Bruchidius spathiger, Delobel & Ru, 2015

Delobel, Alex & Ru, Bruno Le, 2015, New Bruchidius species reared from Vachellia (Fabaceae: Mimosoideae: Acacieae) seeds from Eastern and Southern Africa (Coleoptera: Chrysomelidae: Bruchinae), Acta Entomologica Musei Nationalis Pragae 55 (1), pp. 261-272 : 268-270

Bruchidius spathiger sp. nov.

( Figs 4 , 13–15 )

Type locality. Kenya, Kajiado Co., Olepolos, 01°26.064′S, 36°41.002′E, 1862 m a.s.l.

Type material. HOLOTYPE: J, ‘ KENYA, Olepolos, 1862 m / ex Acacia etbaica pods / 01°26,064’S 36°41,002’E / 19.i.2013, B. Le Ru coll.// Holotype // Bruchidius spathiger n. sp. / Delobel & Le Ru des. 2015’ ( MNHN). Paratypes: 3 JJ 6 ♀♀ (2 JJ, 2 ♀♀ dissected), same data as holotype ( MNHN, CBGP); 2 JJ 2 ♀♀ (1 J dissected), ‘ ZIM- BABWE / Umguza, 19.26S / 27.52E 28.v.1977 / F.R. Monyoro // ex seeds of / Acacia karroo // National Coll. / of Insects, S. Afr. / AcPL 1848 // Bruchidius / senegalensis (Pic) det. / S.J. van Tonder / 1980 // Bruchidius spathiger n. sp. / Delobel & Le Ru des. 2015’ ( NCIP); 1 J (dissected), ‘ SOUTH AFRICA, Tvl / Codrington, 25.03S / 28.18E, v.1977 / S.J. van Tonder // ex seeds of / Acacia tenuispina // National Coll. / of Insects, S.Afr./ AH 509 // Bruchidius / senegalensis (Pic) det. / S.J. van Tonder / 1980 // Bruchidius spathiger n. sp. / Delobel & Le Ru des. 2015’ ( NCIP).

Description. Length: 2.4–2.6 mm; width: 1.4–1.5 mm.

Body short, stocky, last visible tergite slanted about 5° from vertical in male. Integument of lighter coloured specimens yellowish red with brownish markings; darker specimens mostly black, with lighter markings; extreme apex of elytra light brown. Four basal segments of antenna testaceous, rest of antenna variously darkened, but last segment always lighter; fore and middle legs, including coxae, yellowish red; hind legs reddish brown. Ventral side (including centre of abdominal sternites) black, sides reddish brown. Base of elytra darkened, especially humeral area, disc with common black spot beyond mid-length, not reaching apex. Vestiture constituted of whitish, yellowish and black setae in various proportions, dense, covering integument, recumbent. Areas of denser white hair: on pronotum two small spots and area in front of scutellum; scutellum; on elytra scutellar area, one elongated stripe just before mid-length on interval 5 and scattered spots; irregular transverse stripes of dark (brownish to blackish) setae on elytra: just behind base on interstriae 3, 5, 7, 9 and before middle on interstriae 5, 7, 8 and 9; often sutural area black near middle, usually fused with dark coloration of apex. Last visible tergite with more or less homogeneous whitish vestiture, usually with basal white triangle and incomplete longitudinal stripe.

Male. Head short, strongly constricted behind eyes; eyes large, bulging, maximum head width 1.8 times width behind eyes; ocular sinus comparatively shallow; eyes separated by only 0.18 times head width including eyes; face narrow, distance between posterior rim of eyes and apex of clypeus / maximum head width = 0.67; post-ocular lobes hardly visible; carina on frons distinct but shallow, micro-punctured; inter-ocular tubercle distinct, also not shiny. Antenna ( Fig. 13 ) reaching pronotal base; antennal segments 1-3 subcylindrical, segment 4 slightly widened at apex, segment 5 and following serrate, 11 oval (L/W = 1.9); lengths of antennomeres: 1.7: 1.0: 0.9: 1.4: 1.5: 1.4: 1.5: 1.5: 1.6: 1.7: 3.0.

Pronotum transverse (at base 1.4 times wider than long), campaniform, with slightly bi-sinuated sides, not laterally expanded behind eyes. Elytra short, 1.1 times as long as their combined width. Sides almost parallel; disc convex. At base of stria 2 very small tooth, at base of striae 3 and 4 two small teeth on moderate protuberance, teeth about twice closer to each other than to elytral base. Striae on disc punctured; punctures strong, wider than striae, distance between punctures 2 to 3 times their diameter; interstriae flat, with strong micro-punctation. Hind femora moderately incrassated, at their widest 2.5 times wider than mid femora; mesoventral margin with small preapical denticle; hind tibiae simple with ventral carina complete, dorsomesal carina incomplete, lateral reaching base; apex of tibia with mucro about 3 times longer than lateral denticle, dorsal denticles about as long as lateral ones.

Abdomen simple; basal angle of sternite 1 with small area of denser setae; sternite 5 strongly emarginated; last visible tergite slightly longer than wide, convex in basal half, convexity steadily increasing towards apex.

Genitalia. Median lobe ( Fig. 14 ) slender (maximum width excluding basal hood / total length = 0.14); ventral valve widened towards apex, with tip in-turned, bearing numerous sensillae and on each side row of 3–5 setae in basal half; dorsal valve wide and strongly sclerotized; median part of internal sac with large central sclerite made up of several small fused units, then three pairs of large hook-like sclerites; first pair the largest, often bearing one or two additional hooks; distal bulb lined with minute tubercles and spines, gonopore D-shaped, hardly sclerotized; basal strut comparatively small, without apical emargination. Parameres long and thin, separated in about 75% of their length; tegminal strut with strong longitudinal dorsal keel ( Fig. 15 ).

Female. Similar to male, but antennal segments 1–5 submoniliform, 6–10 serrate, but less markedly than in male; segments 1–5 (6) and 11 testaceous, rest testaceous to dark brown; vestiture of last visible tergite whitish and black, or entirely black, with white longitudinal stripe briefly interrupted beyond middle. Ovipositor moderately elongated, vagina membranous, without dentate sclerite, but in some specimens with brown markings, spermathecal body smooth, small and spherical, apical diverticulum moderately long and slim, strongly curved. Differential diagnosis. The new species was erroneously identified as B. senegalensis (Pic, 1912) (= B. aurivillii Blanc, 1889 ) by VAN TONDER (1985), which is understandable in view of its similarity to various members of the B. albosparsus species group. However, the very peculiar shape of the ventral valve differentiates the new species from all other members of the group. Such type of ventral valve is quite unusual among Bruchidius species : in addition to B. spathiger sp. nov., it may be found only in B. mussooriensis Arora, 1980 from South- East Asia and B. lichenicola (Wollaston, 1854) from Madeira and the Canary Islands. The larval diet of the new species is however quite distinct from that of the latter. Bruchidius mussooriensis larvae feed in seeds of Alysicarpus vaginalis (L.) DC. ( Fabaceae : Desmodieae ) ( DELOBEL 2010), B. lichenicola larvae in those of various Loteae : Lotus campylocladus Webb & Berthel. , L. glaucus Sol. (Delobel, unpublished data), and L. hillebrandii H. Christ. ( YUS RAMOS 2008). This would indicate that wide lamella-shaped ventral valves evolved independently in different parts of the world, in species with different diets.

Host plants. Reared from seeds of Vachellia karroo Hayne , V. etbaica Schweinf. , and V. tenuispina Verdoorn. The same sample of V. etbaica pods collected in Olepolos yielded two other seed beetles, namely Bruchidius quadrisignatus (Fåhraeus, 1871) and Tuberculobruchus longipennis (Pic, 1902) . Bruchidius spathiger sp. nov. adults were the last to emerge from the pods, what indicates either a slower preimaginal development, or oviposition occurring posteriorly on the pods.

Etymology. Forged Latin adjective (masculine), from spatha, lamella and gere, to carry.

Distribution. Kenya (Kajiado County), Republic of South Africa (Transvaal), Zimbabwe (Matabeleland North Province).

Figures

Figs 1–5. Habitus of Bruchidius species. 1 – B. horridus sp. nov., J paratype. 2 – B. quadrispinosus sp. nov., J holotype. 3 – B. quadrispinosus sp. nov.,♀ paratype. 4 – B. spathiger sp. nov.,J paratype (Kenya). 5 – B. tumidulus sp. nov., J paratype (Kenya, Kampi Ya Moto).

Figs 13–18. Genitalia and antenna ofBruchidius species.13–15 – B.spathiger sp.nov.(13 – male antenna; 14 – median lobe; 15 – lateral lobes). 16–18 – B. tumidulus sp. nov. (16 – male antenna; 17 – median lobe; 18 – lateral lobes).