Derelomus ephippiger Gyllenhal, 1836

Derelomus ephippiger Gyllenhal, 1836

Fig. 32 View Fig

Derelomus ephippiger Gyllenhal, 1836: 629 .

Derelomus auberti Hustache, 1932: 68 . Syn. nov.

Diagnosis

In the D. ephippiger group, this species can be distinguished by the combination of a square dark spot at the base of the elytra between interstriae 1–4, the club similar in color to the funicle and the rostrum at most as long as the pronotum in lateral view ( Fig. 32B–C View Fig ). It is closest to D. discus sp. nov. and D. costiger , but in the latter species, the integument of the elytra is uniformly pale brown in males and the rostrum has a distinct size and curvature ( Figs 30C View Fig , 31B View Fig ). The body of the penis and the stridulatory plate are diagnostic in all these species.

Material examined

Lectotypes

COUNTRY(?) • ♂; “Typus [red label]” “♂” “Barbaria? [ Northern coast of Africa, from Morocco to Lybia , see discussion in the Remarks section]; Quensel [Conrad Quensel, Swedish entomologist]” “NHRS-JLKB000073801” “ LECTOTYPE ♂; Derelomus ; ephippiger ; Gyllenhal, 1836; Des. Haran, 2025”; NHRS.

GABON • ♀; “Museum Paris; Gabon; Collection Léon Fairmaire; 1906” “ LECTOTYPE; Derelomus ; auberti ; Hust. 1932; Haran des. 2025” “ Derelomus ; ephippiger ; Gyllenhal, 1836; Haran det. 2025”; MNHN.

Paralectotypes

COUNTRY (?) • 1 ♂, 1 ♀; data as for lectotype; NHRS.

GABON • 1 ♀; same collection data as for lectotype of D. auberti ; MNHN.

Other material

NIGERIA • 1 ♂; Jos; 9°54′00.0″ N, 8°51′10.8″ E; 13 Oct. 1955; J. Bechyně coll.; expedition Museum G. Frey Nigeria-Cameroon; NHRS. GoogleMaps

SENEGAL • 1 ♀; Kayar; 14°54′57.6″ N, 17°07′08.4″ W; 8 Apr. 1951; Villiers coll.; MNHN GoogleMaps • 1 ♂, 1 ♀; same collection data as for preceding; NHMUK.

Redescription ( ♂)

MEASUREMENTS. Body length 2.8–3.0 mm.

COLOR. Body integument pale brown, pronotum and head usually slightly darker than the rest of body, basal 3/5 of interstriae 1–4 dark brown, forming dark rectangle contrasting with rest of elytra; dorsum with minute recumbent whitish setae, glabrous in appearance.

HEAD. Rostrum as long as pronotum in lateral view, slightly and regularly downcurved; in dorsal view about 3× 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; eyes convex, exceeding lateral curve of head capsule in dorsal view; antennal funicle with first segment 2× as long as wide, as long as segments 2–3 together, 3–7 transverse.

PRONOTUM. Wider than long (W: L ratio: 1.52), widest near base, a little narrower there than elytra at humeral angles (0.85×), side slightly rounded, converging apicad, forming notch and blunt tooth near middle of length; apical constriction distinct, about as deep as width of scape in middle of length; integument with punctures rounded, space between punctures rough, shiny, micropunctate, wider or narrower than diameter of punctures in middle, narrower laterally.

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

ELYTRA. A little longer than wide (W: L ratio: 0.92); sides convex, widest near middle of length; humeri raised; apex rounded, notched or jointed at level of suture; striae with punctures about ¼ as wide as width of interstriae; interstriae flat, 5 raised into carina; scutellar shield rounded, concolorous, coated with small recumbent scales not concealing integument.

ABDOMEN. Underside uniformly pale brown, with minute recumbent whitish setae, not contiguous. Stridulatory plate with lines of 4 granules about 2/5× as long as median line from base, space between granules 1–2× as wide as diameter of a granule. Central sclerotized area short, wider than long, rounded at base ( Fig. 32E 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, short, not contrasting with setae of rest of tibiae; claws simple.

TERMINALIA. Body of penis elongate (W:L ratio: 0.28), slightly longer than apodemes; sides subparallel, in dorsal view, narrowing apicad in apical 1/6, apex truncate; in lateral view curvature moderate but stronger in basal ½ of length, width widening regularly from base to apical ⅓, then narrowing apicad, apex curved upward ( Fig. 32D View Fig ).

Sexual dimorphism

Females can be distinguished from males by the rostrum which is slightly longer and more downcurved in lateral view ( Fig. 32C View Fig ). The antennae are inserted at the apical 2/5 of the rostrum in lateral view (¼ in males). Males have costate 5 th elytral interstriae (all interstriae flat in females).

Life history

No information on host plants is available for this species, adults were collected in April ( Senegal) and October ( Nigeria).

Distribution

Gabon, Nigeria, Senegal. The reports from northern and southern Africa are doubtful, see Remarks section just below.

Remarks

In Schoenherr’s collection housed at NHRS, 2 male and 1 female specimens bearing a red type label and pinned in the box under the label “ ephippiger Gyll ” in the genus Derelomus were located. These specimens agree with the description given by Gyllenhal: “ Elytra (…) plaga lata, communi, brunnea, a basi paulo ultra medium extensa, ornata [elytra bearing a large brown band from base to beyond middle of length]”, and no other specimen can be related to this peculiar feature in the box. As a result, one of the males of this series is designated as the lectotype for the species name Derelomus ephippiger Gyllenhal, 1836 [here designated] and was relabelled accordingly. The other two specimens were labelled as paralectotypes. There has been a confusion on the type locality of the specimens used to describe this species: the original description states that the specimens are from the Cap . Bonae Spei. [ Cape of Good Hope, South Africa] and were provided by C. Quensel, but the labels under each specimen bear the locality “Barbaria? Quensel” an ancient term for the northern coast of Africa, extending from Morocco to Libya. Quensel never travelled to the Republic of South Africa and no specimens related to this species were ever collected in this country, suggesting that the type locality reported in the original description is erroneous. Moreover, this species appears absent from North Africa as well. The type locality for this species is thus left as uncertain. In our current knowledge, this species appears restricted to tropical Africa, from Senegal to Gabon. In the collection housed at MNHN, two female specimens labelled “ Gabon ” and corresponding in all aspect to the description of Hustache for Derelomus auberti were located. One of the specimens was designated as the lectotype for Derelomus auberti [here designated] and was labelled accordingly. The second specimen was labelled as a paralectotype. The rest of the series reported in the original description (ca 10 specimens) could not be located. The comparison between these lectotypes with the female lectotypes of D. ephippiger revealed no difference. As a result, the species name Derelomus auberti Hustache, 1932 is proposed as a junior synonym of Derelomus ephippiger Gyllenhal, 1836 [new synonymy].