Brachiacantha bahiensis Brèthes

Gordon, Robert D., Canepari, Claudio & Hanley, Guy A., 2014, South American Coccinellidae (Coleoptera), Part XVI: systematic revision of Brachiacantha Dejean (Coccinellinae: Hyperaspidini), Insecta Mundi 2014 (390), pp. 1-76 : 49-50

40. Brachiacantha bahiensis Brèthes

Brachyacantha bahiensis Brèthes, 1925a: 159 ; Korschefsky 1931: 103; Blackwelder 1945: 448.

Description. Male. Length 2.6 mm, width 2.0 mm; body oval, convex. Dorsal surface with head alutaceous, dull, pronotum weakly alutaceous, slightly shiny, elytron smooth, shiny. Color dark except head yellow, pronotum yellow with large, wide, black mediobasal macula extended 3/4 distance to anterior pronotal margin, macula not indented with yellow on apex, anterolateral angle widely emarginate with yellow; elytron dark brown with 5 small yellow spots, discal spot obliquely oval, mediolateral spot oval, projected inward, apical spot transversely oval with anterior border emarginate ( Fig. 230 ); ventral surface dark brown with antenna, mouthparts, legs yellow; abdomen dark brown with lateral 1/4 and ventrites 5–6 slightly paler brown. Head punctures small, separated by a diameter or less, each puncture about as large as an eye facet; pronotal punctures slightly larger than head punctures, separated by less than to slightly more than a diameter, elytral punctures slightly larger than on pronotum, separated by 1 to 2 times a diameter; metaventral punctures larger than on elytron, separated by a diameter or less medially, larger, separated by less than a diameter laterally. Clypeus emarginate apically, lateral angle rounded, surface with sparse, long pubescence. Eye canthus about 5 eye facets long, angled forward, apically rounded, yellow. Pronotum narrowed from base to apex, basal and anterior angles abrupt, lateral margin weakly rounded, basal margin without trace of bordering line medially. Epipleuron narrow, grooved, not descending externally, deeply emarginate for reception of femoral apices. Protibia narrowly flanged, flange less than width of remainder of protibia, outer margin straight, smooth, basal tooth small, length about 1/5 width of tibia at base, sponda not extended beyond protibial flange. Carinae on prosternal process widely separated at apex, slightly convergent toward base, joined at basal 1/3 of prosternum. Metaventrite without setal tuft. Basal abdominal ventrite without setal tuft. Abdomen with postcoxal line on basal abdominal ventrite flattened along posterior ventrite margin, extended forward apically, ventrite with sparse, long pubescence and small, dense punctures; ventrites 2–6 pubescent throughout, punctures fine, dense; ventrite 3 without cusp on each side of middle; 5th ventrite with apex broadly, weakly emarginate; 6th ventrite depressed medially, apex broadly emarginate. Apical tergite densely punctured, apex emarginate. Genitalia with basal lobe longer than paramere, wide, symmetrical, dorsal surface with large, arcuate, median keel, sides weakly arcuate in basal 5/6, apical 1/6 triangular, sides angled to acute apex, paramere short, weakly Psc, wide, slender, sinuate in dorsal view, apex rounded ( Fig. 231, 232 ); sipho robust, strongly curved in basal 2/3, with lateral alae just behind apex, basal capsule lightly sclerotized, inner arm short, triangular, apex rounded, outer arm wider and longer than inner arm, with small accessory piece, basal border feebly emarginate ( Fig. 233–235 ).

Female. Similar to male except head entirely black, pronotum with basomedian macula extended to anterior pronotal margin, anterolateral angle narrowly yellow. Genitalia with spermathecal capsule short, wide, widened from base to apex; bursal cap without sclerotized arms, apical strut short, base wide, apically slender ( Fig. 236 ).

Variation. Length 2.3 to 3.0 mm, width 2.4 mm. Elytron sometimes with black background, elytral spots variable in size, often larger or smaller than typical, female head may be entirely black or have a yellow spot at base of the frons.

Type locality. Bahia, Brazil.

Type depository. BMNH (lectotype here designated).

Geographical distribution. Brazil.

Specimens examined. 24. Brazil. Chapada; Mato Grosso; Santarem; Taquara. ( BMNH) ( CMNH).

Remarks. This species is another Brachiacantha with 5 yellow spots on a dark background. Most easily confused with B. groendali , males may usually be separated by the dark brown background and obliquely oval discal spot on each elytron, male pronotum usually without apical emargination of the basomedian macula, and male genitalia with a distinctive dorsal keel on the basal lobe. Females are more difficult to distinguish except by examination of genitalia, although even the genitalia are very similar in structure. Characters that distinguish this species and the bahiensis group are male genitalia with basal lobes having a sort of triangular apex and a large, arcuate dorsal keel.

The male lectotype in the BMNH is labeled. “Type(orange bordered disc)/ Type (handwritten)/ Bahia (handwritten)/58.60 (blue disc)/ Brachyacantha bahiensis Brethes

(handwritten).”

Figures

Figures 230–246. 230–236. Brachiacantha bahiensis. 230) Habitus. 231) Phallobase ventral. 232) Phallobase lateral. 233) Sipho. 234) Enlarged siphonal apex lateral. 235) Enlarged siphonal apex dorsal. 236) Female genitalia. 237–240. Brachiacantha pseudoarrowi. 237) Habitus. 238) Phallobase ventral. 239) Phallobase lateral. 240) Sipho. 241–246. Brachiacantha danielle. 241) Habitus. 242) Phallobase ventral. 243) Phallobase lateral. 244) Sipho. 245) Enlarged siphonal apex. 246) Female genitalia.