Elaeidobius plagiatus ( Fåhraeus, 1844 ) Haran & Beaudoin-Ollivier & Benoit & Kuschel, 2020

Haran, Julien M., Beaudoin-Ollivier, Laurence, Benoit, Laure & Kuschel, Guillermo, 2020, Revision of the palm-pollinating weevil genus Elaeidobius Kuschel, 1952 (Curculionidae, Curculioninae, Derelomini) with descriptions of two new species, European Journal of Taxonomy 684, pp. 1-32 : 20-21

Elaeidobius plagiatus ( Fåhraeus, 1844) comb. nov.

Figs 1G , 3C , 4G , 5 C–L, 7

Derelomus plagiatus Fåhraeus, 1844: 94 .

Derelomus ciliatus Hustache, 1924: 74 [syn. by Marshall 1930: 575].

Material examined

Lectotype

BETWEEN GHANA AND CONGO RIVER • ♀; “Guinea. Westermann” “♀” “Typus” “ Derelomus plagiatus (Fahr. 1844) Kuschel 2007 ” “ Holotype ♀ Derelomus plagiatus Fahraeus 1844 Kuschel 2007 ” “ NHRS-JLKB000065509 ” “Lectotype ♀ Derelomus plagiatus Fahraeus 1844 Haran 2020 ”; NHRS.

Other material

ANGOLA • 3 ♂♂, 1 ♀; CE Salazar ; 9.16º S, 14.55º E; 14 May 1973; Carvalho leg.; oil palm inflorescence; TMP .

DEMOCRATIC REPUBLIC OF CONGO • 1 ♂, lectotype of Derelomus ciliatus Hustache, 1924 [here designated], labelled as “ Elaeidobius plagiatus ( Fåhraeus 1844) Kuschel 2009 ”; Haut-Uelé, Moto ; 1922; L. Burgeon leg. MRAC • 1 ♂, paralectotype of Derelomus ciliatus Hustache, 1924 [labelled as] “ Elaeidobius plagiatus ( Fåhraeus 1844) Kuschel 2009 ”; same collection data as for preceding; MRAC • 1 ♂, paralectotype of Derelomus ciliatus Hustache, 1924 , [labelled as] “ Elaeidobius plagiatus ( Fåhraeus 1844) Kuschel 2009 ”; Kindu; Nov. 1913; L. Burgeon leg.; MRAC.

GHANA • 3 ♀♀; Western region , Pretsea; 4.55º N, 1.52º W; 30 m a.s.l.; 26 Aug. 1967; Endrödy-Younga leg.; beating oil palms; TMP • 2 ♂♂; Godbe ; 2015; on inflorescences of E. guineensis ; JHAR00283_0102/0103 ; CBGP.

NIGERIA • 1 ♂; Obaretin ; 2006; JHAR00272_0103 ; CBGP.

CAMEROON • 1 ♂; Edu Ngat ; 2008; JHAR00291_0101 ; CBGP • 1 ♂; Kienké; 2009; JHAR00293_0101 ; CBGP.

Diagnosis (♂ ♀)

BODY LENGTH. 2.1–3.4 mm.

COLOUR. Yellowish or pale reddish brown; reddish or dark brown on head, rostrum, underside, a large trapezoidal central area on pronotum, a stripe on interstria 6 in basal half and an oblique band between interstriae 3 or 4 to 8 before declivity; male with long erect setae on elytral margins and erect setae on suture and swelling at the base of interstria 4.

HEAD. Forehead in male sharply carinate on sides near eyes, flat or impressed, in female not or obsoletely carinate on sides, not impressed; rostrum in male as long as prothorax, or a fraction longer, robust, moderately downcurved, without erect hairs or tubercle on underside, in female 1.5 × as long as prothorax.

PROTHORAX. Trapezoidal, with nearly straight sides; disc nearly flat in lateral view, medially with two shallow impressions and two vague impressions between middle and apex; median impressions with small fovea on either side of middle; marginal carina in male obsolescent at least on basal half, carinate at apex near collar, distinctly projecting forward.

ELYTRA. In both sexes shiny, with slightly rounded sides, widest near middle, in male tectiform, distinctly sloping to the sides; striae gradually fading towards apex; base of interstria 4 in male not or slightly tumescent, with erect setae on the swelling similar to those on suture; interstria 9 in male swollen and bearing long erect setae throughout, in female costate on basal half, here rendering stria 8.

ABDOMEN. Tergites well-pigmented, entire; tergite 7 advancing strongly forward, with 9–11 plectral granules.

GENITALIA. Penis nearly as long as combined length of last 3 ventrites, Body symmetrical, 3.3 × as long as apodemes, about 3 × as long as than wide (ratio w/l: 0.32), with rather large frena ( Fig. 4G ).

Life history

In inflorescences of the oil palm, Elaeis guineensis (Arecaceae) ( Mariau & Genty 1988).

Distribution

Benin (Cotonou, Lobé); Cameroon (Bota, Kienke, Mbalmayo, Moliwe, Tiko); Democratic Republic of Congo (Beni: Ituri Forest, Haut-Lopori, Haut-Uelé: Moto, Kindu, Yambula); Ghana (Aburi, Accra, Kumasi); Nigeria (Ibadan, Ife); Togo (Kolo)

Remarks

Elaeidobius plagiatus is distinguished in the male by long erect setae on margin of elytra, on suture and at base of interstria 4, in female by a large dark trapezoidal central area on the pronotum and a rather wide apical half of the foretibiae. The usually long marginal erect setae of males can be very short as well, as is the case with the paralectotype of D. ciliatus from Kindu ( Congo) that Hustache took to be a female. Such males are also observed in low proportions in Angola.

Elaeidobius plagiatus was described by Fåhraeus as Derelomus plagiatus from “ Guinea ”, an area that comprised the current zone between Ghana and the Congo River. In the collection of Fåhraeus housed at NHRS, a female specimen with the locality “ Guinea Westermann” and bearing a red “Typus” label was located. As no particular holotype specimen was designated in the original description, this specimen was designated as the lectotype for Derelomus plagiatus Fåhraeus, 1844 and labelled accordingly. Derelomus ciliatus Hustache, 1924 was described based on a series of individuals from two localities in the Democratic Republic of Congo (Haut-Uelé, Moto, 1922 and Kindu, 1913). This species was later put in synonymy with D. plagiatus Fåhraeus (= Elaeidobius plagiatus Fåhraeus ) by Marshall (1930) but no particular specimen from these series was designated as holotype. In the collections of the MRAC, three male specimens from these localities and bearing the red labels “ Holotypus ” and “ Paratypus ” were located. The specimen from Haut-Uelé and bearing the label “ Holotypus ” is here designated as the lectotype for D. ciliatus Hustache. The second specimen from Haut-Uelé and the one from Kindu, both bearing the label “ Paratypus ” are labelled as paralectotypes for this species.

Figures

Fig. 1. Habitus of males and females of species of Elaeidobius Kuschel, 1952. A. E. bilineatus (Hustache, 1924) comb. nov., Dakar, Senegal. B. E. spatulifer (Marshall, 1950) comb. nov., holotype, Thysville, Democratic Republic of Congo (MRAC). C. E. subvittatus (Faust, 1898), Dakar, Senegal. D. E. kamerunicus (Faust, 1898) comb. nov. (JHAR00209). E. E. pilimargo Haran & Kuschel sp. nov. (JHAR00409). F. E. piliventris Haran & Kuschel sp. nov. (JHAR02182). G. E. plagiatus (Fåhraeus, 1844) comb. nov. (JHAR00272). H. E. singularis (Faust, 1898) comb. nov. (JHAR00283). Scale bars = 1 mm.

Fig. 3. Head and prothorax in lateral view of species of Elaeidobius Kuschel, 1952 (Part 2). A. E. pilimargo Haran & Kuschel sp. nov. (JHAR00409). B. E. piliventris Haran & Kuschel sp. nov. (JHAR02182). C. E. plagiatus (Fåhraeus, 1844) comb. nov. (JHAR00272). D. E. singularis (Faust, 1898) comb. nov. (JHAR00283). Not to scale.

Fig. 4. Penis of males of species of the genus Elaeidobius Kuschel, 1952 in dorsal (left) and lateral (right) view. A. E. bilineatus (Hustache, 1924) comb. nov., Dakar, Senegal. B. E. spatulifer (Marshall, 1950) comb. nov., holotype, Thysville, Democratic Republic of Congo (MRAC). C. E. subvittatus (Faust, 1898), Dakar, Senegal. D. E. kamerunicus (Faust, 1898) comb. nov. (JHAR00209). E. E. pilimargo Haran & Kuschel sp. nov. (JHAR00409). F. E. piliventris Haran & Kuschel sp. nov. (JHAR02182). G. E. plagiatus (Fåhraeus, 1844) comb. nov. (JHAR00272). H. E. singularis (Faust, 1898) comb. nov. (JHAR00283). Scale bars = 100 µm.

Fig. 5. Details of morphology of Elaeidobius spp. A. Pronotum of E. subvittatus (Faust, 1898) in dorsal view showing the flat pronotum and the lateral cuticular expansion near head. B. Pronotum of E. subvittatus (Faust, 1898) in ventral view, showing the trilobate cuticular expansion between the coxae. C. Pronotum of E. plagiatus (Fåhraeus, 1844) comb. nov. in dorsal view showing the fovea on either side of midline. D. Apex of rostrum of E. bilineatus (Hustache, 1924) comb. nov. in lateral view. E. Apex of rostrum of E. subvittatus (Faust, 1898) in lateral view showing the protruding tubercle on underside. F. Elytra of E. bilineatus (Hustache, 1924) comb. nov. in dorsal view. G. Elytra of E. subvittatus (Faust, 1898) in dorsal view. H. Elytra of E. singularis (Faust, 1898) comb. nov. in lateral view. I. Elytra of E. kamerunicus (Faust, 1898) comb. nov. in lateral view. J–K. Abdominal sternites of male of E. piliventris Haran & Kuschel sp. nov. showing the median impression of the first two segments, flanked by a fringe of semi-erect hairs. L. Scutellum of E. plagiatus (Fåhraeus, 1844) comb. nov. in lateral view showing erect setae on tumescent base of interstria 4. M. Pronotum of dark specimens of E. subvittatus (Faust, 1898) in dorsal view. Not to scale.