Bruchidius tumidulus, 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 : 270-271

Bruchidius tumidulus sp. nov.

( Figs 5 , 16–18 )

Type locality. Kenya, Nakuru Co., Kampi Ya Moto, 00°12.779′S, 36°00.143′E, 2035 m a.s.l.

Type material. HOLOTYPE: J (dissected [15102]), ‘ KENYA, Kampi Ya Moto / 2035 m, ex Acacia lahal pods / 00°12.779’S 36°00.143’E / septembre 2002, B. Le Ru coll. // Holotype Bruchidius tumidulus n. sp., Delobel & Le Ru des. 2015’ ( MNHN) . PARATYPES: 8 JJ 10 ♀♀, same data as holotype ; 2 JJ (dissected [02914, 14702]), 1 ♀, Makutano , ex Acacia nilotica subulata , 01°24.466’S 36°29.889’E, vi.2002, B. Le Ru coll. ; 2 JJ (1 J dissected [14602]), 1 ♀, Narok, ex Acacia lahal , 01°05.533’S 36°07.027’E, vi.2002, B. Le Ru coll. ; 2 JJ (dissected [02611], the other specimen used for DNA extraction), Machakos, ex Acacia seyal , 01°50.158’S 37°26.413’E, 23.i.2008, B. Le Ru coll, ( MNHN, CBGP) .

Description. Length: 1.7–2.2 mm; width: 1.0– 1.3 mm.

Body moderately stout, last visible tergite slanted 5 to 10° from vertical. Integument reddish brown to black, elytra black with anterior part of disc and sides brown; antennae and four anterior legs testaceous, posterior legs reddish brown, abdominal sternites black except upper part brown; last tarsomeres blackened; last visible tergite testaceous. Vestiture a mixture of thin whitish, yellowish and fulvous setae; on pronotum basal triangle, wide longitudinal line and two small dots white; elytra fulvous with lighter dots and stripes, posterior part of suture and apex forming wide dark triangle; epipleuron testaceous anteriorly; last visible tergite uniformly white in male, in female with pair of black longitudinal stripes.

Male. Head short, eyes strongly bulging, maximum head width about 1.5 times width behind eyes; eyes separated by 0.24 times head width including eyes; face narrow, with distance between posterior rim of eyes and apex of clypeus / distance between eyes = 3.0; eye moderately cleft, width at bottom of sinus composed of 5–6 ommatidia; frons with blunt carina and shiny bulge posteriorly. Punctation of face small and dense, clypeus visibly alutaceous. Antenna ( Fig. 16 ) moderately long, measuring 0.6 times body length; antennal segments 1–4 submoniliform, 5 widened apically, longer than wide, 6 apically as wide as long, and following segments moderately eccentric and transverse, 11 oblong, 1.6 times longer than wide. Lengths of antennomeres: 1.9: 1.0: 1.2: 1.6: 2.0: 1.9: 1.9: 1.8: 1.7: 1.5: 2.7.

Pronotum campaniform, at base wider than long (W/L = 1.4), its sides convex medially; oblique impression on sides of basal lobe wide and shallow; disc with strong and dense punctation. Elytra basally wider than pronotal base, maximum width beyond middle, longer than their combined width (L/W = 1.13), disc convex, dented elevation at base of striae 3 and 4, teeth as close to each other as 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 blunt preapical denticle; hind tibia moderately widened apically, with ventral, lateral and dorsomesal carinae complete; apex of tibia with mucro about half as long as tarsomere 1 width, lateral denticle almost as long as mucro, dorsal denticles very short.

Abdomen strongly telescoped, but ventrite 5 not clearly emarginated, its length medially as long as sternite 4; ventrite 1 without patch of dense setae in basal angle. Last visible tergite shield-shaped, only slightly longer than wide, moderately convex in apical half.

Genitalia. Median lobe ( Fig. 17 ) of moderate length (maximum width excluding basal hood / total length = 0.15), subcylindrical, strongly widened apically; basal hood oval, not notched apically; ventral valve large, subtriangular, with acute tip and two lateral groups of 4 setae; dorsal valve braced with sclerotized ring becoming very wide ventrally; no hinge sclerites; internal sac in basal half lined with hyaline tubercles, followed by strands of thin acute spines, hiding four medium-sized blunt sclerites in dorsal position; distally, two to five elongated teeth; apical bulb long, densely lined with very thin needles, gonopore not sclerotized. Basal strut ( Fig. 18 ) with large dorsal keel; lateral lobes cleft about 40 % of their length, apex of parameres with about 10 setae.

Female. Similar to male, but last visible tergite less convex, with median pair of black longitudinal stripes, ventrite 5 longer than ventrite 4, antennae slightly shorter.

Differential diagnosis. External morphology of this species is similar to Bruchidius albosparsus or B. tanaensis specimens with well contrasted colors, except for longer and entirely testaceous antennae, the elytra with black posterior triangle and testaceous epipleuron, the abdomen black with testaceous sides. However, the placement of the new species in the B. albosparsus species group remains doubtful, because male genital morphology is quite distinctive, without obvious relationship to other members of the group.

Host plants. Larvae develop in seeds of Vachellia lahal (Steud. & Hochst. ex. Benth.) Kyal. & Boatwr., V. nilotica subulata (Vatke) Kyal. & Boatwr. , and V. seyal (Del.) P.J.H. Hurter.

Etymology. The specific epithet (masculine) is the Latin word for ‘inflated’, which refers to the shape of the median lobe apex.

Distribution. Kenya (Kirinyaga, Machakos, Nakuru, and Narok Counties).

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).