Bruchidius nataensis, Delobel, 2016

Delobel, Alex, 2016, Three newBruchidius species from Eastern and Southern Africa (Coleoptera: Chrysomelidae: Bruchinae), Acta Entomologica Musei Nationalis Pragae 56 (1), pp. 265-273 : 266-268

Bruchidius nataensis sp. nov.

( Figs 1–3 )

Type locality. Botswana, Central district, Nata.

Type material. HOLOTYPE: J (dissected [01914]), ‘ BOTSWANA sep., / Nata / 9-14.i.1997 / leg. M. Snizek // Holotype // Bruchidius / nataensis / A. Delobel des. 2015’ ( OLML) .

Description. Length: 2.8 mm; width: 1.7 mm.

Body moderately stout, pygidium slanted 5–10° from vertical. Integument reddish brown, elytra lighter, sternites testaceous to brown; basal segments of antenna testaceous, VIII–X dark brown to black, XI reddish; four anterior legs testaceous, darkened basally, posterior legs reddish brown; last visible tergite testaceous. Vestiture mixture of white, yellowish and brown setae; thin and light on head; on pronotum, sides white, disc with dense, yellowish scales and a longitudinal stripe of whitish setae; elytra mostly yellowish, with anterior half of interstriae 3 whitish, interrupted by small brown dot; brown dots also near middle of interstriae 7 and 9, and at apex of interstriae 8 and 9; last visible tergite uniformly yellowish, except for white small basal triangle.

Male. Head short, eyes strongly bulging, maximum head width about 1.5 times width behind eyes; eyes separated by 0.33 times head width including eyes; face wide, with distance between posterior rim of eyes and apex of clypeus / distance between eyes = 1.9; eye weakly cleft, width at bottom of sinus composed of eight ommatidia; frons with carina obsolete and large shining bulge posteriorly. Punctation of face small and dense, clypeus alutaceous, with rounded apex. Antenna ( Fig. 3 ) short, not reaching beyond posterior angle of pronotum; antennal segments I–IV submoniliform, V widened apically, longer than wide, apically about as wide as long, and following segments eccentric, transverse, XI apically rounded, 1.3 times longer than wide. Length of antennomeres: 1.3: 1.0: 0.9: 0.9: 1.1: 1.0: 1.1: 1.1: 1.0: 1.0: 1.6.

Pronotum trapezoidal, with sides straight, not expanded behind eyes, slightly wider at base than long (W/L = 1.12); oblique impression on sides of basal lobe very shallow; disc with deep ocellate, almost coalescent punctures. Elytra moderately elongated, 1.12 times longer than combined width, their sides convex, maximum width in basal third; disc convex, briefly flattened around scutellum; base of striae 3 and 4 with two comparatively large, obtuse teeth, closer to base of elytra than to each other. Striae on disc thin, diameter of punctures not larger than width of striae; interstriae with microsculpture and a few larger punctures. Hind femur moderately incrassate, 2.6 times wider than mid femur; mesoventral margin with small preapical denticle; hind tibiae apically moderately widened, with lateral, dorsomesal and ventral carinae complete; apex of tibia with mucro about half as long as width of tarsomere 1, lateral denticle about half mucro length, and dorsal denticles minute.

Abdomen with ventrite V emarginate, medially half as long as laterally; basal angle of ventrite I with depressed area bearing short, appressed setae. Last visible tergite shield-shaped, only slightly longer than wide (L/W = 1.05), moderately convex in apical half.

Genitalia. Median lobe ( Fig. 1 ) elongated (maximum width excluding basal strut / total length = 0.11), not widened apically; basal hood narrow, not notched posteriorly; ventral valve wide, its apex obtuse, with two groups of five setae; hinge sclerites absent; internal sac almost entirely smooth, with only short scattered trichoid sensilla along median lobe sides, and some minute spines near middle; distal bulb smooth. Basal strut narrow, without dorsal keel; lateral lobes cleft to about 45% their length; apex of parameres not widened, each one bearing about 15 setae of various lengths ( Fig. 2 ).

Female. Unknown.

Differential diagnosis. External morphology of the new species is similar to that of several Acacieae feeders, inside as well as outside the B. albosparsus species group (DELOBEL et al. 2015, DELOBEL & LE RU 2015). However, if we consider the peculiarities of aedeagus morphology (ventral valve shape in particular), B. nataensis seems related with two African species that do not belong to that group, and predate Dichrostachys cinerea (Wight & Arn.) seeds, namely B. mabwensis (Decelle, 1960) and B. securiger Delobel & Anton, 2003 ( DELOBEL & ANTON 2003, DELOBEL 2010); both species however show larger and much more serrate antennae, and their internal sac is lined with numerous sclerites. It may be assumed that the new species belongs to a large clade of Bruchinae comprising the B. albosparsus and B. ituriensis species groups, as well as B. securiger , B. mabwensis and B. meibomiaca (DELOBEL et al. 2015) . It is worth mentioning here that a similar ventral valve also exists in one Indian species with different external morphology, namely B. mendosus (Gyllenhal, 1839) .

Host plants. Unknown.

Etymology. The specific epithet (masculine adjective) refers to the type locality, Nata town in central Botswana.

Distribution. Botswana (Central District).

Figures

Figs 1–6. Genitalia and antenna of Bruchidius species:1–3 – B. nataensis sp. nov. (1 – median lobe; 2 – lateral lobes; 3 – male antenna). 4–6 – B. pluridentatus sp. nov. (4 – median lobe; 5 – lateral lobes; 6 – male antenna).