Ebenacobius rectirostris Haran, 2022

Haran, Julien, Benoit, Laure, Procheş, Şerban & Kergoat, Gael J., 2022, Ebenacobius Haran, a new southern African genus of flower weevils (Coleoptera: Curculioninae: Derelomini) associated with dicotyledonous plants, European Journal of Taxonomy 818 (1), pp. 1-54 : 16-18

Ebenacobius rectirostris Haran gen. et sp. nov.

urn:lsid:zoobank.org:act:960A68FE-5C99-4BBF-BFB2-3E4C4F72B87E

Figs 2B , 4C , 6B , 7A–C

Differential diagnosis

Ebenacobius rectirostris gen. et sp. nov. can be distinguished from other species of the genus by its short and straight rostrum in lateral view and its body integument glabrous, uniformly pale yellow or brownish at most with a transverse dark stripe at base and near middle of length between interstriae 5. Males lack a prosternal process. Ebenacobius rectirostris is morphologically closely related to Derelomus pallidus Fåhraeus, 1844 but in the latter species the interocular groove is lacking and the penis shows a distinct thickening near the base.

Etymology

This species is named in reference to its straight rostrum in lateral view, an apparently unique feature among species of Ebenacobius gen. nov.

Material examined

Holotype REPUBLIC OF SOUTH AFRICA • ♂; “Rep. of South Africa [REPUBLIC OF SOUTH AFRICA]; Limpopo Pr. Mulati; 10.vii.2018; J. Haran leg.” “-23.92 30.84; flowers Euclea natalensis ; JHAR01147_0101 ” “Holotype; Ebenacobius rectirostris ; Haran 2022”; SAMC .

Paratypes REPUBLIC OF SOUTH AFRICA – Limpopo Province • 1 ♂, 1 ♀; same collection data as for holotype; TMSA • 1 ♂, 1 ♀; same collection data as for holotype; SAMC • 1 ♂, 1 ♀; same collection data as for holotype; MNHN • 1 ♂, 1 ♀; same collection data as for holotype; SANC • 1 ♂, 1 ♀; same collection data as for holotype; NHMUK • 1 ♂, 1 ♀, 100 specs (preserved in ethanol); same collection data as for holotype; CBGP • 3 ♀♀; Lapalala Nature Reserve ; 23°30′36.0″ S, 28°10′12.0″ E; 21–22 Jan. 1987; R. Oberprieler leg.; SANC • 1 ♀; Mogol Nature Reserve , Ellisras District; 23°34′48.0″ S, 27°27′00.0″ E; 19–23 Nov. 1979; S.J. van Tonder and C. Kok leg.; light trap; SANC • 1 ♀; La Cotte, near Tzaneen; 9 Oct. 1979; Colin R. Owen leg.; USNM • 1 ♂; N Transvaal, Mmabolela estate; 22°40′ S, 28°15′ E; 8 Mar. 1973; Endrödy-Younga leg.; mercury vap. light; E-Y: 27; TMSA . – Free State Province • 1 ♀; Bloemfontein Naval Hill ; 29°06.296′ S, 26°13.581′ E; 27 Nov. 2017; R. Borovec leg.; FFWS • 1 ♀; 5 km west of Maseru; 22 Oct. 1988; W. Wittmer leg.; TMSA – Gauteng Province • 1 ♂; Kwalata; Jan. 2011; Ş. Procheş leg.; on flowers of Kiggelaria ; no. 2399 ; CBGP . – Mpumalanga Province • 2 ♂♂; Mbombela [formerly Nelspruit] ; 25°30′02.7″ S, 30°57′16.5″ E; 4 Apr. 2018; J. Haran leg.; on inflorescences of Cussonia spicata ; JHAR00843 ; CBGP • 2 ♀♀; Kruger National Park , Skukuza Research Camp ; 25°00′ S, 31°35′ E; 1–16 Dec. 2010; James Harrison leg.; UV light trap; TMSA • 1 ♀; Kruger National Park , Skukuza Research Camp ; 24°59′54.7″ S, 31°35′42.7″ E; 12–14 Dec. 1985; S. and J. Peck; thornscrub and riverine lightraps; CMN . – KwaZulu-Natal Province • 3 ♀♀; Qachas Neck; 30°09′36.0″ S, 28°40′48.0″ E; 30 Dec. 2018; J. Haran leg.; on inflorescences of Searsia sp. (Anacardiaceae) ; JHAR02070 ; CBGP . – Western Cape Province • 2 specs (preserved in ethanol); Stellenbosch Mountain ; 33°57′36.0″ S, 18°52′48.0″ E; 17 Aug. 2018; J. Haran leg.; on inflorescences of Searsia sp. (Anacardiaceae) ; JHAR01360 ; CBGP • 1 spec. (preserved in ethanol); Jonkershoek Nature Reserve ; 33°58′26.4″ S, 18°56′06.4″ E; 22 Jul. 2018; J. Haran leg.; beating fynbos; JHAR03295 ; CBGP • 1 ♂, 3 ♀♀; Gamka Nature Reserve ; 33°40.301′ S, 21°53.397′ E; 25 Oct. 2019; R. Borovec leg.; night beating and sweeping of fynbos; FFWS • 1 ♂; R62, 20 km of West Barrydale, Op de Tradowpas ; 33°55.265′ S, 20°30.805′ E; 15 Nov. 2016; R. Borovec leg.; sifting litter under Galenia africana L.; FFWS • 6 ♂♂, 4 ♀♀; North Uniondale, North Side Kammanasieberge ; 33°32.348′ S, 22°58.613′ E; 22 Oct. 2019; R. Borovec leg.; FFWS • 1 ♀; 10 km south of Elands Bay; 32°30′12.5″ S, 18°20′31.4″ E; 27 Jul. 2019; J. Haran leg.; beating flowering Lebeckia sericea (Fabaceae) ; JHAR02488 ; CBGP.

Description

Male

BODY LENGTH. 2.1–2.5 mm.

COLOUR. Body integument uniformly pale brown to brown (the dark triangle at base on elytra correspond to the dark sternites visible through the translucent integument of elytra), 5% of specimens with a dark dot on mid-length of interstriae 5, very few specimens with a dark transverse strip between interstriae 5 at base and near middle of length; dorsum with very short recumbent setae, glabrous and shiny in appearance.

HEAD. Rostrum as long as prothorax in lateral view, almost straight, regularly narrowing from base to apex; in dorsal view covered with recumbent non-contiguous setae; antennae inserted at apical 1/4 of length; head capsule glabrous and coarsely punctate in dorsal view; eyes convex, exceeding the lateral curve of head capsule in dorsal view; antennal funicle with segment 1 elongate, 1.5 × longer than wide, as long as 2–4, 4–7 wider than long.

PROTHORAX. Slightly wider than long (W:L ratio: 1.25), widest near middle of length, narrower there than elytra at humeral angles; sides subparallel in basal ⅔, narrowed in apical ⅓; apical constriction as long as width of apex of funicle; integument densely punctate, space between punctures micropunctate, narrower than diameter of larger punctures.

ELYTRA. Sides subparallel in basal half, widest near middle of length (W:L ratio: 0.70); humeri raised; apex jointly rounded; striae as wide or slightly narrower than interstriae, interstriae slightly convex, 9 forming a carina; scutellar shield rounded, glabrous.

ABDOMEN. Underside covered with minute whitish setae, glabrous in appearance.

LEGS. Profemora strongly thickened near middle of length; tibiae with external margin straight, armed with a small apical mucro; claws simple.

TERMINALIA. Body of penis elongate (W:L ratio: 0.30), as long as apodemes, widest at base, slightly narrowing from base to apical ⅓ of length, widening and then narrowing in apical ⅓, apex truncate; in lateral view curvature stronger in basal half, narrowing sharply near apex ( Fig. 6B ).

Sexual dimorphism

Females can be distinguished from males by their rostrum which is slightly narrower and longer than in ♂♂. Antennae inserted slightly closer to middle of length in ♀♀ than in ♂♂.

Remarks

Ebenacobius rectirostris gen. et sp. nov. is remarkably morphologically similar to Derelomus pallidus and was collected in sympatry with this species at several sites in the Western Cape Province (JHAR01360/2488/3295), though always in smaller numbers. Derelomus pallidus is associated with inflorescences of Euclea racemosa L. and seems restricted to the Western Cape Province (JH unpubl. obs.). Ebenacobius rectirostris by contrast is found abundantly in the North Eastern provinces of South Africa on inflorescences of Euclea natalensis . This peculiar case suggests that the genus Euclea was independently colonized by two derelomine genera and that these shifts resulted in strong morphological convergences. Ebenacobius rectirostris is a quite variable species, with some populations from the Western Cape Province exhibiting a slightly larger body size, longer rostrum and darker integuments. The sequencing of the COI barcode showed high intraspecific uncorrected p -distances ranging up to 2.74% between individuals from the Western Cape Province (JHAR01360) and the Mpumalanga (JHAR00843). This elevated level of intraspecific divergence suggests that several genetic lineages might exist in this species as currently considered. To date morphological examination of available specimens showed no morphological differences among specimens presenting a high level of genetic differentiation.

Life history

Ebenacobius rectirostris gen. et sp. nov. was collected in large numbers on flowers of Euclea natalensis in the Limpopo Province. The records in the Western Cape Province suggest that this species may use other species of Euclea as host plants. The few isolated records on inflorescences of Anacardiaceae , Araliaceae and Fabaceae likely correspond to host plants only used as shelter or refuge by adults. Adults are attracted by UV lights and have been collected by sifting leaf litter, suggesting that this species may be active at night and hide during the day at the base of plants. This species was recorded in sympatry with E. atratus gen. et comb. nov. Adults were collected almost all year round.

Distribution

This species is widely distributed in the Republic of South Africa, in the Gauteng, Kwazulu-Natal, Limpopo, Mpumalanga and Western Cape Provinces.

Figures

Fig. 2. A–I. Habitus of males of Ebenacobius Haran gen. nov. in dorsal view (part 1). A. E. curvisetis Haran gen. et sp. nov. B. E. rectirostris Haran gen. et sp. nov. C. E. duplicatus Haran gen. et sp. nov. D. E. grobbelaarae Haran gen. et sp. nov. E. E. costalis (Fåhraeus, 1844) gen. et comb. nov. F. E. thoracicus Haran gen. et sp. nov. G. E. xhosa Haran gen. et sp. nov. H. E. san Haran gen. et sp. nov. I. E. kuscheli Haran gen. et sp. nov. Scale bars = 1 mm.

Fig. 4. A–J. Habitus of males of Ebenacobius Haran gen. nov. in lateral view (part 1). A. E. curvisetis Haran gen. et sp. nov. B. E. thoracicus Haran gen. et sp. nov. C. E. rectirostris Haran gen. et sp. nov. D. E. xhosa Haran gen. et sp. nov. E. E. duplicatus Haran gen. et sp. nov. F. E. san Haran gen. et sp. nov. G. E. grobbelaarae Haran gen. et sp. nov. H. E. kuscheli Haran gen. et sp. nov. I. E. costalis (Fåhraeus, 1844) gen. et comb. nov. J. E. mulanjensis Haran gen. et sp. nov. A–J = not to scale.

Fig. 6 (part 1). A–I. Male genitalia of Ebenacobius Haran gen. nov., penis in dorsal (left) and lateral (right) view.A. E. curvisetis Haran gen. et sp. nov.B. E. rectirostrisHaran gen. et sp. nov.C. E. duplicatus Haran gen. et sp. nov. D. E. grobbelaarae Haran gen. et sp. nov. E. E. costalis (Fåhraeus, 1844) gen. et comb. nov. F. E. thoracicus Haran gen. et sp. nov. G. E. xhosa Haran gen. et sp. nov. H. E. san Haran gen. et sp. nov. I. E. kuscheli Haran gen. et sp. nov. A–I = not to scale.