Bonesioides Laboissière, 1925

Freund, W. & Wagner, TH., 2003, Revision of Bonesioides Laboissière, 1925 (Coleoptera; Chrysomelidae; Galerucinae) from continental Africa, Journal of Natural History 37 (16), pp. 1915-1976 : 1918-1924

Bonesioides Laboissière, 1925

Type species: Bonesioides coerulea (Allard, 1889) .

Ootheca coerulea Allard, 1889: 102 .

Redescription

Total length. 3.6–9.5 mm (adults); average total length for distinct species range between 3.9 and 9.1 mm. Generally, females are somewhat larger than males. Larvae and pupae unknown.

Head. Labrum, maxillary and labial palpus dark brown to black, rarely becoming paler apically; except in three species where labrum, maxillary and labial palpus is pale brown or reddish brown. Antenna dark brown to black, except of B. rubricollis which has entirely reddish brown antenna. Antenna usually extending towards end of metasternum. Basal antennal articles 1–4 rarely brownish red. Frons and vertex metallic blue, green or purple, except three species having reddish brown heads. Antennal article 2 always shorter than article 3, ratio of antennal article 2 to 3 (A2/A3): 0.51–0.83; article 4 nearly as long as articles 2 and 3 combined or longer, rarely shorter, ratio antennal article 3 to 4 (A3/A4): 0.50–0.81. Eye convex and ovate, sometimes very large, ratio width of eyes to eye distance (WE/DE): 0.47–0.99.

Thorax. Pronotum dark metallic green, blue or purple, exept for three above species, where pronotum is either reddish brown or black. Greatest width in the posterior third of pronotum, pronotum slightly trapezoidal. Prosternum very narrow and carinate between coxal cavities, prothoracic coxal cavities open behind (figure 2A). Pronotal length (PL; mean for distinct species): 0.62–1.62 mm, mean pronotal width (PW): 1.20–3.05 mm, mean ratio pronotal length to width (PL/PW): 0.49–0.58. Elytra dark metallic green, blue or purple, except pale brown in B. barombiensis or elytra brownish red at base and metallic black in the apical half in B. dimidiata . Mean elytral length (EL): 3.06–6.80 mm, mean elytral width of both elytra (EW): 1.68–4.07 mm, mean ratio elytral width to length (EW/EL): 0.55–0.65. Scutellum triangular, same coloration as elytra, except in Bonesioides barombiensis which has pale brown elytra, where scutellum black. Mesothorax and metathorax dark metallic green, blue or black, red to brownish red in the three species characterized by red head and pronotum. These species also with entirely red legs, or at least femur red, tibiae and tarsi black. Legs in species with metallic thorax black, rarely dark metallic green or blue (figure 5). Mean length of metatarsus to length of metatibia (TA/TI): 0.42–0.53. Alae fully developed (figure 4).

Abdomen. Five sternites (ventrites) visible, usually dark brown to black, rarely dark metallic green or blue, in B. dimidiata and B. rubricollis sp. nov. reddish brown (figure 3A, B).

Male genitalia. Median lobe symmetrical, short, parallel-sided at base and usually slightly conical apically (figure 10). Apically incised and dorso-ventrally slightly compressed. Tectum short, with narrow base, slightly expanded apically. Tegmum long, Y-shaped, attached in middle of median lobe. Parameres absent. Orifice wide, variable in shape, usually circular to rectangular. Endophallus with two asymmetrically arranged spiculae, either both right-curved, both left-curved or one spiculum left-curved, the other one right-curved. Endophallic spiculae varying in length, curvature and position. One species has three spiculae (figure 92). Endophallic brush usually covered by tectum, apical part of sclerotized ductus ejaculatorius protruding, only partly covered by tectum, sometimes very long, extending towards apical third of median lobe, where not covered by tectum.

Female genitalia. Spermatheca with slender or slightly expanded nodulus (figure 9). Middle part short and straight, rarely slightly curved. Cornu varying in length and curvature, from short, nearly right-angled to long, strongly curved. Bursa-sclerites very weakly sclerotized, hardly visible.

Distribution. Most species of Bonesioides are distributed in Central Africa, from Cameroon, through the Congo Basin to Kenya and Tanzania. A few species show a wider distribution, namely from Central to South Africa, while other species are restricted to West Africa, montane regions of the Albertine Rift (figure 6), Kenya and Ethiopia.

Diagnosis. Bonesioides are Afrotropical Galerucinae with elongated basimetatarsus (figure 5C), mean TA/TI: 0.42–0.53 (range of different species). Elytra are parallel-sided or slightly expanded apically. Coloration of the dorsum is homogeneously metallic green, blue or purple, except of B. purpureipennis , B. dimidiata and B. rubricollis sp. nov. where the head and pronotum are reddish brown, and B. barombiensis with a black pronotum and pale brown elytra. The underside is usually dark brown to black, rarely metallic green or blue, rarely entirely reddish brown, or at least thorax reddish brown. The legs are dark brown to black, rarely metallic blue or green, or not metallic reddish brown or very occasionally pale brown. The antennal articles are entirely dark brown to black, with articles 1–4 rarely paler, except one species which is entirely reddish brown antennae. Spots and bands on the elytra, which are typical characters for most Monolepta and Candezea species are absent. The body length in Bonesioides is highly variable and ranges from 3.9 to 9.1 mm. The third antennal article in Bonesioides is always longer than the second article (figure 8), A2/A3: 0.51–0.83. This is similar to Candezea , where the A2/A3 ranges from 0.62 to 0.85, but not in Monolepta which have the second and third antennal articles of approximately the same length (A2/A3: 0.85–1.10).

Previous authors classified the Galerucinae according to the condition of the prothoracic coxal cavities (Weise, 1923; Laboissière, 1925). Prothoracic coxal cavities in type-species of Bonesioides , Monolepta and Candezea are open, but other congeneric species and the only remaining species of Barombiella , which is closely related to Bonesioides , have completely closed prothoracic coxal cavities (cf. Wagner, 1999b). This character is obviously variable and not useful for generic delimitation. The pronotum is slightly trapezoidal in Bonesioides with is greatest width in the posterior third, but it is nearly rectangular in Monolepta and Candezea . The PW/PL in Bonesioides is 0.49–0.58, similar to Candezea (0.46–0.57), but narrower in Monolepta (0.52–0.65). Elytra in Bonesioides are slender, EW/EL range between 0.55 and 0.65, while the elytra are on average much broader in Candezea (0.62–0.70) and Monolepta (0.65–0.73). Furthermore, specimens of Candezea are dorso-ventrally strongly convexed, Monolepta is slightly to strongly convexed, while most Bonesioides are dorso-ventrally compressed or rarely convexed.

Size and endophallic structures of the median lobe in Bonesioides is very characteristic and show many peculiar differences compared to the median lobes of Monolepta and Candezea . In Bonesioides , it is comparatively short, apically deeply incised and usually conical towards the apex (figure 10). The tectum is very short, and the basal orifice is wide. The endophallic spiculae are asymmetrical, in contrast to the always symmetrical endophallic structures in Monolepta and Candezea . The apical parts of the endophallic structures are not, or only partly covered by the tectum. The gonoporus is usually visible on the protruding apical part of the ductus ejaculatorius in Bonesioides . The median lobe in Monolepta is elongated, not incised apically, the tectum is large and broad, and the basal orifice is small. The apical part of the endophallic structure, which bears distinct groups of spiculae, is completely covered by the tectum. In Candezea , the median lobe is elongated and narrow, not incised apically, the tectum is slightly incised apically and long, extending towards the apex of the median lobe, the basal orifice is very small. The apical part of the endophallic structure, which has three pairs of strong spiculae, is covered by the tectum. Spermathecae in Bonesioides are also very different compared to those of Monolepta and Candezea (figure 9, cf. Wagner, 1999b). The cornu is much shorter and broader than in Monolepta and Candezea . Bursa-sclerites are very weakly sclerotized in Bonesioides , in contrast to Monolepta and Candezea , which have strongly sclerotized, spiny bursa-sclerites. Barombiella violacea is closely related to Bonesioides . Besides several external characters such as metallic coloration, the shape of the median lobe is similar, but lacks endophallic spiculae and the broad endophallus has a wide distal opening which is not covered by the tectum (Wagner, 1999b).

In summary, Galerucinae from Continental Africa which have metallic-coloured head, pronotum or elytra, a slightly trapezoidal prothorax lacking a pronotal depression (figure 2A), moderately elongated basi-metatarsus (figure 5C), prothoracic coxal cavities open behind, and that peculiar type of median lobe with endophallic spiculae (figure 10) can be clearly assigned to Bonesioides .