Derelomus postfasciatus Hesse , 1929

Derelomus postfasciatus Hesse, 1929

Fig. 23 View Fig

Derelomus postfasciatus Hesse, 1929: 527 .

Derelomus postfasciatus – Haran et al. 2022b (phylogenetic relationships); 2023a (life history).

Diagnosis

In the D. ephippiger group, this species can be distinguished by its typical elytral pattern, forming a large and contrasting dark spot beyond the middle of the length on each elytron, sometimes merged in a transverse strip and by the body of the penis which is very elongate with the sides concave. This species looks similar to D. chamaeropis , but in the latter species, the elytra are always uniformly pale brown without pattern. GenBank accession numbers for the corresponding DNA barcodes: ON553425 View Materials –26

Material examined

Lectotype (here designated)

REPUBLIC OF SOUTH AFRICA • ♂; “ Kentani [ Eastern Cape Province, 32°31′05″ S 28°19′30″ E]; 1907; Miss Pegler” “South Africa; Kentani, 1907; Miss Pegler [Alice M. Pegler, south african entomologist and botanist, see Etymology section under Derelomus peglerae ]” “TYPE [red label]” “ Derelomus ; postfasciatus Hesse” “Lectotype ♂; Derelomus ; postfasciatus ; Hesse, 1929; Haran des. 2025”; SAMC.

GoogleMaps

Paralectotypes

REPUBLIC OF SOUTH AFRICA – Eastern Cape Province • 8 ♂♂, 13 ♀♀; Kentani; 32°31′05″ S, 28°19′30″ E; 1907; Pegler coll.; SAM-ENT-4035 ; SAMC GoogleMaps • 10 ♂♂, 7 ♀♀; same collection data as for holotype; NZAC. GoogleMaps

Other material

REPUBLIC OF SOUTH AFRICA – Limpopo Province • 2 ♂♂; Hans Merensky Nature Reserve ; 23°41′42″ S, 30°40′05″ E; 23–25 Jan. 1987; R. Oberprieler coll.; collected on leaves of Phoenix reclinata ; SANC GoogleMaps • 1 ♂, 1 ♀; Nwanedi Provincial Park ; 22°37′34″ S, 30°24′22″ E; 8 Feb. 1994; R. Oberprieler coll.; collected from Phoenix reclinata ; SANC GoogleMaps • 1 ♂; Mmabolela Estate; 22°37′52″ S, 28°16′34″ E; 7 Mar. 1973; Endrödy-Younga coll.; air plankton; E-Y: 18; TMSA. GoogleMaps – Eastern Cape Province • 3 ♂♂, 2 ♀♀; Kentani; 32°31′05″ S, 28°19′30″ E; 1927; Pegler coll.; NHMUK GoogleMaps • 2 ♂♂, 1 ♀; Mbotyi campsite ; 31°27′54″ S, 29°43′48″ E; Dec. 2009; Ş. Procheş coll.; male and female inflorescences of Phoenix sp. ; JHAR07432 ; CBGP. GoogleMaps – Western Cape Province • 1 ♂; 1 spec. (preserved in ethanol); Stellenbosch; 33°55′48″ S, 18°52′30″ E; 18 Jul. 2018; J. Haran coll.; on flowers of Buddleja auriculata Franch. ( Buddlejaceae ); JHAR01180 ; CBGP GoogleMaps • 3 ♂♂; Pringle Bay ; 34°21′00″ S, 18°49′48″ E; 28 Nov. 2019; J. Haran coll.; on male inflorescence of Phoenix reclinata ; JHAR03078-02 ; CBGP GoogleMaps • 1 ♀; Cape colony [exact locality?]; 1910; C.W. Mally; NHMUK.

Redescription ( ♂)

MEASUREMENTS. Body length 2.2–2.8 mm.

COLOR. Body integument pale brown, post-ocular area, apex of rostrum, antennal club and scutellar shield dark brown, each elytron with a dark spot beyond middle of length, usually extending between interstriae 2 and 7, in some specimens forming contiguous transverse dark band between interstriae 9; elytra and pronotum with minute recumbent whitish setae, glabrous in appearance.

HEAD. Rostrum distinctly longer than pronotum in lateral view (1.15 ×), slightly and regularly downcurved; in dorsal view about 6 × as long as wide, integument densely punctate, forming 5 longitudinal carinae; antennae inserted near apical ¼ of length in lateral view; head capsule densely punctate in dorsal view, forehead flat or slightly concave; 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 segments 2–3 together, 2–4 isodiametric, 5–7 transverse.

PRONOTUM. Wider than long (W: L ratio: 1.25), widest near middle of length or in basal ⅓, 0.85 × as wide there as elytra at humeral angles, converging apicad in apical ½, lateral carina forming notch near middle of length; apical constriction deep; integument with punctures rounded, space between punctures smooth, shiny, micropunctate, wider than diameter of punctures in middle, narrower laterally.

METATHORAX. Metanepisterna with recumbent white setae, non-contiguous.

ELYTRA. Longer than wide (W: L ratio: 0.73); sides slightly convex, widest near middle of length; humeri raised; apex jointly rounded; striae with punctures about ⅓–¼ as wide as width of interstriae; interstriae slightly convex; scutellar shield rounded, coated with few small recumbent scales.

ABDOMEN. Underside uniformly pale brown, with minute recumbent whitish setae, not contiguous. Stridulatory plate with lines of 8 granules ⅔ × as long as median line from base, slightly convex. Central sclerotized area wide, transverse, truncate at base ( Fig. 23E View Fig ).

LEGS. Profemora moderately thickened near middle of length; protibiae with external margin straight, internal bisinuate, setae on apical half of internal margin recumbent, at most as long as claws; claws simple.

TERMINALIA. Body of penis elongate (W: L ratio: 0.23), about 2× as long as apodemes; sides concave in dorsal view, widest near base, widening apicad from apical ⅓ and then narrowing from apical 1/5 of length, apex forming a spatula; in lateral view curvature slightly stronger in basal ½ of length, width narrowing regularly from apical 2/5, apex slightly curved upward ( Fig. 23D View Fig ).

Sexual dimorphism

Females can be distinguished from males by the rostrum which is longer (1.3 × as long as pronotum in lateral view, about 7–8× as long as wide in dorsal view), more downcurved and with a shinier integument ( Fig. 23C View Fig ). The antennae are inserted at the apical 2/5 of the rostrum (near the apical ¼ in males).

Life history

Adults are found on the male inflorescences of Phoenix reclinata ( Arecaceae ), which probably constitutes the habitat for larvae. This species is active during the day, sporadically recorded visiting flowers of various bushes. Adults were recorded from July to March.

Distribution

Endemic to the Republic of South Africa in our current knowledge. Recorded from the coastal regions of the Eastern and Western Cape provinces and inland in the Limpopo Province.

Remarks

In the collection housed at SAMC, a male specimen from Kentani ( Republic of South Africa), bearing the red type label and identified as Derelomus postfasciatus by the hand of A.J. Hesse, was located. This specimen is designated as the lectotype for Derelomus postfasciatus Hesse, 1929 [here designated] and was labelled accordingly. The other specimens of this series were labelled as paralectotypes.