Brachelytrium

Key to the subgenera and species of Brachelytrium

1. Pronotal sculpture homogenous, consisting of regularly rounded or polygonal cells, each usually with well-developed central grains (Figs. 1–6); entire body black or dark bronze, matt, occasionally with coppery lustre or metallic; antennae serrate from third antennomere; elytra shortened, disc uneven; ventral surface very often with patches of white tomentum........................................................................................... subgenus Brachelytrium Obenberger... 2

- Pronotal sculpture finer, consisting of polygonal cells with indistinct central grains on disc and oblique, elongate cells or rugae laterally (Figs. 7, 8); body more lustrous, blue, bicolorous (pronotum and elytra of different colours) or bronze, cupreous or violet-bronze with pronotum red or purple laterally; antennae serrate from fourth antennomere; elytra less shortened in proportion, regularly convex; only metepimera with white tomentum................................................................................................................................................ subgenus Elytrobrachium Bílý & Bellamy... 21

2. Slender, relatively elongate species; length 4.4–5.7 mm; pronotum only 1.4 times as wide as long, elytra 1.6 times as long as wide; frontovertex in both sexes with two deep, vertical grooves for antennae in repose; anterior portion of frons between grooves with short, white pubescence; aedeagus as in Fig. 17; body length 4.4–5.7 mm; South Africa, Zimbabwe ......................................................................................................... B. (B.) fissifrons Bílý & Bellamy, 2000

- Shorter and more stout species; pronotum 1.5–1.8 times as wide as long, elytra 1.3–1.5 times as long as wide; head without grooves, frons with or without pubescence..................................................................................................... 3

3. Frons with distinct white, off-white or grey pubescence.............................................................................................. 4

- Frons completely glabrous.......................................................................................................................................... 12

4. Frontal pubescence white; setae two to three times longer than diameter of frontal punctures; frons flat without basal microsculpture; male unknown; body length 5.6 mm; South Africa ....... B. (B.) waterbergense Bílý & Bellamy, 2000

- Frontal pubescence off-white or grey; setae shorter, with length same as diameter of frontal punctures or shorter; frons flat or depressed with basal microsculpture......................................................................................................... 5

5. Smaller, slender species; elytra 1.6 times as long as wide; frons flat or with rather deep, rounded, medial depression; frontal cells always without central grains but with dense, basal microsculpture........................................................ 6

- Larger, more robust species; elytra 1.3–1.5 times as long as wide; frons flat or with wide, shallow, postclypeal depression; pronotal sculpture rugose, with sharp central grains; frontal cells with or without central grains........... 7

6. Smaller, more flattened species; frons with small but deep, rounded depression; pronotal sculpture finer with very small central grains; lateroposterior depressions well developed; frontal cells shallow but complete, rounded; male unknown; 4.0 mm; South Africa .................................................................... B. (B.) prolongum Bílý & Bellamy, 2000

- Larger, more convex species; frons flat; pronotal sculpture more rugose with sharp central grains; pronotum very convex without lateroposterior depressions; frontal cells very shallow, incomplete, nearly semicircular, open posteriorly; aedeagus as in Fig. 20; 4.7 mm; South Africa ........................................ B. (B.) globicolle Bílý & Bellamy, 2000

7. Frons anteriorly with wide, shallow depression; anterior margin of frontoclypeus widely, arcuately emarginate..... 8

- Frons flat; anterior margin of frontoclypeus straight; elytra 1.4 times as long as wide; more convex species............ 9

8. Elytra only 1.3 times as long as wide; frontal depression shallow; ventral surface with white, tomentose patches; aedeagus as in Fig. 15; body length 4.1–6.1 mm; South Africa ..................... B. (B.) straussae Bílý & Bellamy, 2000

- Elytra more parallel, 1.5 times as long as wide; frontal depression deep; ventral surface without tomentose patches; body length 5.2 mm; Kenya......................................................................................... B. (B.) purpureiventre sp. nov.

9. Pronotum as wide as elytra; abdomen shorter, elytra extending as far as opposite posterior angles of penultimate tergite (Fig. 4)............................................................................................................................................................. 10

- Pronotum distinctly wider than elytra; abdomen longer, elytra extending as far as opposite posterior angles of third visible tergite (Fig. 2).................................................................................................................................................. 11

10. More robust; anterior margin of frontoclypeus emarginate; frontal pubescence longer (setae longer than diameter of cells); aedeagus as in Fig. 13; body length 5.0– 5.3 mm; South Africa............ B. (B.) transvalense Obenberger, 1923

- Less robust; anterior margin of frontoclypeus straight; frontal pubescence very short (setae shorter than diameter of cells); aedeagus as in Fig. 12; body length 5.0– 5.3 mm; Namibia.................................................. B. niehusi sp. nov.

11. Large, more robust, matt; central grains on pronotum large, flat; elytral sculpture rough; aedeagus as in Fig. 19; body length 5.3–6.7 mm; Tanzania ....................................................................... B. (B.) tanzaniense Bílý & Bellamy, 2000

- Smaqller, slender, lustrous; central gains on pronotum small, sharp; elytral sculpture much finer.......................... 12

12. Frontal ocellation very fine and dense; pronotum 1.8 times as wide as long; pronotal ocellation wider, somewhat longitudinally prolonged along lateral margins; scutellum lustrous, as wide as long; tarsal claws slightly enlarged at base; male unknown; body length 4.3 mm; Mauritania .................................................. B. (B.) mauritanicum sp. nov.

- Frontal ocellation sparser, more rough; pronotum 1.5 times as wide as long; pronotal ocellation finer, homogenous; scutellum microsculptured, slightly longer than wide; tarsal claws not enlarged at base; aedeagus as in Fig. 11; body length 4.7–5.8 mm; Benin..................................................................................................... B. (B.) beninense sp. nov.

13. Frons deeply, widely excavated................................................................................................................................ 14

- Frons flat or slightly grooved or depressed medially............................................................................................... 16

14. More robust species; pronotal sculpture on disc finer, with flat central grains; elytra 1.5 times as long as wide..... 15

- Less robust species; pronotal sculpture on disc more rugose with small but sharp central grains; elytra 1.4 times as long as wide; frons of female bronze, male unknown; body length 4.8 mm; Namibia................................................. ................................................................................................................................... B. (B.) cavifrons Bílý & Bellamy

15. Entire body bronze; frons of male green with large, dark violet medial spot, those of female dark purple with narrow, golden green vitta along inner margins of eyes; antennae hardly reaching midlength of lateral pronotal margins; maximum pronotal width at midlength; meso- and metatibiae not enlarged posteriorly; aedeagus as in Fig. 14; body length 5.3–5.4 mm; Moçambique, South Africa................................................................ B. (B.) lesnei (Théry, 1934)

- Dorsal surface dark green, ventral surface blue-green; antennae slightly overlapping midlength of lateral pronotal margins; maximum pronotal width at anterior third; meso- and metatibiae slightly enlarged posteriorly; male unknown; body length 5.8 mm; South Africa ........................................................................... B. (B.) aeneum sp. nov.

16. Small, slender species; frons flat with small, deep, rounded, medial depression; entire body including frons black with slight coppery lustre; male unknown; body length 3.2 mm; Lesotho, South Africa, Zimbabwe...................................................................................................................................................... B. (B.) minusculum Obenberger, 1928

- Larger, more robust species; frons flat, or slightly grooved medially, very rarely with small, rounded depression; colouration of frons purple or golden-green............................................................................................................... 17

17. Short, robust species with nearly cordiform pronotum; elytra only 1.3 times as long as wide; pronotum with deep lateroposterior depressions; body dark bronze, frons and antennae dark purple, posterior pronotal angles and elytral base feebly reddish; male unknown; body length 4.2–4.4 mm; Botswana ... B. (B.) cordinotum Bílý & Bellamy, 2000

- Relatively slender species; elytra 1.4 times as long as wide; pronotum widely rounded laterally, widest just posteriad of mid-point but not cordiform; lateroposterior pronotal depressions small, shallow; body dark bronze or red-bronze, frons golden-green, purple or bronze with reddish tint.............................................................................................. 18

18. Frons slightly concave, bright purple in female, golden-green in male; body reddish bronze; pronotal sculpture with wide but flat central grains; aedeagus as in Fig. 18; body length 4.1–5.0 mm; Namibia.................................................................................................................................................................... B. (B.) namibiense Bílý & Bellamy, 2000

- Frons flat, bright purple or bronze with golden-green angles and clypeus in male, dark bronze with slight red tint in female; pronotal sculpture with small but sharp central grains.................................................................................. 19

19. Frontal sculpture consisting of large, rounded and very dense cells, each separated by very narrow interstitial carina.................................................................................................................................................................................... 20

- Frontal sculpture consisting of smaller, rounded cells, separating interstitial carina equal to half cell diameter; frons of male bronze with golden-green anterior angles and clypeus, of female bronze; ventral surface bronze in both sexes; aedeagus as in Fig. 16; body length 4.0– 6.1 mm; South Africa ................. B. (B.) holmi Bílý & Bellamy, 2000

20. Dorsal surface bronze; frons of male bright purple, that of female bronze; pronotal ocellation with well-developed central grains; scutellum as wide as long; aedeagus as in Fig. 10; body length 4.6–5.2 mm; South Africa................. .................................................................................................................................. B. (B.) africanum (Pochon, 1972)

- Entire body black; pronotal ocellation with indistinct central grains; scutellum1.2 times as long as wide; aedeagus as in Fig. 9; body length 5.6 mm; Kenya ....................................................................................... B. (B.) nigrum sp. nov.

21. Smaller (2.5–4.5 mm); pronotum without lateroposterior depressions; lateral portion of pronotum with oblique, elongate cells.............................................................................................................................................................. 22

- Larger (4.2–5.7 mm), more robust species; pronotum with well-developed lateroposterior depressions; lateral portion of pronotum with elongate, oblique rugae.......................................................................................................... 24

22. Entire body bronze; frons nearly flat; body length 2.5–3.5 mm; Yemen........................ B. (E.) yemeni Brechtel, 2000

- Blue to blue-violet or bicolorous species; frons widely, rather deeply impressed..................................................... 23

23. Distinctly bicolorous: elytra blue or blue-green, pronotum golden-orange or golden-red with large, subtriangular black spot reaching almost scutellum; frons golden green in male, dark blue in female; lateral portion of abdominal ventrites golden in male, purple in female; elytral sculpture very fine; anal ventrite shortly truncate; aedeagus as in Fig. 21; body length 3.1–4.5 mm; Namibia, South Africa, Zimbabwe........................ B. (E.) blairi Obenberger, 1931

- Elytra blue-violet; frons, pronotum and scutellum blue; ventral surface black with blue tinge; elytral sculpture more rough; anal ventrite widely rounded; body length 3.8 mm; Zambia ..................................... B. (E.) caeruleum sp. nov.

24. Dorsal surface dark bronze, anterior pronotal angles and lateral portions with reddish lustre (male) or dark purple (female); frons bright (male) or dark (female) purple; ventral surface black, lateral portions of ventrites bronze (male) or red (female); lateroposterior pronotal depressions shallow; pronotal ocellation with well-developed central grains; aedeagus as in Fig. 23; body length 4.2–5.7 mm; South Africa .................. B. (E) ventrale (Kerremans, 1911)

- Dorsal surface golden green (male) or blue (female), pronotal disc somewhat darkened; ventral surface golden green with blue tinge (male) or blue-green (female); lateroposterior pronotal depressions rather deep; pronotal ocellation with small, indistinct central grains; aedeagus as in Fig. 22; body length 4.2–5.3 mm; Kenya, Zimbabwe................. ............................................................................................................................................. B. (E.) metallicum sp. nov.