Bruchidius quadrispinosus, 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 : 265-268

Bruchidius quadrispinosus sp. nov.

( Figs 2–3 , 10–12 )

Type locality. Kenya, Nairobi Co., Nairobi, icipe research complex, Kasarani Constituency-International Centre of Insect Physiology and Ecology ( ICIPE), 01°13.230′S, 36°53.636′E.

Type material. HOLOTYPE: J (dissected [11108]), ‘ KENYA, Nairobi , ICIPE / ex Acacia xanthophloea pods / 01°13.230’S 36°53,636’E / 11.i.2008, B. Le Ru coll. // Holotype // Bruchidius quadrispinosus n. sp., Delobel & Le Ru des. 2015’ ( MNHN) . PARATYPES: 1 ♀, same data as holotype ( MNHN) ; 1 J, Kenya-S, Kibwezi, Hunters’ Lodge, 2.xii.1997, M. Snizek, dissected ( OÖLM) .

Description. Length: 2.9 mm; width: 1.6 mm.

Body moderately stout, last visible tergite slanted about 20° from vertical. Integument testaceous to dark reddish brown, with elytral suture and sides blackened; antennae and four anterior legs testaceous, posterior legs reddish brown, abdominal sternites testaceous, with central part darkened or not; last tarsomeres and antennomeres (8)9–10(11) blackened; last visible tergite testaceous in male, largely black in female. Vestiture made of scaly, whitish, fulvous and blackish setae, with white markings: on pronotum, a wide basal triangle and longitudinal line becoming thinner anteriorly and two small dots; elytra fulvous with lighter dots, more strikingly at basal third of intervals 3, 5, 7, 9, apex dark; last visible tergite almost uniformly white in male, in female narrowly greyish anteriorly and laterally with basal white triangle, rest of tergite black.

Male. Head short, eyes strongly bulging, maximum head width about 1.5 times width behind eyes; eyes separated by 0.3 times head width including eyes; face wide, with distance between posterior rim of eyes and apex of clypeus / distance between eyes = 2.4; eye moderately cleft, width at bottom of sinus composed of 7–8 ommatidia; frons with blunt carina and strong and shiny bulge posteriorly. Punctation of face small and dense, clypeus visibly alutaceous. Antenna ( Fig. 10 ) moderately long, measuring 0.38 times body length; antennal segments 1–4 submoniliform, 5 slightly widened apically, as wide as long, and following segments strongly eccentric, transverse, 11 apically rounded, 1.5 times longer than wide. Lengths of antennomeres: 1.6: 1.0: 1.2: 1.2: 1.2: 1.2: 1.2: 1.2: 1.3: 1.3: 2.2.

Pronotum sub-trapezoidal, transverse, at base much wider than long (W/L = 1.7), its sides slightly convex medially; oblique impression on sides of basal lobe strong; disc with strong and dense punctation. Elytra basally wider than pronotal base, slightly longer (L/W = 1.08) than their combined width, disc flattened; dented elevation at base of striae 3 and 4, teeth closer to each other than to elytron base; striae narrow, with small punctures, interstriae wide and flat, strongly alutaceous. Hind femur moderately incrassated, twice wider than median femur; mesoventral margin with small acute preapical denticle; hind tibia short, strongly widened towards apex, with ventral, lateral and dorsomesal carinae complete; apex of tibia with mucro shorter than tarsomere 1 width, lateral denticle about half mucro length. First tarsomere ventrally with small acute denticle.

Abdomen with ventrite 5 strongly emarginated, its length medially about half as long as sternite 4, about one third its lateral length; ventrite 1 with patch of dense setae at basal angle well developed. Last visible tergite shield-shaped, only slightly longer than wide, strongly convex in apical half, its apex strongly turned under.

Genitalia. Median lobe ( Fig. 11 ) of moderate length (maximum width excluding basal hood / total length = 0.20), subcylindrical, moderately widened apically; basal hood narrow, not notched apically; ventral valve subtriangular, with sinuated sides, tip acute and bearing numerous sensilla, with two lateral groups of 5–6 setae; dorsal valve braced with sclerotized ring; pair of hinge sclerites; internal sac elongated, lined in basal third with hyaline ctenoid scales and small needles; four large thorns in central third, followed by smooth zone, devoid of needles or setae; apical bulb large, densely lined with very thin needles, gonopore large, circular. Basal strut ( Fig. 12 ) with obsolete dorsal keel; lateral lobes slender, cleft 70 % of their length, pubescent; apex of parameres with about 6 long and 10–12 shorter setae.

Female. Similar to male, but last visible tergite less convex, ventrite 5 about as long as ventrite 4. Darker than male: integument almost entirely black, except antennae and legs, only slightly darker than male; elytral disc brown, rest of elytra black, its vestiture checked black, brown and yellowish, with large black sutural marking in middle of intervals 1–3.

Differential diagnosis. The external morphology of B. quadrispinosus sp. nov. is very similar to that of the Bruchidius albosparsus species group as a whole. General body shape and color, and more particularly the presence of a black marking in the middle of elytral suture (striking in female specimen) are typical for members of the group. The large thorn-like spines in central part of the internal sac are of a type never found in the B. albosparsus group, but thorn-like sclerites do exist, even though in a smaller size and in a different arrangement, in at least two other members of the group, namely B. uberatus (Fåhraeus, 1895) and in another, yet undescribed species. Also, the pair of anterior sclerites usually named ‘hinge sclerites’ is quite similar to those found in B. albosparsus itself.

Host plant. Larvae develop in seeds of Vachellia xanthophloea (L.) Willd.

Etymology. Specific epithet (masculine adjective) meaning ‘with four spines’, a reference to the ornamentation of internal sac.

Distribution. Kenya (Makueni and Nairobi County).

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 6–12. Genitalia and antenna of Bruchidius species. 6–9 – B. horridus sp. nov. (6 – male antenna; 7 – median lobe; 8 – lateral lobes; 9 – spermatheca). 10–12 – B. quadrispinosus sp. nov. (10 – male antenna; 11 – median lobe; 12 – lateral lobes).