening regularly from base to apex; apex acute, slightly curved upward ( Fig. 5D View Fig ).

Sexual dimorphism

Females can be distinguished from males by the rostrum which is distinctly longer than pronotum in lateral view ( Fig. 5C View Fig ).

Life history

Adults were collected on Vachellia hockii , V. seyal and unidentified species of Vachellia . Adults were collected almost all year round (January, March, April, June, October, November and December).

Distribution

Ethiopia, Kenya, Rwanda, Tanzania and Uganda.

Remarks

In the collection housed at NHMUK, eight specimens corresponding in all respects to the material listed in the original description of D. abyssinicus ( Abyssinia, Doukham, 1926) were located. As no specific specimen was designed in the description as holotype, the male specimen bearing a red type label was designated as the lectotype for this species [here designated] and was rellabeled accordingly. The other specimens from the series were labelled as paralectotypes. This species in its current concept shows a significant degree of variability, with males from Rwanda (Kinazi) and Uganda (Kibalinga area) exhibiting a much shorter rostrum and more robust antennae than the lectotype. In the original description, Hustache also reported a color and size variation in specimens from Mulu compared to those from Duken ( Ethiopia). After examination of the series, especially the male genitalia and stridulatory plate, no stable and significant differences were observed and all the specimens are therefore left under the name D. abyssinicus pending further investigation. A single female specimen from Mulu with a very divergent phenotype (different color pattern, rostrum strongly downcurved) was excluded from the paralectotype series and labelled as Derelomus sp. (NHMUK).