Ochralea Clark, 1865

Hazmi, Izfa Riza & Wagner, Thomas, 2010, Revalidation and revision of Ochralea Clark, 1865 (Coleoptera: Chrysomelidae: Galerucinae) from the Oriental Region, Zootaxa 2530, pp. 47-59 : 49-52

Ochralea Clark, 1865

Type species: Ochralea nigricornis Clark, 1865 by monotypy.

Redescription. Total length: 7.75–14.40 mm

Head: Pale yellow or brownish, but black in about 20 % of material examined. Very finely punctate, with significant transverse impression between the posterior third of eyes, and a short median impression. Eyes large, strongly convex (fig. 1). Labial and maxillary palpi slender (fig. 2a), yellow or brown basally, occasionally darker towards apex. Labrum yellowish, brownish or blackish and occasionally much darker in the middle. Mandibles yellow or brown basally, and blackish towards the apex. Antennae entirely pale yellow in about 45 % of material examined; pale yellow with one to two apical antennomeres contrasting brown to black in all specimens with black head and prothorax (20 %); or only the basal three antennomeres pale to reddish-yellow and others dark brown to black (35 %). Antennae filiform, slender, extending to about the middle of the elytron (figs 1, 7, 12); first antennomere club shaped, second shortest, third antennomere about one third to slightly longer than second; length ratio of second to third antennomere 0.67–0.90 (mean: 0.83); fourth broader, about twice the length of the third, length ratio of third to fourth antennomere 0.37–0.50 (mean: 0.45; figs 8, 13).

Thorax: Pronotum transverse, narrowing slightly towards the anterior, broadest in the middle, protruding slightly at posterior angles (figs 7, 12). Shiny, smooth, and finely punctured without any transverse depression, but often with insignificant shallow longitudinal impression from the posterior angle in the basal third of pronotum. Pronotum usually yellow or yellowish-red, but black in about 20 % of material examined. Pronotal width 2.80–4.20 mm (mean: 3.76), length to width ratio 0.62–0.73 (mean: 0.66).

Scutellum large, triangular, impunctate, yellow, reddish-yellow or pale brown. Procoxal cavities partly open (fig. 2b). Mesothorax and metathorax yellow to brown. Mesosternum broad (fig. 2c). Elytra entirely pale yellow to yellow (in old specimens more brownish) in about 60 % of material; reddish-yellow throughout in 20 %; in specimens with black head and pronotum yellowish-red to reddish-brown with apical quarter dark brown to black.

Elytral punctation slightly coarser and denser than that of pronotum. Elytral length 6.00– 10.60 mm (mean: 9.14), maximal width of both elytra together 4.70–7.00 mm (mean: 6.16 mm), ratio of maximal width of both elytra together to length of elytra 0.62–0.80 (mean: 0.67). Alae fully developed (fig. 4). Legs long and slender, basal metatarsomere elongate (fig. 5). Pale yellow to reddish-yellow throughout in about half of material examined; others with coxa to femur yellow contrasting with the brown to black tibia and tarsus, all specimens with black head and pronotum of this coloration.

Abdomen: Pale yellow to brownish, but black in specimens with black head and pronotum. Last visible sternite in females rounded at apex, but with two deep parallel incisions, one on either side, in males (fig. 3).

Male genitalia: Outline of the median lobe and endophallic structures symmetrically arranged. Median lobe elongate, moderately curved ventrally, with basal half broad in dorsal view, tapering in the apical half, apex deeply incised. Endophallic sac clearly visible, endophallus with three pairs of spiculae in the middle. Tectum not incised apically, nearly reaching the apex of the median lobe (figs 9, 14).

Female genitalia: Spermatheca with a spherical nodulus, strongly sclerotized, with long and strongly curved cornu, terminating in a cap like structure or rounded (figs 10, 15). One or two pairs of bursal sclerites, with sclerotized spines (figs 11, 16).

Distribution: Recorded from most east Asian countries, including Malaysia, Indonesia, Philippines, Cambodia, Burma, Myanmar, Thailand, Brunei, Laos, Vietnam, Singapore, northwards to Southern China, westwards to Bangladesh and eastern India, eastwards to Sulawesi and and as far as the Wallace-line (fig. 6).

Diagnosis: Ochralea are relatively large galerucines (7.75–14.40 mm body length) with elongate basal metatarsomeres that distinguish them from most other galerucines of the same size. Other galerucine taxa with strongly elongate basal metatarsomeres, like Candezea Chapuis, 1879 (5.70–8.10 mm; Wagner & Kurtscheid, 2005) and Monolepta (3.00– 7.50 mm; Wagner 2007a) are considerably smaller. The dorsal coloration is either entirely yellow to yellowish- or brownish-red, but one distinct variation of O. nigripes has a black head, pronotum and apical quarter of the elytra. Such uniform coloration only occurs in a few species of Monolepta and Candezea , which usually have contrasting dorsal coloration, with transverse bands and spots.

The second and third antennomeres of Ochralea are short and almost the same size, as in Monolepta , which was the crucial character responsible for the synonymisation of these taxa by Weise (1924). The length ratio of the second to the third antennomere in Ochralea is 0.67–0.90, 0.82–1.10 in Monolepta , but differs in Candezea where it is 0.49–0.63. The pronotum of Ochralea is comparatively narrow, with a length to width ratio of 0.62–0.73, which is similar to the 0.52–0.65 of Monolepta , but significantly different from the species of Candezea , which have a much broader pronotum of 0.42–0.59. The procoxal cavities are partly open (fig. 2) as in most species of Monolepta and Candezea .

The median lobe of Ochralea is deeply incised apically, while it is not incised and usually rounded in Monolepta and carinated ventrally in Candezea . The tectum is not incised in Ochralea and Monolepta , but bears an incision in Candezea . The endophallic sac is clearly visible in Ochralea , with endophallic structures consisting of pairs of strong spiculae, similar to those in Candezea , but very different from the three distinct types of endophallic spiculae in Monolepta . The shape of the spermatheca of Ochralea resembles that of Monolepta ( Wagner, 2007a) with exception of the cap-like structure of the cornu, but is quite different from Candezea ( Wagner & Kurtscheid, 2005) .

Discussion: Besides the type species, nine other species of galerucines have been described in Ochralea . These are: O. ceylonica Harold, 1880 ; O. divisa Jacoby, 1889 ; O. fulva Baly, 1886 ; O. pallida Jacoby, 1892 ; O. pectoralis Harold, 1880 ; O. rufobasalis Jacoby, 1892 ; O. straminea Harold, 1880 ; O. imitans Jacoby, 1894 ; O. marginata Jacoby, 1884 . With an exception of the latter, which was transferred to Nadrana by Laboissiere (1936), all the other species were transferred to Monolepta by various authors ( Weise, 1924; Maulik, 1936). Next to the type species, we also checked type material of the other taxa listed above, and found out that O. pectoralis Harold, 1880 is a junior synonym to O. nigripes (Olivier, 1808) , and the others are not con-generic with Ochralea . Details on their morphology and transfer to other genera will be dealt with in subsequent publications.

On the other hand we checked some large species of Monolepta and Candezea and found that the recently described Monolepta wangkliana Mohammedsaid, 2005 needs to be transferred to Ochralea . Finally, this genus comprises only two valid species which are subsequently redescribed.